Optimizing Obsessive-Compulsive Symptom Measurement with the Yale-Brown Obsessive Compulsive Scales, Second Edition (2025)

Abstract

The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) is a widely used measure for assessing the presence and severity of obsessive-compulsive disorder (OCD) symptoms. The Y-BOCS Second Edition (Y-BOCS-II) was developed, in part, to more comprehensively evaluate symptom severity, especially in extremely ill patients, and improve consistency in detecting and incorporating avoidance behaviors. We present 3 case studies that demonstrate the enhanced ability of the Y-BOCS-II to 1) detect fluctuations in symptom severity among extremely ill patients, 2) systematically incorporate avoidance variables for more accurate ratings, and 3) maintain strong convergence with the Y-BOCS in assessing patients presenting with mild to moderate symptoms. In addition, we outline how to obtain both Y-BOCS and Y-BOCS-II scores within 1 administration by adding Y-BOCS item 4 to the Y-BOCS-II assessment, then “back-coding” the Y-BOCS-II ratings to Y-BOCS ratings and using Y-BOCS item 4 in place of Y-BOCS-II item 2. The use of this method allows for more robust data collection while providing comparability across the literature.

Keywords: obsessive-compulsive disorder, Yale-Brown Obsessive Compulsive Scale, symptom severity, avoidance, treatment, assessment, reliability, validity

The Yale-Brown Obsessive Compulsive Scale (Y-BOCS)¹ has been widely utilized for assessing the presence and severity of obsessive-compulsive disorder (OCD) symptoms since the 1980s. The Y-BOCS is a clinician-rated semi-structured interview, which consists of a symptom checklist (67 items) and a 10-item severity scale with subscales that separately assess the severity of obsessions and compulsions (5 items each). Each item is rated from 0 (no symptoms) to 4 (extreme symptoms), covering domains of time spent on symptoms, distress and interference from symptoms, and resistance and control over symptoms. Additional items assess severity in the domains of insight, avoidance, indecisiveness, overvalued sense of responsibility, pervasive slowness, and pathological doubting. However, these additional items are deemed “investigational items” for the purpose of providing additional information in assessing the severity of obsessions and compulsions, but they are not included in the final score. This design provides a systematic measure of OCD symptom severity that is not influenced by the type or number of obsessions or compulsions that a patient experiences. The Y-BOCS has been consistently used across intervention and phenotyping studies, which is somewhat unique from the situation for classes of disorders for which there are often several commonly used outcome measures. The psychometric properties of the Y-BOCS, including generally good reliability and validity ^2–5 and sensitivity to change,^6,7 have been supported. Although over time there has been some debate about the factor structure of the Y-BOCS,^8–10 analyses broadly support the theorized 2-factor structure of obsession severity and compulsion severity.^11–13

Despite the strengths and widespread use of the Y-BOCS, there are also some disadvantages. These include: a) limited severity range, b) limited guidance about capturing avoidance, and c) poor psychometric properties of the resistance against obsessions item. These weaknesses have important implications. For example, the maximum symptom duration threshold set in the Y-BOCS (> 8 hours) limits its ability to detect symptom improvements in very severe cases (eg, an improvement from 16 hours of daily symptoms to 11 hours could not be captured by the Y-BOCS item scoring). This potential ceiling effect is of particular importance for outcome trials of interventions; especially those focusing on patients with severe illness such as studies involving neurosurgical interventions.^14,15 In addition, various forms of avoidance behaviors can often mask the full impact of symptoms on a patient’s life, leading to imprecise ratings if not adequately factored into symptom assessment (eg, ratings of time, distress, and interference).¹⁶ To address these issues, the Y-BOCS-II was developed in an effort to improve the sensitivity of this scale, especially for those with more severe symptoms, and to further incorporate the impact of active avoidance behaviors into patient scores.¹⁷ The range of severity ratings was expanded and specific language was included in the prompts and rating anchors of the Y-BOCS-II to ensure a more consistent assessment of severity and avoidance.

OBJECTIVE

Since its introduction, the Y-BOCS-II has been employed in a fairly limited manner in OCD research, with preference shown toward use of the original Y-BOCS. While there are advantages to this approach (eg, comparability across studies, ease of interpretation, not having to learn a new scale), utilization of the Y-BOCS-II may advance the field by having a more sensitive, psychometrically sound scale. Given this background, the purpose of this article is to illustrate scenarios in which the Y-BOCS-II measures subtle, yet relevant, clinical changes beyond the Y-BOCS that are important for consideration by clinicians and researchers, while also demonstrating its strong coherence with the original measure. These case examples were developed by the authors, based on clinical experiences with individuals presenting with severe OCD symptoms. The primary differences between both versions of the scale are detailed below, along with a methodology for obtaining scores for both measures within a single administration. Then, 3 case studies are presented in which the Y-BOCS-II detected fluctuations within the extreme severity range, systematically incorporated avoidance variables, and/or maintained consistency with the Y-BOCS in measuring a patient with moderate symptom severity.

DIFFERENCES BETWEEN THE Y-BOCS AND Y-BOCS-II

The Y-BOCS-II was revised from its predecessor in several ways, with the goal of incorporating advances in the understanding of OCD phenomenology by increasing sensitivity to changes in symptom severity, systematically integrating avoidance variables in ratings, and improving the psychometric properties of the scale, while maintaining consistency with the Y-BOCS where possible. Indeed, investigations into the psychometrics of the Y-BOCS-II have demonstrated strong internal consistency, sensitivity, reliability, and validity, and a more stable factor structure.^10,18–23 Primary updates in the Y-BOCS-II are highlighted below to demonstrate the significant role they play in assessing scenarios such as those presented in this article.

Increased Range of Scores for Each Item and for the Total Score

One of the most significant changes in the Y-BOCS-II was expanding the scoring criteria for each item from a 5-point scale (0–4) to a 6-point scale (0–5), allowing for increased sensitivity to change at the upper (more severe) end of the scale. This change was made to address limitations of the Y-BOCS in capturing improvements or symptom variance in extremely ill patients. To accomplish this while still preserving psychometric cohesion between the scales, the most severe anchors for each item (eg, value of 4) in the Y-BOCS were expanded into 2 options, while the lower anchors remained generally the same. The only exceptions to this expansion of the upper end of the scale are the 2 degree of control items (for obsessions and compulsions) and the resistance against compulsions item, where the middle anchor was expanded to capture more variability and change within the moderate range of these metrics.

Overall, these changes resulted in an increase in the upper limit of the total score of the scale from 40 to 50. As we demonstrate below, this additional 10-point range at the top of the scale is particularly helpful in capturing “missing variance” in very severe patients, while the majority of patients will still receive scores under 40 as they would have on the original scale. For example, the Y-BOCS-II can ascertain within this upper 10-point range when a patient who was previously housebound and required assistance with most activities of daily living is now able to get dressed, go to the bathroom, and go out to the grocery store on his or her own. In addition, it can detect change in a patient who previously experienced near constant intrusion of obsessions for 14 to 16 hours a day who now has some small breaks between intrusive thoughts, with total time spent on obsessions down to 10 to 12 hours a day. While these 2 patients may still be severely impaired, both have experienced clinically meaningful improvements that can be reflected in their Y-BOCS-II scores.

Y-BOCS Resistance Against Obsessions Item Replaced by Obsession-Free Interval Item

In the Y-BOCS, item 4 assesses the amount of effort a patient exerts to resist obsessive thoughts when they occur. While effort to resist can be a useful measure of illness severity for compulsive behavior, this construct becomes more ambiguous to assess in the context of obsessions, in part due to the spontaneous and uncontrollable nature of intrusive thoughts. Patients may misinterpret “resistance” as the ability to avoid or prevent onset of obsessions altogether, which will often be endorsed as difficult to impossible, inadvertently skewing their score on this item. Additional confusion is encountered when this item is applied to patients undergoing exposure and response prevention (ERP) therapy. ERP, the gold standard psychotherapy for OCD, trains patients not to resist obsessions, but rather let them come without thought suppression and even attempt to trigger disturbing thoughts during exposure tasks.²⁴ Therefore, scores on this item can become artificially inflated in patients that may actually be less severely affected due to successful application of this therapeutic technique. The ambiguity of the resistance against obsessions item has also been implicated as problematic to confirmatory analyses of psychometric properties of the Y-BOCS, while the “obsession-free interval” (item 2) has been shown to provide useful, nonredundant information.⁹ Inclusion of the obsession-free interval incorporates additional information about the time burden patients experience from their obsessions. This information is particularly useful for assessing change in severity at the high end, where the most severely ill patients may experience constant or near constant intrusion of obsessive thoughts. These patients may experience an improvement in their obsession-free interval before they see a significant reduction in their overall time occupied by obsessive thoughts (item 1). Conversely, this item can also capture variance in patients who experience frequent intrusions (high score on item 2), but are able to dismiss thoughts very promptly, resulting in less time overall occupied by obsessions (low score on item 1).

Systematic Integration of Active Avoidance

Incorporating a comprehensive understanding of avoidance behaviors is also a key part of assessing a patient’s clinical profile. Since the development of the original Y-BOCS, the understanding of avoidance behaviors and their disruptive role in OCD symptomatology has evolved, although approaches for classifying and integrating these behaviors for diagnostic and assessment purposes have not been standardized. While avoidance behaviors may be especially prominent in extreme cases, the influence of avoidance can span the whole spectrum of OCD severity.^16,25–27. If not properly considered, a patient’s symptoms can be underestimated when avoidance is being practiced in addition to, or in place of, overt compulsions.

While given consideration in the Y-BOCS (ie, item 12 of “investigational items” assessing overall avoidance with regard to compulsions), avoidance is not systematically included in calculations of total symptom severity, whereas the Y-BOCS-II includes specific prompts to direct attention toward avoidance variables on certain items, as well as eliciting information concerning the presence of ritualized avoidance.¹⁶ At this extreme end, patients may engage in “active” avoidance measures, which take time, effort, and concentration, such as donning and doffing personal protective equipment for outings or planning specific routes when driving to avoid highways. Discrete behaviors like these serve the purpose of reducing anxiety and can become ritualized, just like compulsions. In instances where ritualized avoidance can be identified and takes up a measurable amount of time or frequency throughout the day, these behaviors should be factored into the “time spent performing compulsive behaviors” item on the Y-BOCS-II. Distress associated with these active avoidance behaviors should also be considered when evaluating Y-BOCS-II item 9 (distress if compulsive behavior [or avoidance] prevented).

On the other end of the avoidance spectrum, passive avoidance is less effortful and occurs when patients are broadly avoidant to reduce exposure to anxiogenic triggers; for example, remaining at home to avoid people or keeping the TV off to avoid hearing upsetting news content. However, when someone stops doing laundry, taking showers, or going outside to prevent contact with the triggers to their compulsions, they engage in more pronounced passive avoidance that is still disruptive to their lives. In these instances, a patient may report less distress, interference, and time occupied by compulsions, which must be carefully evaluated to determine if the improvement is true or artificial. The impact of passive avoidance on functioning is evaluated in the Y-BOCS-II items assessing distress if compulsive behavior (or avoidance) is prevented (item 9) and interference due to compulsions (item 10). Care must also be taken by the clinician or evaluator not to include generalized patterns of avoidance in these ratings, which are more indicative of a person’s lifestyle or personality.

Obtaining Scores for Both the Y-BOCS-II and the Y-BOCS in a Single Assessment

For the purposes of comparing patient outcomes on the Y-BOCS-II and Y-BOCS, it is easily possible to obtain scores for both editions of the Y-BOCS in a single assessment. This is done simply by administering all of the items on the Y-BOCS-II (using the 6-point scale) with the addition of item 4 (resistance against obsessions) from the Y-BOCS (using the 5-point scale). The Y-BOCS-II items are then “back-coded” to a 5-point scale by changing all scores of 5 to scores of 4 and transferring all other scores (1 to 4) “as is” to their counterpart items in the Y-BOCS. The item scores must be transferred exactly by the number rated, not by the rating description, with the exception of ratings of 5. Therefore, a score of 2 on Y-BOCS-II is a score of 2 on Y-BOCS, a score of 4 on Y-BOCS-II is transferred as a score of 4 on Y-BOCS, and a score of 5 on Y-BOC-II is converted to a score of 4 on Y-BOCS. It is also important to note that Y-BOCS-II item 2 (obsession-free interval) is not added to the final score of the Y-BOCS, and that Y-BOCS-II item 4 (resistance against obsessions) must be included in its place. When translating back-coded Y-BOCS scores, it is important to consider that certain items (namely items 7 and 8) may have slightly higher ratings in patients with extensive avoidance behaviors, due to the additional emphasis in the Y-BOCS-II on assessing these domains. On balance, the authors’ clinical experience suggested that clinicians were attempting to capture avoidance when rating the Y-BOCS, but the lack of guidance contributed to potential inconsistency. Regardless, this “back-coding” method helps ensure cohesion between the 2 measures, allows for more robust data collection, and facilitates comparison of clinical outcomes broadly across the literature.

CASE A: SEVERE CASE WHOSE TREATMENT PROGRESS DIFFERED AS A FUNCTION OF USING THE Y-BOCS-II OR THE Y-BOCS

Background

Patient A, a single 30-year-old white male who had onset of OCD symptoms at approximately 15 years of age, was referred to a neurosurgery clinic by his long-term cognitive behavioral therapist for a higher level of care. His previous treatments included multiple trials of selective serontonin reuptake inhibitors (SSRIs), clomipramine, antipsychotic augmentation, over 2 years of weekly ERP, and 12 weeks in a partial hospitalization program, all of which were unsuccessful in alleviating his symptoms. Secondary diagnoses included major depressive disorder and generalized anxiety disorder.

The patient’s most prominent obsessions centered around magical ideation and fears of something terrible happening to his loved ones if his compulsions were not performed until they felt just right. Other common obsessions included fear of thinking or saying certain words, phrases, or numbers that might somehow cause harm to himself and others. The patient reported these intrusive thoughts occurred almost continually throughout the day, with only 15 to 30 seconds between intrusions. His compulsions included counting words in a sentence before speaking to avoid the number 6, repeated crossing of boundaries (eg, walking back and forth through a door frame) until it felt “just right,” and going over previous conversations in his mind to neutralize negative thoughts he believed might cause harm to others. Patient A’s symptoms were so severe that he was housebound and dependent on family members for activities of daily living, such as going to the bathroom, getting dressed, and preparing meals. Due to the superstitious nature of his obsessions and poor insight, it had been especially difficult for him to benefit from ERP. For example, he was very resistant to considering his compulsions as illogical or accepting that no actual harm would occur if they were not performed adequately. Unrelated coincidences were often cited as supportive evidence for this faulty thinking.

Treatment

Table 1 shows the item scores on the Y-BOCS and Y-BOCS-II for Patient A . Figure 1 illustrates Patient A’s total Y-BOCS and Y-BOCS-II scores over time. Prior to neurosurgical intervention, the patient’s treatment team administered the Y-BOCS-II with the addition of item 4 from the Y-BOCS, using the back-coding method to obtain scores for both the Y-BOCS-II and Y-BOCS. This assessment method was used throughout the patient’s course of treatment to obtain outcome scores that could be compared to other cases. At baseline, Patient A scored a 4 on degree of control over obsessive thoughts (Y-BOCS-II item 3) and resistance against compulsive behavior (Y-BOCS-II item 8), and a 3 on resistance against obsessions (Y-BOCS item 4). He received a score of 5 on all of the other items, resulting in a total score of 48 on the Y-BOCS-II. With the back-coding conversion, the patient received a score of 4 on all Y-BOCS items, with the exception of the score of 3 on Y-BOCS item 4, resulting in a total score of 39 on the Y-BOCS. Table 2 presents a detailed illustration of how the patient’s baselines scores were converted from Y-BOCS-II scores to Y-BOCS scores.

Table 1.

Item scores on the Y-BOCS and Y-BOCS-II for Patient A


Time of asessment	BL	1 mo	2 mo	3 mo	4 mo	5 mo	6 mo		BL	1 mo	2 mo	3 mo	4 mo	5 mo	6 mo
Y-BOCS								Y-BOCS-II
1. Obsession-Time Spent	4	4	4	4	4	4	4	1. Obsession-Time Spent	5	5	5	4	4	4	4
2. Obsession-Interference	4	4	4	4	4	3	3	2. Obsession-Free Interval	5	4	5	4	4	4	3
3. Obsession-Distress	4	4	4	4	4	4	4	3. Obsession-Control	4	4	5	4	4	4	3
4. Obsession-Resistance	3	3	4	3	3	2	2	4. Obsession-Distress	5	5	5	5	4	4	4
5. Obsession-Control	4	4	4	4	4	4	3	5. Obsession-Interference	5	4	4	4	4	3	3
Obsession Sub Scale Total	19	19	20	19	19	17	16	Obsession Sub Scale Total	24	22	24	21	20	19	17
6. Compulsion-Time Spent	4	4	4	4	4	4	3	6. Compulsion-Time Spent	5	5	5	4	4	4	3
7. Compulsion-Interference	4	4	4	4	4	3	3	7. Compulsion-Resistance	4	4	4	4	4	3	2
8. Compulsion-Distress	4	4	4	4	4	4	3	8. Compulsion-Control	5	4	4	4	4	3	3
9. Compulsion-Resistance	4	4	4	4	4	3	2	9. Compulsion-Distress	5	5	5	5	4	4	3
10. Compulsion-Control	4	4	4	4	4	3	3	10. Compulsion-Interference	5	4	4	4	4	3	3
Compulsion Sub Score Total	20	20	20	20	20	17	14	Compulsion Sub Scale Total	24	22	22	21	20	17	14
Y-BOCS Total Score	39	39	40	39	39	34	30	Y-BOCS-II Total Score	48	44	46	42	40	36	31

Open in a new tab

Figure 1. Y-BOCS and Y-BOCS-II Scores Over Time for Patient A.

Open in a new tab

Table 2:

Back-Coding Y-BOCS-II scores to the Y-BOCS using Patient A’s Baseline Scores

Optimizing Obsessive-Compulsive Symptom Measurement with the Yale-Brown Obsessive Compulsive Scales, Second Edition (2)

Open in a new tab

Patient A was then implanted with a deep brain stimulation device (DBS), bilaterally targeting the nucleus accumbens/ventral striatum. During the initial programming session of the patient’s DBS device, he experienced acute improvement in mood and reduction in anxiety, along with a boost in energy levels.

The patient was reassessed 1 month later and, while his scores for the Y-BOCS showed no changes, noticeable improvements were captured on the Y-BOCS-II, where he scored a total of 44. During this initial month of stimulation, continued improvements in mood and energy allowed Patient A to engage with more ease in activities of daily living with less supervision. No longer housebound due to his symptoms, he went out for daily walks around the neighborhood, dined at a restaurant with family members on a few occasions, and got a haircut at a local salon. Other improvements included a slight increase in his ability to control or delay compulsions (with difficulty) when outside the house, and the ability to go up to 20 minutes free of obsessive thoughts when visiting with family members. However, the time occupied by his obsessions and compulsions remained near constant throughout the day and caused overwhelming and disabling distress a majority of the time. These modest improvements during this first month were reflected in the Y-BOCS-II through decreases in scores from 5 to 4 on relevant items (Table 1).

During the second month of treatment, the effects of stimulation had begun to fade and he experienced a slight increase in the frequency and intensity of his obsessive thoughts, returning to an extremely short obsession-free interval of less than 1 minute. He completely and willingly yielded to all obsessions without attempting to control them, resulting in no control over the intrusive thoughts. Symptom fluctuation during this month was recorded as increases in scores (from 4 to 5) on Y-BOCS-II items 2 and 3, as well as an increase (from 3 to 4) on Y-BOCS item 4, resulting in a score of 40 on the Y-BOCS and a 46 on the Y-BOCS-II. DBS stimulation amplitudes were increased bilaterally in an effort to compensate for the habituation effects the patient had experienced.

Although the patient’s OCD remained severe and difficult to control, he noticed subtle and steady improvements in his overall symptomatology over months 3 and 4 of treatment. He continued to go out for walks near his home, but he was still unable to socialize with other people outside his family. However, he was able to experience very short obsession-free intervals of about 45 minutes, allowing him time to engage in other recreational activities that had previously been nearly impossible, such as reading and writing. The time spent on obsessions and compulsions decreased from 12 or more hours a day, to approximately 9 hours a day, and he felt more capable of independently completing routine activities, including bathing, eating, and dressing himself. In addition, the distress caused by the obsessions and compulsions transformed from being extreme and overwhelming (reported consistently up until this point) to very severe/highly disturbing and difficult to manage. By month 4, his overall Y-BOCS-II score dropped to 40, while his overall Y-BOCS score stayed at 39, showing no change from baseline. Up to this point, the patient’s improvements were recognized primarily through decreases in scores from 5 to 4 on most Y-BOCS-II items.

Patient A experienced additional, substantial improvements at month 5, especially with regard to his compulsive symptoms, which he was trying harder to resist. Sustained decreases in distress from obsessions and compulsions helped him feel motivated to join a local book club, where he began socializing with people he willingly chose to meet. While he was still experiencing intrusive thoughts for about 8.5. hours a day with very short symptom-free intervals, he was able to expend more effort at resisting obsessions and controlling compulsions (score of 2 on Y-BOCS item 4, and 3 on Y-BOCS-II items 7 and 8), especially when socializing. By month 6, the patient’s scores had dropped significantly to 30 on the Y-BOCS (a 23% decrease from baseline) and 31 on the Y-BOCS-II (a 35% decrease from baseline). He remained engaged in his local book club, would cook easy meals, completed household chores independently, and reported feeling more energetic and happier throughout the day with more time to plan personal activities. He made stronger efforts to resist both obsessions and compulsions (now a score of 2 on both resistance items), resulting in more success at dismissing intrusive thoughts, decreased overall time spent performing compulsions, and decreased distress related to compulsions (scores of 3 on related items). Although Patient A was still not working or attending school as he desired, he was successfully participating in activities inside and outside his home, and his social functioning was no longer impaired.

CASE B: PATIENT PRESENTING WITH PRIMARY AVOIDANCE BEHAVIORS, WITH THE Y-BOCS-II MORE CLEARLY CAPTURING SEVERITY ASSOCIATED WITH AVOIDANCE BEHAVIORS

Background

Patient B was a married 48-year-old Asian female with a 24-year history of OCD. At baseline, she was taking 20 mg escitalopram daily with modest benefit and met with her psychiatrist regularly for medication management. She was also taking part in an observational research study investigating the prospective course of OCD. She was seen by both her psychiatrist and the research team on a monthly basis, and her symptoms were assessed separately by each group. Her psychiatrist preferred to use the original Y-BOCS to track her progress, while the research group employed the Y-BOCS-II. For this scenario, we compared scores from the 2 versions of the Y-BOCS coded separately by different raters, and not derived from the back-coding method.

The themes of the patient’s obsessions involved contamination concerns related to germs, specifically with bodily waste and fluids such as blood and urine. Her primary concern was that she would cause others to become ill if she was not careful or clean enough, especially after using the bathroom. This resulted in a fear of shared items and public spaces. Primary compulsions included cleaning/sanitizing items she touched, excessive bathing, and repeated handwashing, especially in public places. Although her compulsions were burdensome, requiring additional time to complete routine activities throughout the day, she was still able to maintain a job and socialize with others outside of her home. However, when the COVID-19 pandemic began to spread throughout the United States, she experienced a sharp increase in obsessional distress. This resulted in an increase in avoidance behaviors in efforts to limit contact with germs and contaminants that would trigger distressing and time-consuming cleaning rituals. By employing proper screening and protective measures, both her psychiatrist and the research team were able to safely assess her in person during this timeframe.

Treatment

Table 3 shows the item scores on the Y-BOCS and Y-BOCS-II at each visit for Patient B. Figure 2 illustrates Patient B’s total Y-BOCS and Y-BOCS-II scores over time. When the patient was initially assessed in March 2020, she reported an obsession-free interval of approximately 2.5 consecutive hours a day (score of 3 on Y-BOCS-II item 2) and that she had some control over the obsessions, sometimes being able to stop or ignore them. This endorsement of control translated into a score of 2 on Y-BOCS item 5 from her psychiatrist, and a score of 3 on the corresponding Y-BOCS-II item 3 from the research group. For the compulsion subscales, the patient reported not engaging in many compulsions while out in public, and making a moderate amount of effort to resist them overall (score of 2 on the resistance against compulsions items on both Y-BOCS scales). She was spending approximately 2 hours a day performing compulsions (score of 2 on the corresponding items on both scales), and had a moderate degree of control over the behaviors (score of 2 on corresponding items on both scales), which in turn only caused moderate levels of distress that remained manageable (score of 2 on corresponding items on both scales). These compulsions interfered moderately with the patient’s social and occupational performance, but all aspects of her life remained manageable (score of 2 on the corresponding items on both scales). Patient B’s psychiatrist gave her a total score of 20 on the Y-BOCS, and the research study clinician gave her a total score of 23 on the Y-BOCS-II.

Table 3.

Item scores on the Y-BOCS and Y-BOCS-II for Patient B

Time of assessment	March	April	May	June		March	April	May	June
Y-BOCS					Y-BOCS-II
1. Obsession-Time Spent	3	2	2	2	1. Obsession-Time Spent	3	2	2	2
2. Obsession-Interference	2	3	2	2	2. Obsession-Free Interval	3	2	2	3
3. Obsession-Distress	2	3	2	2	3. Obsession-Control	3	2	1	2
4. Obsession-Resistance	1	2	2	2	4. Obsession-Distress	2	3	2	2
5. Obsession-Control	2	2	1	2	5. Obsession-Interference	2	3	2	3
Obsession Sub Score Total	10	12	9	10	Obsession Sub Score Total	13	12	9	12
6. Compulsion-Time Spent	2	3	3	2	6. Compulsion-Time Spent	2	3	3	3
7. Compulsion-Interference	2	2	1	2	7. Compulsion-Resistance	2	3	3	3
8. Compulsion-Distress	2	3	2	3	8. Compulsion-Control	2	3	2	3
9. Compulsion-Resistance	2	2	2	2	9. Compulsion-Distress	2	3	4	4
10. Compulsion-Control	2	3	2	2	10. Compulsion-Interference	2	3	3	3
Compulsion Sub Score Total	10	13	10	11	Compulsion Sub Score Total	10	15	15	16
Y-BOCS Total Score	20	25	19	21	Y-BOCS-II Total Score	23	27	24	28

Open in a new tab

Figure 2. Y-BOCS and Y-BOCS-II Scores Over Time for Patient B.

Open in a new tab

During April 2020, the COVID-19 pandemic began spreading rapidly in the United States, and the threat of the pandemic heightened patient B’s level of distress related to her contamination concerns, making her compulsions less manageable. As she began to withdraw from public venues and isolate in the safety of her home, she spent less time occupied by obsessive thoughts, with longer periods symptom-free. However, she began experiencing severe distress from the intrusive thoughts and felt that they were much more disturbing and difficult to manage than before the pandemic (1 point increase to 3 on both scales for distress and interference due to obsessive thoughts items). In addition, she found it more difficult to resist the intrusive thoughts (1 point increase on Y-BOCS item 4). Her compulsions became more severe and constant, with an increase in time spent on handwashing and cleaning rituals to approximately 5 hours a day. During this time, she was only making “some effort” to resist the compulsions (1 point increase on Y-BOCS-II item 7 only); she had a stronger drive to perform compulsions, and she was sometimes unable to control them. The patient was engaging in time-consuming cleaning rituals more frequently and would take measures to avoid touching surfaces outside her home or use public restrooms. These changes were reflected in her Y-BOCS and Y-BOCS-II scores with a 25 and 27, respectively.

By the time patient B was reevaluated in May, 2020, she had become accustomed to a quarantined lifestyle and reported that she had noticed improvements in her OCD symptoms, especially in regard to compulsions. During her visits, she reported that the level of distress associated with obsessions and compulsions had decreased significantly, especially when only showering and doing laundry once a week. These “improvements” were accompanied by complaints from her husband about laundry piling up and deterioration of her personal hygiene. The patient endorsed the same amount of time spent occupied by obsessive thoughts, as well as obsession-free intervals, and she even stated she had much more control over the obsessions. As a result, the level of distress and interference caused by her intrusive thoughts decreased, especially while at home where contamination risks were minimal.

However, a meaningful divergence occurred between her psychiatrist and the research team when assessing Patient B’s compulsive behavior in May. While she reported no increase in time spent performing compulsive behaviors, when pressed by the research team using prompts on the Y-BOCS-II, she acknowledged that her avoidance behaviors had increased. She spent most of her time inside her house, and when venturing out to run errands, she wore disposable gloves, planned outings so they did not coincide with mealtimes, and even limited food and water intake before leaving to avoid having to use a public bathroom. She was still making some effort to resist the compulsions and reported being able to have a moderate amount of control over her typical behaviors. Her avoidance also manifested itself through increased neglect of household chores and routine hygiene, such as waiting a week between showers, avoiding cleaning floors and counters, and refusing to touch any objects from outside her house (eg, groceries). As such, her interference due to compulsions score remained elevated (severe) on the Y-BOCS-II. Due to increased avoidance of her OCD triggers, she reported to her psychiatrist that distress associated with her compulsions was more manageable, and that her overt behaviors were only interfering mildly in her life. As a result, her psychiatrist gave her a score of 2 on Y-BOCS item 8 (compulsions-distress) and a 1 on Y-BOCS item 7. However, she indicated to the research team that she would experience very severe anxiety that would be difficult to manage if she was not allowed to wear multiple layers of gloves any time she ventured outside or to avoid going to any public bathroom, all of which she considered “contaminated” despite appropriate pandemic precautions (a score of 4 on Y-BOCS-II item 9 Compulsion-distress). For example, the patient reported she would wear 3 layers of gloves and a mask and that she would set a 15-minute timer just to walk to her mailbox to avoid any potential exposure to contaminates outside her house. Although this 15-minute time limit was based on the Center for Disease Control and Prevention guidelines for avoiding close contact with individuals infected with the novel coronavirus,²⁸ the context in which the patient was applying it was inappropriate and demonstrated increased active avoidance measures. The final total scores for the visit in May were a 19 on the Y-BOCS and 24 on the Y-BOCS-II.

During June, 2020, Patient B’s avoidance behaviors substantially increased to the point where she was engaging in passive and active avoidance behaviors regularly in nearly all areas of her life. She was reluctant to engage in any activity that would trigger time-consuming cleaning or handwashing rituals, including doing the dishes, laundry, or showering. When assessed by her psychiatrist, she continued to report only moderate distress and interference from obsessions, as well as reductions in time spent on her overt compulsive behaviors (back to around 2 hours a day; decrease from a score of 3 to 2 on Y-BOCS item 6), despite complaints from her husband about neglect of household chores. However, she did report that her obsessive thoughts were occurring more frequently, about once every couple of hours, and were a little harder to control as the pandemic continued (increase of 1 point on Y-BOCS item 5 and Y-BOCS-II item 2). Her psychiatrist did note that her distress would be fairly severe if she could not wear her gloves in public (score of 3 on Y-BOCS item 8) and that this behavior was causing some increased interference (score of 2 on Y-BOCS item 7), but overall the psychiatrist felt that the patient was doing well.

Her assessment by the research team told a different story, with Patient B scoring the highest on her compulsion subscales since March. When factoring in time spent wearing gloves, meticulously planning outings, and ritualizing her eating schedules, it was determined she spent about 5 hour per day performing compulsions. In addition, she endorsed having only some control over these behaviors, which would result in very severe distress if these avoidance tactics were prevented (sustained score of 4 on Y-BOCS-II item 9). It was also clear that these measures had caused significant impairment in one or more domains of functioning. As they were employed to prevent both obsessions and triggers for compulsions, she scored a 3 on both Y-BOCS-II items 5 and 10. Overall total scores for these visits were 21 on the Y-BOCS and 28 on the Y-BOCS-II.

CASE C. PATIENT WITH MILD/MODERATE SYMPTOMS ASSESSED WHILE RECEIVING ERP THERAPY AT THE CLINIC

Background

Patient C was a 23-year-old Hispanic male with onset of OCD symptoms at approximately 15 years of age. He was taking 40 mg fluoxetine 4 times daily and had just begun a course of ERP. His prominent obsessions involved intrusive taboo thoughts regarding sacrilege and sex, including unwanted sexual thoughts about family members and fear he would offend God if he thought about symbols or numbers that were considered satanic. His compulsions centered on performing mental rituals to neutralize unwanted thoughts, primarily repeating prayers silently to himself. Occasionally, he engaged in overt compulsions by genuflecting (ie, kneeling or making the “sign of the cross”) repeatedly when obsessions were more intense. While his intrusive thoughts were distracting at times and could occur frequently, his compulsions were completed quickly and were not generally noticeable to outside observers. The patient did not engage in any type of avoidance behaviors to try to minimize the intrusive thoughts. His obsessions and compulsions mildly interfered with his social life; his performance at work was not impaired. His insight was good, and he had no history of psychotic symptoms or delusional thinking. Patient C was assessed throughout his course of ERP using the Y-BOCS-II with the addition of Y-BOCS item 4, so that the back-coding method could be used to obtain scores on both measures.

Treatment

Table 4 shows Patient C’s Y-BOCS and Y-BOCS-II obsession item scores for each visit, with the resistance against obsessions items and obsession free-interval items highlighted to emphasize the primary difference between the measures in this example. As all of the patient’s symptoms fell within the mild to moderate range, and the back-coding method was employed, all other scores (including compulsion items) remained the same across the Y-BOCS and Y-BOCS-II. Figure 3 illustrates Patient C’s total Y-BOCS and Y-BOCS-II scores over time.

Table 4.

Obsession item scores on the Y-BOCS and Y-BOCS-II for Patient C

Time of assessment	BL	2 wk	4 wk	6 wk	8 wk	10 wk	12 wk		BL	2 wk	4 wk	6 wk	8 wk	10 wk	12 wk
Y-BOCS								Y-BOCS-II
1. Obsession-Time Spent	3	3	2	2	2	2	2	1. Obsession-Time Spent	3	3	2	2	2	2	2
2. Obsession-Interference	2	2	2	1	1	1	1	2. Obsession-Free Interval	3	3	3	2	2	2	1
3. Obsession-Distress	2	3	2	2	3	2	2	3. Obsession-Control	3	3	3	2	3	2	1
4. Obsession-Resistance	2	2	1	1	1	1	1	4. Obsession-Distress	2	3	2	2	3	2	2
5. Obsession-Control	3	3	3	2	3	2	1	5. Obsession-Interference	2	2	2	1	1	1	1
Obsession Sub Scale Total	12	13	10	8	10	8	7	Obsession Sub Scale Total	13	14	12	9	11	9	7
Compulsion Sub Score Total	12	13	10	10	12	7	6	Compulsion Sub Scale Total	12	13	10	10	12	7	6
Y-BOCS Total Score	24	26	20	18	22	15	13	Y-BOCS-II Total Score	25	27	22	19	23	16	13

Open in a new tab

The resistance against obsessions items and obsession free-interval items are highlighted to emphasize the primary difference between the 2 measures. As all of the patient’s symptoms fell within the mild to moderate range, and the back-coding method was employed, all other scores (including compulsion items) remained the same across the Y-BOCS and Y-BOCS-II and thus are not shown.

Figure 3. Y-BOCS and Y-BOCS-II Scores Over Time for Patient C.

Open in a new tab

During Patient C’s initial session, he received a baseline score of 24 on the Y-BOCS and a 25 on the Y-BOCS-II. The patient met with his therapist for ERP sessions once a week for 1 hour. Two weeks into therapy, he had difficulty adjusting to therapeutic exposures, and he experienced elevated distress associated with obsessions and compulsions, resulting in an increase from a score of 2 (moderate distress) to a score of 3 (severe distress) on these items. The total scores for this visit were a 26 on the Y-BOCS and a 27 on the Y-BOCS-II.

During his week 4 visit, Patient C’s scores showed clear improvements. The time spent on obsessive thoughts decreased slightly to about 2.5 hours a day. Control over obsessions remained the same, but the distress caused by the thoughts was reduced, with ratings going down from a score of 3 (severe) to a score of 2 (moderate) on Y-BOCS-II item 4. There was also a noticeable change in the patient’s ability to understand and “resist” his obsessions by letting them happen and not struggling against them. Though he was not often successful at controlling the thoughts, this effort to apply this ERP technique most of the time resulted in a decrease from a score of 2 to a score of 1 on Y-BOCS item 4. While the time spent on compulsive behaviors remained around 2 hours a day, the patient’s ability to resist the compulsions improved, as did the anxiety associated with them. As such, his scores dropped to a 2 (moderate effort to resist/moderate distress) on both of these compulsion subscales. The patient’s overall scores for this visit were a 20 on the Y-BOCS and a 22 on the Y-BOCS-II.

These improvements continued 6 weeks into treatment, with Patient C experiencing additional gains regarding his obsessions. He was now able to go up to 4 hours free of intrusions while engaging in recreational activities, scoring a 2 (moderately long periods) on Y-BOCS-II item 2. He also reported an increased ability to stop or ignore obsessions (often, with some effort and concentration), with obsessions only mildly interfering with social/occupational activities. The total scores during this visit were 18 and 19 on the Y-BOCS and Y-BOCS-II, respectively.

Patient C came to his 8 week visit feeling distressed from having recently been laid-off from his job, resulting in a spike in his obsessive-compulsive symptoms. It became noticeably more difficult for him to control/dismiss the intrusive thoughts as he worried that he lost his job because he had done something to offend God. He reported having some control, only sometimes being able to stop or ignore the obsessions (now a score of 3 on Y-BOCS-II item 3), as well as a surge in distress (sometimes severe and difficult to manage) caused by the intrusive thoughts. This life stressor also affected the degree of control and distress caused by his compulsive behaviors. His final scores increased by 4 points during this visit, with a 22 on Y-BOCS and a 23 on Y-BOCS-II.

A week after losing his job, Patient C applied for and received unemployment benefits, and while he remained concerned about his financial situation, the unemployment benefits provided some stability while he continued searching for new employment. One week after receiving unemployment benefits and now 10 weeks into ERP, he reported doing much better. Both the amount of control and distress related to obsessions returned to moderate/manageable levels. In addition, the patient showed improvements on all of the compulsion subscales, as he had been working hard to conquer his behaviors. He was able to regain a moderate degree of control and reported only a moderate level of distress associated with compulsions. He was now trying to resist compulsions almost all of the time and reported spending less than 1 hour a day performing the behaviors. Consequently, his compulsions only caused mild/slight interference.

Three months into ERP, Patient C continued to show steady improvements and increased mastery over all of his OCD symptoms. He reported only experiencing intrusive thoughts upon waking in the morning and when getting ready for bed at night, with the ability to go all day (more than 8 hours) free of obsessions (score of 1 on Y-BOCS-II item 2). His degree of control over the obsessions and compulsions also improved significantly, as he was usually able to stop or ignore obsessions and resist compulsions. Overall, he scored a 13 (now within the mild range of symptoms) at this visit on both the Y-BOCS (a 46% decrease from baseline) and Y-BOCS-II (a 48% decrease from baseline).

DISCUSSION

This article described 3 scenarios in which utilization of the enhanced attributes of the Y-BOCS-II proved essential in ascertaining a more accurate clinical picture of patients with OCD. Specifically, in OCD patients with extreme symptom severity, or those presenting with significant avoidance, raters are better equipped to detect and evaluate fine-grained changes in symptoms with the improved scoring range of the Y-BOCS-II. Case A demonstrates variability and symptom improvement within the extreme symptom range, captured by the Y-BOCS-II but not by the Y-BOCS, while Case B demonstrates how the Y-BOCS-II provides a more comprehensive and stable assessment over time of compulsions that are complicated by avoidance behaviors. Finally, Case C exhibits the parallel trend of Y-BOCS and Y-BOCS-II scores in a patient with moderate obsessive-compulsive symptoms without significant avoidance.

Symptom variability and improvement can be difficult to detect in severely ill patients; a common problem among groups using neuromodulation or investigational approaches designed specifically for patients with treatment-resistant cases with more severe presentations.^14,15 Utilizing the expanded 6-point score range is crucial in uncovering upper range mobility in these patients. In these cases, symptoms may be so severe and disruptive that Y-BOCS and Y-BOCS-II scores are almost maxed out. This can be driven by multiple factors, including interference with life (ie, “housebound” and/or dependent on other for activities of daily living), symptom duration (ie, “near constant”), and associated distress. In addition, resistance and control of OCD symptoms mediates functional disability, with patients who make little effort to resist or control their symptoms experiencing greater impairment.²⁹ In situations in which patients are unable to resist or control obsessions or compulsions, they may instead be relying heavily upon accommodation from family members while retreating from routine activities. For patients this disabled, it is important to recognize and measure small, yet meaningful gains in motivation and engagement with life, even if symptom severity and intensity remain unchanged. These gains in quality of life, although sometimes independent of reductions in OCD symptom severity, can be significant and enduring, representing meaningful change in the clinical state of chronically ill patients.³⁰ These modest improvements can be reflected in the Y-BOCS-II by decreases in scores from 5 to 4 on interference items, while still presenting these patients as severely impaired, whereas their scores may remain relatively unchanged on the Y-BOCS. In this way, the Y-BOCS-II provides a unique metric that may help clinicians determine if and when a treatment program is producing beneficial improvements in severe cases and may be worth continuing versus seeking alternative treatment.

In patients experiencing constant symptom intrusions in excess of 12 hours a day, the expanded scoring range can also effectively capture notable decreases in symptom duration and related distress. In these cases, a drop in symptom duration of 3–4 hours (certainly a meaningful change within the moderate range of the scale), is registered as a change on the Y-BOCS-II, while their Y-BOCS scores may remain maxed out and unchanged from baseline. Conversely, increases in severity within this extreme symptom range can also be captured more effectively by the Y-BOCS-II, with increases from 4 to 5 on relevant items. While these dips in severity may also be captured by the Y-BOCS, they are more prominently reflected in the Y-BOCS-II without hitting the ceiling of the scale. This ability to identify fluctuations within the expanded “extreme” range is especially important for identifying treatment response or relapse, especially among extremely ill patients.

It is also important to mention the impact replacing Y-BOCS item 4 (resistance against obsessions) with Y-BOCS item 2 (obsession-free interval) has on patient scores. Unless actively involved in and benefiting from treatment, resistance against obsessions scores may remain relatively stable, especially in extremely impaired patients who are unable to resist obsessive thoughts. In contrast, these patients may experience meaningful fluctuations in their symptom-free interval, translating to more noticeable increases and decreases in Y-BOCS-II scores. The shift from constant intrusions to sustained symptom-free intervals is certainly more distinct and meaningful than the more ambiguous assessment of resistance against obsessions. When using the back-coding method, ratings that fall within the mild to moderate symptom range on the Y-BOCS-II will translate directly to their Y-BOCS counterparts, with the exception of item 2 (obsession-free interval). As a result, Y-BOCS and Y-BOCS-II scores in this range will typically parallel each other within 1–2 points and will only converge onto the same total score when the ratings on Y-BOCS item 4 and Y-BOCS-II item 2 are exactly the same (eg, at Patient C’s last visit).

The proper detection and appraisal of avoidance behaviors is also essential in outlining a patient’s true clinical presentation, as well as the course of symptoms amid changing life stressors and environmental factors. It is especially important for raters to identify when compulsions transition into ritualized avoidance so they can recognize “false improvements” that may occur when patients experience decreases in distress and time spent on compulsive behaviors due to avoidance. Patients presenting with highly ingrained avoidance behaviors may report their OCD is relatively under control, despite a lack of social and professional engagement outside their house. When isolated at home and avoiding contact with specific triggers, patients may perceive manageable levels of OCD distress with little overall time spent engaging in overt rituals. Indeed, patients may experience genuine reductions in distress and interference related to intrusive thoughts when avoiding OCD triggers, which can be meaningful and important to capture, regardless of the circumstances. However, by probing beyond established or overt compulsive behaviors using prompts in the Y-BOCS-II, assessors can identify active avoidance measures (eg, wearing gloves, planning outings, limiting food intake) and account for increased distress and interference related to these behaviors. In addition, passive avoidance of obsessive or compulsive triggers that translate into measurable neglect of responsibilities can be incorporated systematically into the Y-BOCS-II interference items via more descriptive rating anchors. While the Y-BOCS has sensitivity to these domains, mainly with regard to their impact on distress and control, the Y-BOCS-II has more capacity to interpret the overall impact avoidance plays in terms of time spent, associated distress, and interference with life.

When assessing most patients with OCD with moderate symptom severity, the Y-BOCS-II maintains strong congruence with the Y-BOCS, especially when using the back-coding method. Even with separate administrations, overall Y-BOCS and Y-BOCS-II scores should remain within about 1 to 4 points of each other in a majority of cases in which extreme symptom severity and avoidance are not extenuating factors. Indeed, this can be seen at various points in all 3 of the cases presented here. This gap in final scores between measures is due in large part to the replacement of Y-BOCS item 4 (resistance against obsessions) with Y-BOCS-II item 2 (obsession-free interval), which tends to produce higher scores with more variability on the Y-BOCS-II. The expansion of the moderate-range ratings on Y-BOCS-II items for control (items 3 and 8) and resistance against compulsions (item 7) can also account for differences in final scores on both measures. By allowing the rater to specify between “moderate” resistance/control (score of 2) and “some” resistance/control (score of 3) on these items, the Y-BOCS-II may result in a final score that is up to 3 points higher than the Y-BOCS, yet still consistent in terms of severity for these patients. This expansion of the middle-range ratings on these items provides increased sensitivity to changes within the moderate range, while still producing scores that appropriately reflect moderate symptom severity.

While this article reinforces the rationale for the development and subsequent use of the Y-BOCS-II, and the child counterpart, the Children’s Y-BOCS-II (which was developed for similar reasons to the Y-BOCS-II),³¹ widespread adoption of the Y-BOCS-II as the standard outcome measure will require additional steps. First, signal detection^17,32 and consensus reports³³ have delineated cutoffs for treatment response and severity metrics for the Y-BOCS but not the Y-BOCS-II. Further work is needed to establish the same treatment response and severity criteria for the Y-BOCS-II. Second, training protocols to ensure high fidelity administration of Y-BOCS-II prompts and new items will require dissemination. On balance, this presents as a positive opportunity as Y-BOCS administration may be affected by rater variation (eg, how avoidance was integrated into symptom ratings). Third, many scales have been developed based on the Y-BOCS to assess related constructs (eg, body dysmorphic disorder, olfactory reference syndrome), and thus these scales may benefit from corresponding revisions. Although further research is necessary to continue advancing the Y-BOCS-II as a future gold-standard assessment tool for OCD, there is a meaningful advantage to its widespread adoption; namely, that it provides a more nuanced method of assessing OCD severity while retaining meaningful congruence with Y-BOCS scoring.

Acknowledgments:

This work was supported by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health (NIH) under award number 1UH3NS100549-01, the National Institute of Mental Health under award number 1RF1MH121371, and the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health under Award Number P50HD103555 for use of the Clinical and Translational Core facilities. Opinions expressed in this article are those of the authors and do not necessarily reflect those of NIH.

Footnotes

Dr. Goodman received an honorarium from Biohaven Pharmaceuticals. He receives research grant support from NIH, the McNair Foundation, and Biohaven Pharmaceuticals. He receives donated medical devices from Medtronic. Dr. Storch receives book royalties from Elsevier, Jessica Kingsley, American Psychological Association, Springer, Lawrence Erlbaum, and Wiley. He is a consultant for Biohaven and Brainsway. He holds stock in NView. He receives grant support from NIH, Ream Foundation, Texas Higher Education Coordinating Board, Greater Houston Community Foundation. The remaining authors declare no conflicts of interest.

REFERENCES

1.Goodman WK, Price LH, Rasmussen SA, et al. The Yale-Brown Obsessive Compulsive Scale. I. Development, use, and reliability Arch Gen Psychiatry. 1989;46:1006–1011. [DOI] [PubMed] [Google Scholar]
2.Deacon BJ, Abramowitz JS. The Yale-Brown Obsessive Compulsive Scale: factor analysis, construct validity, and suggestions for refinement. J Anxiety Disord. 2005;19:573–585. [DOI] [PubMed] [Google Scholar]
3.Frost RO, Steketee G, Krause MS, et al. The relationship of the Yale-Brown Obsessive Compulsive Scale (YBOCS) to other measures of obsessive compulsive symptoms in a nonclinical population. J Pers Assess. 1995;65:158–168. [DOI] [PubMed] [Google Scholar]
4.Goodman WK, Price LH, Rasmussen SA, et al. The Yale-Brown Obsessive Compulsive Scale. II. Validity. Arch Gen Psychiatry. 1989;46:1012–1016. [DOI] [PubMed] [Google Scholar]
5.Kim SW, Dysken MW, Kuskowski M. The Yale-Brown Obsessive-Compulsive Scale: a reliability and validity study. Psychiatry Res. 1990;34:99–106. [DOI] [PubMed] [Google Scholar]
6.Foa EB, Liebowitz MR, Kozak MJ, et al. Randomized, placebo-controlled trial of exposure and ritual prevention, clomipramine, and their combination in the treatment of obsessive-compulsive disorder. Am J Psychiatry. 2005;162:151–161. [DOI] [PubMed] [Google Scholar]
7.Storch EA, Merlo LJ, Lehmkuhl H, et al. Cognitive-behavioral therapy for obsessive-compulsive disorder: a non-randomized comparison of intensive and weekly approaches. J Anxiety Disord. 2008;22:1146–1158. [DOI] [PubMed] [Google Scholar]
8.McKay D, Neziroglu F, Stevens K, et al. The Yale-Brown Obsessive-Compulsive Scale: confirmatory factor analytic findings. J Psychopathol Behav Assess. 1998;20:265–274. [Google Scholar]
9.Moritz S, Meier B, Kloss M, et al. Dimensional structure of the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Psychiatry Res. 2002;109:193–199. [DOI] [PubMed] [Google Scholar]
10.Rapp AM, Bergman RL, Piacentini J, et al. Evidence-based assessment of obsessive-compulsive disorder. J Cent Nerv Syst Dis. 2016;8:13–29. [DOI] [PMC free article] [PubMed] [Google Scholar]
11.Arrindell WA, de Vlaming IH, Eisenhardt BM, et al. Cross-cultural validity of the Yale-Brown Obsessive Compulsive Scale. J Behav Ther Exp Psychiatry. 2002;33:159–176. [DOI] [PubMed] [Google Scholar]
12.McKay D, Danyko S, Neziroglu F, et al. Factor structure of the Yale-Brown Obsessive-Compulsive Scale: a two dimensional measure. Behav Res Ther. 1995;33:865–869. [DOI] [PubMed] [Google Scholar]
13.Storch EA, Shapira NA, Dimoulas E, et al. Yale-Brown Obsessive Compulsive Scale: the dimensional structure revisited. Depress Anxiety. 2005;22:28–35. [DOI] [PubMed] [Google Scholar]
14.Denys D, Mantione M, Figee M, et al. Deep brain stimulation of the nucleus accumbens for treatment-refractory obsessive-compulsive disorder. Arch Gen Psychiatry. 2010;67:1061–1068. [DOI] [PubMed] [Google Scholar]
15.Storch EA, Goodman WK. Response to: Optimizing DBS stimulation parameters in obsessive-compulsive disorder. Neuromodulation. 2021;24:400. [DOI] [PubMed] [Google Scholar]
16.McGuire JF, Storch EA, Lewin AB, et al. The role of avoidance in the phenomenology of obsessive-compulsive disorder. Compr Psychiatry. 2012;53:187–194. [DOI] [PubMed] [Google Scholar]
17.Storch EA, Lewin AB, De Nadai AS, et al. Defining treatment response and remission in obsessive-compulsive disorder: a signal detection analysis of the Children’s Yale-Brown Obsessive Compulsive Scale. J Am Acad Child Adolesc Psychiatry. 2010;49:708–717. [DOI] [PubMed] [Google Scholar]
18.Castro-Rodrigues P, Camacho M, Almeida S, et al. Criterion validity of the Yale-Brown Obsessive-Compulsive Scale Second Edition for diagnosis of obsessive-compulsive disorder in adults. Front Psychiatry. 2018;9:431. [DOI] [PMC free article] [PubMed] [Google Scholar]
19.Zhang CC, Gong H, Zhang Y, et al. Development and psychometric evaluation of the Mandarin Chinese version of the Yale-Brown Obsessive-Compulsive Scale–Second Edition. Braz J Psychiatry. 2019;41:494–498. [DOI] [PMC free article] [PubMed] [Google Scholar]
20.Hiranyatheb T, Saipanish R, Lotrakul M. Reliability and validity of the Thai version of the Yale-Brown Obsessive Compulsive Scale–Second Edition in clinical samples. Neuropsychiatr Dis Treat. 2014;10:471–477. [DOI] [PMC free article] [PubMed] [Google Scholar]
21.Storch EA, Larson MJ, Price LH, et al. Psychometric analysis of the Yale-Brown Obsessive-Compulsive Scale Second Edition Symptom Checklist. J Anxiety Disord. 2010;24:650–656. [DOI] [PubMed] [Google Scholar]
22.Storch EA, Rasmussen SA, Price LH, et al. Development and psychometric evaluation of the Yale-Brown Obsessive-Compulsive Scale–Second Edition. Psychol Assess. 2010;22:223–232. [DOI] [PubMed] [Google Scholar]
23.Wu MS, McGuire JF, Horng B, et al. Further psychometric properties of the Yale-Brown Obsessive Compulsive Scale–Second Edition. Compr Psychiatry. 2016;66:96–103. [DOI] [PubMed] [Google Scholar]
24.Foa EB, Elna Y, Tracey KL. Exposure and Response (Ritual) Prevention for Obsessive-Compulsive Disorder: Therapist Guide. Oxford: Oxford University Press; 2012. [Google Scholar]
25.Selles RR, Højgaard DRMA, Ivarsson T, et al. Avoidance, insight, impairment recognition concordance, and cognitive-behavioral therapy outcomes in pediatric obsessive-compulsive disorder. J Am Acad Child Adolesc Psychiatry. 2020;59:650–659.e2. [DOI] [PMC free article] [PubMed] [Google Scholar]
26.Starcevic V, Berle D, Brakoulias V, et al. The nature and correlates of avoidance in obsessive-compulsive disorder. Aust N Z J Psychiatry. 2011;45:871–879. [DOI] [PubMed] [Google Scholar]
27.Wheaton MG, Gershkovich M, Gallagher T, et al. Behavioral avoidance predicts treatment outcome with exposure and response prevention for obsessive-compulsive disorder. Depress Anxiety. 2018;35:256–263. [DOI] [PMC free article] [PubMed] [Google Scholar]
28.United States Department of Health and Human Services, Centers for Disease Control and Prevention. Covid-19 Case Investigation and Contact Tracing Guidance, 2021. Available at: www.cdc.gov/coronavirus/2019-ncov/php/contact-tracing/contact-tracing-plan/appendix.html#:~:text=Close%20Contact,-Definition&text=Someone%20who%20has%20been%20within,15%20minutes%20in%20one%20day.Accessed May 4, 2021.
29.Storch EA, Abramowitz JS, Keeley M. Correlates and mediators of functional disability in obsessive-compulsive disorder. Depress Anxiety. 2009;26:806–813. [DOI] [PubMed] [Google Scholar]
30.Alonso P, Cuadras D, Gabriëls L, et al. Deep brain stimulation for obsessive-compulsive disorder: a meta-analysis of treatment outcome and predictors of response. PLoS One. 2015;10:e0133591. [DOI] [PMC free article] [PubMed] [Google Scholar]
31.Storch EA, McGuire JF, Wu MS, et al. Development and psychometric evaluation of the Children’s Yale-Brown Obsessive-Compulsive Scale Second Edition. J Am Acad Child Adolesc Psychiatry. 2019;58:92–98. [DOI] [PMC free article] [PubMed] [Google Scholar]
32.Tolin DF, Abramowitz JS, Diefenbach GJ. Defining response in clinical trials for obsessive-compulsive disorder: a signal detection analysis of the Yale-Brown Obsessive Compulsive Scale. J Clin Psychiatry. 2005;66:1549–1557. [DOI] [PubMed] [Google Scholar]
33.Mataix-Cols D, Fernández de la Cruz L, Nordsletten AE, et al. Towards an international expert consensus for defining treatment response, remission, recovery and relapse in obsessive-compulsive disorder. World Psychiatry. 2016;15:80–81. [DOI] [PMC free article] [PubMed] [Google Scholar]