Yale – Brown Obsessive Compulsive Scale (Y-BOCS)

Abstract

The Yale–Brown Obsessive Compulsive Scale (Y-BOCS) is widely recognized as the international gold-standard clinician-administered instrument for assessing the presence, phenomenology, and severity of obsessive-compulsive symptoms in patients with obsessive-compulsive disorder (OCD). Originally developed in 1989 by Wayne K. Goodman and colleagues, the core instrument isolates symptom severity from specific symptom content across two primary domains: obsessions and compulsions. The core severity scale comprises 10 clinician-rated items evaluated along five distinct clinical dimensions: time spent, interference with functioning, subjective distress, active resistance, and perceived degree of control over symptoms. Each item is scored on a 5-point Likert-type severity continuum ranging from 0 (no symptoms) to 4 (extreme/incapacitating), yielding an Obsessions Subtotal (range 0–20), a Compulsions Subtotal (range 0–20), and a composite Total Severity Score (range 0–40). Psychometric evaluations consistently demonstrate that the Y-BOCS exhibits excellent inter-rater reliability (intraclass correlation coefficients typically exceeding .85 to .95), strong internal consistency (Cronbach’s alpha ranging from .87 to .91), and robust convergent validity against other measures of obsessive-compulsive symptom severity. Furthermore, the scale exhibits notable sensitivity to therapeutic change, establishing it as the standard primary outcome benchmark in clinical trials of psychopharmacological agents, cognitive-behavioral therapy, exposure and response prevention, and neuromodulation therapies. This comprehensive paper provides a granular evaluation of the Y-BOCS, detailing its historical context, dimensional constructs, structural validity, factor structure, psychometric properties, and administrative protocols.

Keywords

Yale–Brown Obsessive Compulsive Scale, Y-BOCS, obsessive-compulsive disorder, psychometrics, clinical interview, symptom severity, convergent validity, inter-rater reliability, outcome measurement, exposure and response prevention

Authors

The Yale–Brown Obsessive Compulsive Scale was created through a multi-institutional collaborative effort led by researchers in the Department of Psychiatry at the Yale University School of Medicine (New Haven, Connecticut) and the Brown University School of Medicine (Providence, Rhode Island). The principal investigative team comprised:

• Wayne K. Goodman, M.D. — Professor and Chair of Psychiatry, Baylor College of Medicine (formerly affiliated with Yale University School of Medicine). Dr. Goodman served as the principal designer of the scale and primary author of the seminal validation studies.
• Lawrence H. Price, M.D. — Professor of Psychiatry and Human Behavior, Brown University School of Medicine; Clinical Director at Butler Hospital (formerly Associate Professor of Psychiatry, Yale University School of Medicine).
• Steven A. Rasmussen, M.D. — Mary E. Phillips Professor and Chair of the Department of Psychiatry and Human Behavior, Brown University Alpert Medical School; Butler Hospital.
• Carolyn M. Mazure, Ph.D. — Norma Weinberg Spungen and Joan Levin Spungen Professor of Psychiatry and Psychology, Yale School of Medicine.
• Pedro L. Delgado, M.D. — Professor of Psychiatry and behavioral science leader (formerly at Yale University).
• George R. Heninger, M.D. — Professor Emeritus of Psychiatry, Yale University School of Medicine.
• Dennis S. Charney, M.D. — Anne and Joel Ehrenkranz Dean, Icahn School of Medicine at Mount Sinai (formerly at Yale University).

Initial correspondence regarding the development of the instrument was coordinated through the Clinical Neuroscience Research Unit, Connecticut Mental Health Center, Department of Psychiatry, Yale University School of Medicine.

Purpose

The Yale–Brown Obsessive Compulsive Scale was designed to address a critical methodological limitation in psychiatric research during the late 1980s: the lack of a standardized, reliable, and valid instrument dedicated specifically to tracking the clinical severity of obsessive-compulsive symptoms independently of the qualitative thematic content or the specific typology of the obsessions and compulsions. Prior to the Y-BOCS, clinicians and clinical investigators relied on broad psychiatric rating scales, such as the Comprehensive Psychopathological Rating Scale or general anxiety inventories, which confounded the number of distinct rituals or intrusive thoughts with the actual severity, impairment, and psychological burden imposed by those symptoms.

The foundational purpose of the Y-BOCS is not to establish a categorical diagnostic determination of OCD, nor is it intended to serve as a self-report screening tool. Rather, it is designed as a semi-structured, clinician-administered assessment intended to quantify obsessive-compulsive symptom severity over a discrete observational window (typically the preceding 7 days). It is designed to be completed after the clinician has conducted an exhaustive qualitative evaluation—most commonly facilitated by the accompanying Y-BOCS Symptom Checklist—identifying the patient’s specific baseline obsessions (e.g., contamination, aggressive impulses, symmetry/order, somatic preoccupations, religious scrupulosity) and compulsions (e.g., cleaning/washing, checking, repeating, counting, ordering/arranging, mental rituals).

In clinical practice, the Y-BOCS serves multiple interrelated functions:

• Quantification of Baseline Severity: Establishing a calibrated benchmark that places the individual along an empirically validated continuum from subclinical manifestation (scores 0–7) to extreme, incapacitating illness (scores 32–40).
• Treatment Response Monitoring: Tracking dynamic symptomatic trajectories over the course of cognitive-behavioral therapies (particularly Exposure and Response Prevention [ERP]), selective serotonin reuptake inhibitor (SSRI) pharmacotherapy, augmentation regimens, or neurosurgical interventions (such as deep brain stimulation).
• Operationalization of Treatment Response and Remission: Establishing empirical definitions in clinical research. In major regulatory trials, a 25% to 35% reduction in the total Y-BOCS score combined with a Clinical Global Impressions–Improvement (CGI-I) rating of “much improved” or “very much improved” is typically defined as a clinically meaningful response, while a post-treatment score of ≤ 12 (or in stricter trials, ≤ 8) denotes partial or full symptom remission.
• Phenotypic Disentanglement: Separating the severity of cognitive intrusions (obsessions) from behavioral or mental rituals (compulsions), allowing clinicians to identify dissociations in treatment response between cognitive and motoric/behavioral components.

Psychological Construct

The primary psychological construct operationalized by the Y-BOCS is obsessive-compulsive symptom severity. Crucially, the architectural framework of the scale conceptualizes severity not as a function of the mere variety, idiosyncratic content, or bizarre quality of an individual’s obsessions and compulsions, but rather as an aggregate construct measured across five distinct psychometric parameters applied symmetrically across both symptom domains.

1. Temporal Burden (Time Spent / Duration)

The temporal dimension evaluates the absolute and relative duration of waking consciousness consumed by obsessive thoughts or compulsive rituals. For obsessions (Item 1), the interviewer assesses the cumulative frequency and persistence of cognitive intrusions, ranging from brief, occasional episodes (less than 1 hour per day) to constant, continuous intrusive rumination (greater than 8 hours per day). For compulsions (Item 6), it measures the cumulative hours dedicated to executing repetitive behavioral or mental acts, distinguishing between brief, punctuated rituals and near-incessant performance that paralyzes the patient’s daily routine.

2. Functional Interference (Impairment in Role Functioning)

This dimension measures the degree to which intrusive cognitions (Item 2) or ritualistic behaviors (Item 7) interrupt, compromise, or outright prevent the fulfillment of normative social, occupational, educational, and interpersonal roles. The scale evaluates concrete functional consequences, such as occupational absenteeism, delayed social milestones, operational inefficiency, and avoidance behaviors directly linked to symptom containment. Ratings advance from slight, non-debilitating interference to complete, catastrophic psychosocial incapacitation.

3. Subjective Distress (Internal Affective Burden)

The distress dimension measures the affective toll imposed by the disorder. For obsessions (Item 3), this construct captures the level of anxiety, agitation, disgust, or existential terror evoked directly by the intrusive thoughts, images, or urges. For compulsions (Item 8), the dimension is operationalized through a unique counterfactual assessment: the clinician evaluates the magnitude of distress and panic that the patient would experience if they were actively thwarted or prevented from executing their compulsive rituals, as well as the distress experienced while carrying out the compulsions.

4. Active Resistance (Effort to Suppress or Deflect)

Resistance captures the active cognitive and behavioral effort deployed by the patient to challenge, suppress, disregard, or neutralize obsessions (Item 4) or to refrain from enacting compulsions (Item 9). Paradoxically, within the original psychometric design of the scale, higher scores reflect less resistance (surrender to the symptoms). Patients who completely submit to their intrusive thoughts or yield immediately to compulsive impulses receive higher severity ratings, whereas those who engage in vigorous, continuous attempts to resist are rated lower on this specific item, reflecting preserved psychological agency.

5. Perceived Degree of Control (Efficacy of Divergence and Termination)

The final core dimension appraises the patient’s perceived locus of control and practical success in halting, diverting, or dismissing obsessive thoughts (Item 5), or terminating and preventing compulsive motor or mental rituals (Item 10). This construct assesses cognitive flexibility, voluntary behavioral inhibition, and the subjective sense of self-efficacy in overcoming symptom-related impulses. Complete lack of control corresponds to involuntary, autonomous symptom expression that cannot be interrupted even momentarily.

Theoretical Framework

The Y-BOCS is grounded in an integrative model drawing from cognitive-behavioral psychopathology and neuropsychiatric paradigms of obsessive-compulsive spectrum conditions. The instrument’s conceptualization reflects major developments in cognitive theory, most notably the appraisal models formulated by Paul Salkovskis, Stanley Rachman, and David A. Clark.

The Cognitive-Behavioral Formulation

Cognitive formulations posit that intrusive thoughts, images, and impulses are ubiquitous across non-clinical populations; the pathogenesis of OCD occurs when these normative intrusions are appraised as highly meaningful, dangerous, or indicative of personal responsibility for catastrophic harm (Salkovskis, 1985). This catastrophic misappraisal generates profound subjective distress (measured by Item 3). In response, the individual initiates deliberate neutralization strategies—overt behavioral compulsions or covert mental rituals—aimed at expelling the intrusion, averting the perceived threat, or reducing discomfort.

While these compulsions provide immediate, negative-reinforcement-driven distress reduction, they ultimately prevent the natural disconfirmation of feared catastrophes and maintain obsessive vulnerability. The Y-BOCS architecture captures this cyclical dynamic: Item 8 explicitly probes the catastrophic distress anticipated upon ritual prevention, directly evaluating the strength of this negative reinforcement mechanism.

The Neuropsychiatric and Circuit-Based Paradigm

Concurrently, the Y-BOCS was structured by Goodman and colleagues within a neuropsychiatric framework that views OCD as a neurobiological disorder characterized by dysfunction within cortico-striato-thalamo-cortical (CSTC) loops. Hyperactivity within the orbitofrontal cortex, anterior cingulate cortex, and ventral striatum is associated with failure of behavioral inhibition and the continuous generation of internal “error signals” or feelings of incompleteness (“not-just-right” experiences). By assessing parameters such as “time spent” and “perceived control,” the Y-BOCS operationalizes the failure of neurobiological gating mechanisms that normally terminate intrusive thoughts and allow the transition to other behavioral programs.

Separation of Form, Theme, and Intensity

A fundamental theoretical premise of the Y-BOCS is the structural dissociation between symptom typology and symptom severity. Classical psychometrics frequently conflated thematic heterogeneity with pathological severity. A patient exhibiting five distinct washing, checking, and ordering rituals was often scored as more severely impaired than a patient who exhibited a single, all-consuming checking ritual. The Y-BOCS theoretical framework corrected this fallacy by establishing that the dimensional parameters of severity—time, interference, distress, resistance, and control—represent the underlying latent severity variable, invariant across diverse symptom themes.

Validity

The psychometric validity of the Y-BOCS has been verified in psychiatric and clinical research across thousands of diverse participant cohorts, translation initiatives, and cross-cultural validation trials.

Construct and Convergent Validity

In the seminal validation investigations by Goodman et al. (1989a, 1989b), the Y-BOCS demonstrated robust convergent validity when compared against existing measures of obsessive-compulsive symptoms. Total Y-BOCS scores exhibited high, statistically significant correlations with the National Institute of Mental Health Global Obsessive Compulsive Scale (NIMH-GOCS; $r = .67$ to $.78$) and the Clinical Global Impression (CGI) of OCD severity ($r = .64$ to $.74$).

Subsequent psychometric investigations have affirmed its convergent properties relative to modern dimensional indices, demonstrating strong correlations with the Obsessive-Compulsive Inventory-Revised (OCI-R; $r = .55$ to $.70$) and the Obsessive-Compulsive subscale of the Comprehensive Psychopathological Rating Scale (CPRS-OCS; $r = .68$ to $.82$). The separate Obsessions and Compulsions subscales demonstrate convergent validity when examined against specific cognitive and behavioral markers, showing differential correlations with cognitive preoccupation measures and behavioral task latencies.

Discriminant (Divergent) Validity

A persistent challenge in psychiatric assessment is distinguishing obsessive-compulsive severity from comorbid depressive and anxiety states. In the initial validation studies, Goodman and colleagues evaluated discriminant validity by administering the Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scale (HAM-A). Although moderate correlations were observed between the Y-BOCS Total Score and HAM-D / HAM-A scores (ranging from $r = .35$ to $.55$), these correlations were markedly lower than the scale’s correlations with other OCD-specific metrics.

Multiple regression and factor-analytic studies have demonstrated that while the “Distress” items (Items 3 and 8) correlate with generalized negative affectivity, the temporal, interference, and control items account for unique, non-overlapping variance specific to obsessive-compulsive psychopathology, confirming its discriminant validity.

Criterion and Predictive Validity

The predictive and treatment-sensitivity characteristics of the Y-BOCS are well documented. Over three decades of randomized, double-blind, placebo-controlled trials of SSRIs (such as fluvoxamine, sertraline, paroxetine, fluoxetine, and citalopram), clomipramine, and specialized cognitive-behavioral protocols have consistently confirmed that the Y-BOCS tracks therapeutic reductions in symptomatology with high fidelity. The scale demonstrates large effect sizes (Cohen’s $d > 1.0$) in active intervention versus placebo comparisons, without floor or ceiling effects within typical clinical cohorts.

Reliability

The reliability of the Y-BOCS has been established across inter-rater, internal consistency, and temporal test-retest dimensions.

Inter-Rater Reliability

Because the Y-BOCS is conducted as a semi-structured interview requiring clinical judgment to probe and synthesize patient reports, inter-rater reliability is a central psychometric requirement. In the original psychometric series by Goodman et al. (1989a), four trained clinician raters simultaneously or sequentially scored 40 OCD patients, yielding extraordinary inter-rater agreement:

• Total Y-BOCS Severity Score: Intraclass correlation coefficient (ICC) = $.98$ ($p < .0001$).
• Obsessions Subtotal: ICC = $.97$.
• Compulsions Subtotal: ICC = $.96$.
• Individual Item Reliability: Pearson correlation coefficients for the individual 10 items ranged from $.86$ to $.98$.

Subsequent multi-site investigations and cross-cultural adaptations (e.g., across German, Japanese, Spanish, Italian, and Turkish versions) have consistently documented inter-rater reliability coefficients exceeding $.85$, provided that raters undergo structured instructional training and calibration exercises.

Internal Consistency

The internal consistency of the core 10-item scale is consistently high across clinical populations. In Goodman’s initial cohort of 80 OCD outpatients, Cronbach’s alpha for the composite 10 items was $.89$, reflecting strong homogeneity among the items while retaining operational breadth. Subscale internal consistencies were recorded at $\alpha = .88$ for the Obsessions Subscale and $\alpha = .89$ for the Compulsions Subscale. Meta-analytic evaluations of the scale’s psychometric properties across international samples report pooled alpha coefficients hovering stably between $.86$ and $.91$.

Test-Retest Temporal Stability

In stable clinical cohorts evaluated over brief retest intervals (ranging from 24 hours to 14 days) prior to initiating active therapeutic protocols, the Y-BOCS exhibits excellent temporal stability. In the original validation study, a subset of patients re-evaluated after an interval without treatment modification showed a test-retest correlation coefficient of $r = .90$ ($p < .001$). Temporal stability coefficients over 1- to 2-week baseline periods across multi-center pharmaceutical trials routinely exceed$r = .80$, confirming that baseline score stability does not exhibit significant clinical drift in the absence of interventions.

Factor Analysis

The latent structural organization of the 10 Y-BOCS items has been evaluated extensively using Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). While the scale was conceptually constructed around two correlated a priori domains—Obsessions (Items 1–5) and Compulsions (Items 6–10)—empirical factor-analytic investigations have revealed a more nuanced latent structure.

The Traditional Two-Factor Model

The initial conceptualization presumed that the 10 items bifurcate along the behavioral-phenomenological fault line dividing obsessions from compulsions:

• Factor 1: Obsession Severity (Items 1, 2, 3, 4, 5)
• Factor 2: Compulsion Severity (Items 6, 7, 8, 9, 10)

While this two-factor model demonstrated acceptable fit in early small-sample analyses and remains the structural foundation for clinical scoring routines, subsequent large-scale structural equation modeling studies revealed that this traditional model often yields poor fit indices (e.g., Comparative Fit Index [CFI] < .90, Root Mean Square Error of Approximation [RMSEA] > .08).

Alternative Factor Solutions: The Resistance/Control Divergence

Extensive psychometric investigations by McKay et al. (2003), Storch et al. (2005), and Amir et al. (1997) demonstrated that the structural variance of the Y-BOCS is better explained by the *type of psychopathological dimension* assessed rather than the pure distinction between obsessions and compulsions. Specifically, the resistance items (Item 4 and Item 9) frequently exhibit problematic psychometric performance, cross-loading weakly or loading onto an isolated factor.

The most widely replicated structural configurations include:

1. The Two-Factor “Symptom Severity” vs. “Resistance/Control” Model

• Core Severity Factor (Distress/Interference/Time): Comprising Items 1, 2, 3, 6, 7, and 8. These items load heavily on a shared latent dimension reflecting the disruptive burden and distress imposed by the pathology. Factor loadings for these core severity items routinely range from $.65$ to $.88$.
• Resistance and Control Factor: Comprising Items 4, 5, 9, and 10 (or in some models, solely Items 4 and 9). This factor reflects the patient’s regulatory coping efforts and perceived agency. Items 4 and 9 often present low or divergent loadings, as high resistance can be found in both highly distressed, newly symptomatic patients and patients demonstrating proactive therapeutic coping.

2. The Three-Factor Model

In structural evaluations encompassing thousands of patients, three distinct latent factors emerge:

• Factor 1: Severity / Core Burden (Time, Interference, Distress across obsessions and compulsions; Items 1, 2, 3, 6, 7, 8).
• Factor 2: Control (Perceived control over obsessions and compulsions; Items 5 and 10).
• Factor 3: Resistance (Active resistance against obsessions and compulsions; Items 4 and 9).

Fit indices for the three-factor model and the modified two-factor model (Severity vs. Resistance/Control) consistently outperform the traditional Obsessions vs. Compulsions model in CFA investigations, showing CFI values exceeding $.95$, Tucker-Lewis Index (TLI) values > $.94$, and RMSEA values < $.05.

Instrument / Measurement Tool

The Yale–Brown Obsessive Compulsive Scale is operationalized as a structured clinical assessment protocol containing specific administrative criteria:

• Instrument Designation: Yale–Brown Obsessive Compulsive Scale (Y-BOCS).
• Format: Clinician-administered semi-structured interview (also available in validated self-report screening adaptations, though the clinician-rated version is the established gold standard).
• Target Population: Adolescents and adults (ages 16–65+); a dedicated child adaptation, the Children’s Yale–Brown Obsessive Compulsive Scale (CY-BOCS), exists for younger populations.
• Prerequisite Procedure: Administration of the comprehensive Y-BOCS Symptom Checklist prior to scoring the severity items, allowing interviewer and patient to identify current and past target symptoms across contamination, aggressive, sexual, religious, symmetry, somatic, and hoarding domains.
• Item Count: 10 primary severity items (Items 1–5: Obsessions Subtotal; Items 6–10: Compulsions Subtotal). An extended 16-item research version includes experimental questions regarding insight, avoidance, indecisiveness, overvalued ideas, and pathological doubt, but these do not contribute to the validated 0–40 severity score.
• Administration Time: Approximately 30 to 45 minutes for the initial full evaluation (inclusive of the symptom checklist); 15 to 20 minutes for longitudinal follow-up tracking evaluations.
• Temporal Frame: Past 7 days (including the day of clinical interview).
• Response Continuum: 5-point clinician rating scale (0 to 4): 0 = None / No symptoms, 1 = Mild, 2 = Moderate, 3 = Severe, 4 = Extreme.
• Scoring Architecture:
  • Obsessions Subtotal: Sum of Items 1, 2, 3, 4, and 5 (Range: 0–20).
  • Compulsions Subtotal: Sum of Items 6, 7, 8, 9, and 10 (Range: 0–20).
  • Total Y-BOCS Severity Score: Sum of Items 1 through 10 (Range: 0–40).
• Standard Clinical Severity Strata:
  • 0 – 7: Subclinical (Non-clinical or fully remitted range)
  • 8 – 15: Mild severity (Mild functional impairment; often responsive to first-line monotherapy)
  • 16 – 23: Moderate severity (Clear disruption of daily living; standard inclusion benchmark for clinical trials)
  • 24 – 31: Severe illness (Marked functional interference, intense distress, pervasive impairment)
  • 32 – 40: Extreme / Incapacitating (Profound functional collapse, constant distress, inability to meet basic self-care needs)

Permissions & Fee and Test Year

The core Yale–Brown Obsessive Compulsive Scale (Y-BOCS) was published in 1989 by Wayne K. Goodman, Lawrence H. Price, Steven A. Rasmussen, and colleagues in the Archives of General Psychiatry. The authors developed the original instrument under academic research protocols supported in part by public funding from the National Institute of Mental Health (NIMH).

Licensing and Accessibility: The original 1989 Y-BOCS severity rating scale and symptom checklist were placed into the public domain by the authors for non-commercial clinical practice, academic instruction, and investigator-initiated scientific research. In these contexts, the instrument may be utilized, reproduced, and translated without financial remuneration or royalty obligations, provided proper attribution and bibliographic citation are maintained.

However, users should be aware that commercial pharmaceutical trials, multi-center industrial studies, and proprietary computerized/digital healthcare software platforms frequently require specialized licensing agreements, certified rater training certifications, or standardized electronic clinical outcome assessment (eCOA) licensing from designated copyright holders and academic repositories. A revised edition, the Yale–Brown Obsessive Compulsive Scale – Second Edition (Y-BOCS-II), was published in 2010 by Goodman, Storch, and colleagues to revise the resistance items and modify scoring conventions; commercial deployment of the Y-BOCS-II may follow distinct licensing provisions.

References

• Amir, N., Foa, E. B., & Coles, M. E. (1997). Factor structure of the Yale-Brown Obsessive Compulsive Scale. Psychological Assessment, 9(1), 44–48. https://doi.org/10.1037/1040-3590.9.1.44
• Foa, E. B., Huppert, J. D., Leiberg, S., Langner, R., Kichic, R., Hajcak, G., & Salkovskis, P. M. (2002). The Obsessive-Compulsive Inventory: Development and validation of a short version. Psychological Assessment, 14(4), 485–496. https://doi.org/10.1037/1040-3590.14.4.485
• Goodman, W. K., Price, L. H., Rasmussen, S. A., Mazure, C., Fleischmann, R. L., Hill, C. L., Heninger, G. R., & Charney, D. S. (1989a). The Yale-Brown Obsessive Compulsive Scale: I. Development, use, and reliability. Archives of General Psychiatry, 46(11), 1006–1011. https://doi.org/10.1001/archpsyc.1989.01810110048007
• Goodman, W. K., Price, L. H., Rasmussen, S. A., Mazure, C., Delgado, P., Heninger, G. R., & Charney, D. S. (1989b). The Yale-Brown Obsessive Compulsive Scale: II. Validity. Archives of General Psychiatry, 46(11), 1012–1016. https://doi.org/10.1001/archpsyc.1989.01810110054008
• McKay, D., Danyko, S. J., Neziroglu, F., & Yaryura-Tobias, J. A. (2003). Factor structure of the Yale-Brown Obsessive-Compulsive Scale: A examination of multidimensionality in a clinical sample. Depression and Anxiety, 17(1), 36–42. https://doi.org/10.1002/da.10081
• Salkovskis, P. M. (1985). Obsessional-compulsive problems: A cognitive-behavioural analysis. Behaviour Research and Therapy, 23(5), 571–583. https://doi.org/10.1016/0005-7967(85)90105-6
• Storch, E. A., Shapira, N. A., Dimaggio, C., Geffken, G. R., Murphy, T. K., & Goodman, W. K. (2005). Reliability and validity of the Yale-Brown Obsessive-Compulsive Scale: Second edition. Journal of Anxiety Disorders, 19(7), 803–814. https://doi.org/10.1016/j.janxdis.2004.09.004
• Woody, S. R., Steketee, G., & Chambless, D. L. (1995). Reliability and validity of the Yale-Brown Obsessive-Compulsive Scale. Behaviour Research and Therapy, 33(5), 597–605. https://doi.org/10.1016/0005-7967(94)00078-P

13. Items of the Scale (Questionnaire)