Yale – Brown Obsessive Compulsive Scale (Y-BOCS)

1. Abstract

The Yale–Brown Obsessive Compulsive Scale (Y-BOCS) is universally acknowledged as the gold standard clinician-administered psychometric instrument for assessing the clinical severity and treatment response of obsessive-compulsive disorder (OCD). Originally developed by Wayne K. Goodman and colleagues in 1989, the instrument was specifically designed to decouple the assessment of symptom severity from the heterogeneous phenomenological content of obsessions and compulsions. The standard Y-BOCS consists of two primary operational components: the comprehensive Y-BOCS Symptom Checklist, which surveys past and current manifestations across dozens of idiosyncratic symptom presentations, and the core 10-item Y-BOCS Severity Scale. The severity scale comprises two structurally parallel five-item subscales: the Obsessions Subscale (Items 1 to 5) and the Compulsions Subscale (Items 6 to 10).

Each item evaluates a specific dimensional operationalization of symptom severity over the preceding seven-day interval, including: time spent/frequency, degree of interference with occupational and psychosocial functioning, subjective psychological distress, degree of active resistance exerted against symptoms, and the patient’s perceived degree of control over intrusions and repetitive rituals. Items are rated on an anchored 5-point ordinal Likert scale spanning from 0 (none/no symptoms) to 4 (extreme/incapacitating), yielding subscale totals ranging from 0 to 20 and a global composite severity score ranging from 0 to 40. Extensively documented psychometric properties across four decades of empirical investigation demonstrate excellent internal consistency (Cronbach’s alpha typically ranging between 0.86 and 0.93 for the total score), exceptional inter-rater reliability (intraclass correlation coefficients and Pearson r values exceeding 0.90 to 0.98), robust test-retest stability, and remarkable sensitivity to treatment-induced change across pharmacological trials (e.g., selective serotonin reuptake inhibitors) and behavioral interventions such as Exposure and Response Prevention (ERP).

2. Keywords

Yale-Brown Obsessive Compulsive Scale, Y-BOCS, obsessive-compulsive disorder, psychometrics, symptom severity, clinician-administered rating scale, exposure and response prevention, treatment response criteria, construct validity, obsessions and compulsions

3. Authors

The Yale–Brown Obsessive Compulsive Scale was conceived, standardized, and validated by a multidisciplinary team of psychiatric researchers and clinical psychologists affiliated with Yale University School of Medicine (New Haven, Connecticut) and Brown University (Providence, Rhode Island):

• Wayne K. Goodman, M.D. — Principal architect; Professor and D.C. and Irene Ellwood Chair in Psychiatry at Baylor College of Medicine (previously affiliated with Yale University and Mount Sinai School of Medicine).
• Lawrence H. Price, M.D. — Professor of Psychiatry and Human Behavior at the Warren Alpert Medical School of Brown University; Director of Research at Butler Hospital.
• Steven A. Rasmussen, M.D. — Chair of the Department of Psychiatry and Human Behavior at the Warren Alpert Medical School of Brown University.
• Chawki Mazure, Ph.D. — Norma Weinberg Spungen and Joan Rhodes Spungen Professor of Psychiatry and Psychology, Yale School of Medicine.
• Robert L. Delgado, M.D. — Department of Psychiatry, Yale University School of Medicine.
• G. R. Heninger, M.D. — Professor Emeritus of Psychiatry, Yale School of Medicine.
• Dennis S. Charney, M.D. — Anne and Joel Ehrenkranz Dean of the Icahn School of Medicine at Mount Sinai (formerly at Yale University).

4. Purpose

The primary diagnostic and clinical objective of the Y-BOCS is to provide an objective, standardized, and highly granular quantitative measure of current symptom severity in individuals already diagnosed with obsessive-compulsive disorder. Crucially, the authors explicitly delineated that the Y-BOCS is not an epidemiological screening tool or a categorical diagnostic interview; it is not intended to differentiate OCD from other Axis I/DSM-5 psychiatric conditions, nor should it be utilized in isolation to establish a baseline clinical diagnosis. Rather, its clinical and empirical utility resides in tracking dimensional disease burden and evaluating clinical response trajectories in pharmacological and psychotherapeutic intervention protocols.

Prior to the introduction of the Y-BOCS in 1989, clinical trials in OCD were severely constrained by the lack of psychometrically robust, uniform assessment batteries. Earlier instruments—such as the Leyton Obsessional Inventory (LOI), the Maudsley Obsessive Compulsive Inventory (MOCI), and general psychiatric global impressions scales—suffered from profound methodological limitations. Most notably, earlier inventories conflated the specific phenomenological topography of a patient’s symptoms (e.g., whether the individual exhibited washing rituals versus checking compulsions) with the severity of the underlying neurobehavioral illness. A patient with ten distinct minor checking rituals might artificially score higher than an individual with a single, completely incapacitating contamination obsession that consumes twelve hours per day. The Y-BOCS resolved this fundamental psychometric conundrum by bifurcating the assessment paradigm: the symptom checklist comprehensively establishes the presence of diverse thematic manifestations, while the core severity scale measures the global impact of whatever symptoms are currently active on five distinct neurofunctional parameters.

In contemporary clinical psychiatry and cognitive-behavioral research, the Y-BOCS serves multiple critical functions:

• Standardized Treatment Response Classification: In academic clinical trials, a decrease of ≥25% or ≥35% on the total Y-BOCS score, frequently combined with a Clinical Global Impressions–Improvement (CGI-I) rating of “much improved” or “very much improved,” is the universally accepted benchmark defining therapeutic response. Remission is rigorously defined across psychiatric consensus literature as achieving a post-treatment Y-BOCS score ≤12 (or in stringent trials, ≤8).
• Longitudinal Symptom Tracking: In outpatient and inpatient clinical settings, routine administration allows psychotherapists executing Exposure and Response Prevention (ERP) to monitor the attenuation of distress and the restoration of behavioral flexibility over time.
• Stratification of Illness Severity: Total scores correspond to internationally recognized severity strata: 0–7 indicates subclinical symptoms; 8–15 denotes mild OCD; 16–23 indicates moderate OCD; 24–31 reflects severe OCD; and 32–40 represents extreme, profoundly incapacitating illness.
• Neurobiological and Neuroimaging Correlates: The Y-BOCS provides an essential dimensional metric utilized in functional neuroimaging (fMRI, PET) to correlate cortico-striato-thalamo-cortical (CSTC) circuit dysfunction with quantitative symptom burden before and after deep brain stimulation (DBS), transcranial magnetic stimulation (TMS), or surgical capsulotomy.

5. Psychological Construct

The Yale-Brown Obsessive Compulsive Scale measures the psychological construct of Obsessive-Compulsive Symptom Severity, conceptualized as a multi-dimensional clinical syndrome characterized by recurrent, intrusive cognitive phenomena (obsessions) and purposeful, repetitive behavioral or mental actions executed according to rigid rules (compulsions). Rather than rating severity based on the bizarre or idiosyncratic nature of the thoughts, the construct captures the formal neurofunctional disruption across two primary structural domains: Obsession Severity and Compulsion Severity.

Domain 1: Obsessive Intrusions (Items 1–5)

Obsessions are defined within the psychometric architecture of the scale as intrusive, unwanted thoughts, images, urges, or doubts that spontaneously violate the individual’s stream of consciousness, causing pronounced psychological distress, anxiety, or guilt. The construct assesses five functional parameters:

• Time Occupied (Item 1): The chronological duration and frequency of obsessive intrusions throughout an average waking day over the past week, ranging from zero hours, through brief transient intrusions (<1 hour), to pervasive, continuous intrusions occupying more than 8 hours daily.
• Functional Interference (Item 2): The degree to which intrusive cognitions disrupt psychosocial functioning, occupational performance, academic execution, and interpersonal relationships. This reflects cognitive efficiency impairment, task incompletion, and executive disruption.
• Subjective Distress (Item 3): The affective toll directly generated by the intrusions, operationalized as acute panic, generalized dread, existential disgust, or overwhelming inner turmoil.
• Active Resistance (Item 4): The intentional mental or behavioral exertion deployed by the individual to disregard, suppress, challenge, or deflect the intrusive ideation. Paradoxically, highly severe or chronic patients may show low resistance due to clinical demoralization, cognitive exhaustion, or complete surrender to the illness.
• Perceived Control (Item 5): The subjective efficacy of the individual’s cognitive control mechanisms. This reflects cognitive flexibility and the capacity to divert attentional allocation away from the intrusion once it emerges.

Domain 2: Compulsive Behaviors (Items 6–10)

Compulsions are conceptualized as repetitive, stereotyped behavioral acts (e.g., hand washing, checking locks, ordering items) or covert mental rituals (e.g., silent counting, silent prayer, internal neutralization of “bad” words) that the patient feels subjectively compelled to perform in response to an obsession or according to idiosyncratic, rigid rules. The construct evaluates identical severity vectors:

• Time Consumed (Item 6): The total aggregate time devoted to completing physical rituals or mental neutralizing routines daily, indexing mechanical disability.
• Functional Interference (Item 7): The pragmatic vocational and interpersonal impairment directly caused by enacting rituals (e.g., occupational tardiness caused by multi-hour checking routines, cutaneous skin erosion from compulsive scouring).
• Anticipatory/Prevented Distress (Item 8): The magnitude of visceral affective arousal, panic, or autonomic distress that immediately erupts if the individual is artificially blocked or prevented from completing the compulsive ritual to subjective completion.
• Active Resistance (Item 9): The degree of conscious willpower mobilized to arrest, delay, or withhold the compulsive ritual when urged to execute it.
• Perceived Control (Item 10): The respondent’s lived experience of behavioral self-agency and ability to terminate rituals once initiated, capturing compulsive drive automaticity.

6. Theoretical Framework

The structural formulation of the Y-BOCS is anchored at the convergence of cognitive-behavioral models of OCD and modern neuropsychiatric paradigms. Historically, the instrument emerged during a paradigm shift in psychiatry, characterized by the publication of the DSM-III and DSM-III-R, which moved clinical diagnostic taxonomy toward operationalized criteria with high inter-rater reliability.

Cognitive-Behavioral Framework

From a behavioral standpoint, the Y-BOCS operationalizes the principles established by O. Hobart Mowrer’s two-factor theory of avoidance learning as modified by Paul Salkovskis, Stanley Rachman, and David M. Clark. In this framework, obsessions represent conditioned stimuli that evoke unconditioned or conditioned emotional responses (anxiety/distress). Compulsions represent maladaptive instrumental behaviors that are strongly reinforced via negative reinforcement—the temporary reduction or termination of distress following the execution of the neutralizing act.

The scale directly targets these theoretical parameters: Item 3 and Item 8 quantify the emotional conditioning (distress evoked by obsession and distress when compulsions are blocked), while Items 4, 5, 9, and 10 assess the regulatory and inhibitory processes governing avoidance habits. Salkovskis’ cognitive formulation posits that intrusive cognitions are ubiquitous across non-clinical populations; what distinguishes clinical OCD is the catastrophic appraisal of intrusions as carrying personal responsibility for harm. The Y-BOCS assesses the downstream clinical consequences of these catastrophic appraisals—prolonged mental occupation, functional paralysis, and frantic neutralizing behavior.

Neuropsychiatric and Frontostriatal Circuitry Framework

The Y-BOCS was developed by clinical neuroscientists who viewed OCD as a biological neuropsychiatric disorder characterized by abnormalities within the cortico-striato-thalamo-cortical (CSTC) loops, specifically involving the orbitofrontal cortex (OFC), anterior cingulate cortex (ACC), and the striatum (caudate nucleus). In this neurobiological model, the “resistance” and “control” items (Items 4, 5, 9, 10) directly evaluate frontally mediated executive control, top-down cognitive inhibition, and motor behavioral gating.

The perceived loss of control mirrors the persistent, hyperactive error-detection signals originating in the anterior cingulate cortex (the subjective feeling that “something is wrong” or incomplete) that fail to be suppressed by striatal inhibitory gating mechanisms. By providing an unconfounded metric of severity separate from symptom content, the Y-BOCS enabled investigators to demonstrate that CSTC hypermetabolism normalizes following both successful pharmacotherapy (SSRIs) and successful behavioral neuroadaptation via ERP.

7. Validity

The psychometric validity of the Y-BOCS has been examined across hundreds of international empirical investigations across diverse cultural, linguistic, and clinical cohorts.

Construct and Convergent Validity

In their seminal validation studies, Goodman et al. (1989a, 1989b) established strong convergent validity by comparing the Y-BOCS Severity Scale with established global clinical measures. The Y-BOCS demonstrated robust, statistically significant correlations with the Clinical Global Impressions–Severity (CGI-S) scale (r = 0.65 to 0.74, p < 0.001) and the Global Obsessive-Compulsive Scale (r = 0.67 to 0.78). Furthermore, convergent correlations with self-report measures of OCD, such as the Maudsley Obsessive Compulsive Inventory (MOCI) and the Obsessive-Compulsive Inventory–Revised (OCI-R), consistently range between r = 0.52 and 0.70.

Discriminant / Divergent Validity

A crucial psychometric attribute of the Y-BOCS is its capacity to evaluate obsessive-compulsive pathology independently of general affective comorbidities. Studies assessing discriminant validity reveal moderate correlations with measures of general depressive symptoms (e.g., Hamilton Depression Rating Scale [HAM-D], r = 0.35–0.42; Beck Depression Inventory [BDI], r = 0.38–0.45) and generalized anxiety (Hamilton Anxiety Rating Scale [HAM-A], r = 0.36–0.48). Importantly, these coefficients are significantly lower than those observed between the Y-BOCS and other OCD-specific severity indices, proving that the instrument captures a distinct psychopathological construct rather than general negative affectivity or neurotic distress.

Predictive and Evaluative Validity (Sensitivity to Change)

The Y-BOCS exhibits unmatched sensitivity to therapeutic change. Multicenter double-blind placebo-controlled clinical trials of clomipramine, fluvoxamine, sertraline, paroxetine, and fluoxetine have repeatedly demonstrated that the Y-BOCS detects differential treatment divergence within 2 to 6 weeks of protocol initiation (effect sizes typically ranging from Cohen’s d = 0.80 to 1.40). The instrument also reflects significant decreases in total scores corresponding to successful exposure and response prevention therapy, with treatment effect sizes frequently exceeding d = 1.50 in intensive clinical trials.

8. Reliability

The reliability of the Y-BOCS has been confirmed across diverse clinical trials, demonstrating its psychometric stability across evaluators and temporal testing intervals.

Internal Consistency

The internal consistency of the 10-item Y-BOCS Severity Scale is consistently high. In the original validation cohort reported by Goodman et al. (1989a), Cronbach’s alpha was 0.89 for the total score. Subsequent multinational validation investigations have reported alpha coefficients ranging from 0.86 to 0.93 for the total severity scale. When examined at the subscale level, the Obsessions Subscale typically demonstrates a Cronbach’s alpha between 0.77 and 0.88, while the Compulsions Subscale yields alphas between 0.82 and 0.91, confirming strong item coherence.

Inter-Rater Reliability

Because the Y-BOCS is designed as a semi-structured clinician-rated interview, establishing inter-examiner consistency is paramount. Goodman et al. (1989a) reported excellent inter-rater reliability among trained clinical raters across 40 patients, with Pearson correlation coefficients (r) exceeding 0.95 for the total score (individual item intraclass correlation coefficients [ICCs] ranged from 0.80 to 0.99). Independent reliability trials conducted across the United States, Europe, and Asia have consistently reaffirmed ICCs between 0.88 and 0.98, demonstrating that rater training protocols provide reliable scoring.

Test-Retest Stability

In stable clinical samples re-evaluated over intervals of 7 to 14 days without active psychotherapeutic or pharmacological intervention, the test-retest reliability coefficient of the total Y-BOCS score ranges from r = 0.81 to 0.90 (Goodman et al., 1989b; Woody et al., 1995). Subscale test-retest correlations remain equally robust, typically registering above 0.80, confirming that the scale is not confounded by random daily symptom fluctuations.

9. Factor Analysis

Although the Y-BOCS was originally conceptualized as an instrument consisting of two theoretically distinct subscales—Obsessions (Items 1–5) and Compulsions (Items 6–10)—extensive empirical factor analyses have revealed a more complex structural profile.

Empirical Factor Structures

Numerous exploratory factor analyses (EFA) and confirmatory factor analyses (CFA) conducted over the past three decades have evaluated the dimensional structure of the 10 severity items. The primary factor solutions documented in the psychometric literature include:

• The Classical Two-Factor Model (Obsessions vs. Compulsions): Corresponds directly to Goodman et al.’s original structural division. However, multiple CFA studies (e.g., Amir et al., 1997; McKay et al., 2003) have demonstrated that the traditional two-factor model provides suboptimal model fit (e.g., Comparative Fit Index [CFI] < 0.90, Root Mean Square Error of Approximation [RMSEA] > 0.08) because items evaluating resistance and control correlate poorly with items measuring time, interference, and distress within the same domain.
• The Alternative Three-Factor Model: Extensively validated by McKay et al. (2003), Moritz et al. (2002), and Storch et al. (2005), this model divides the 10 items into: (1) Core Severity / Symptom Disturbance (Items 1, 2, 3, 6, 7, 8—capturing time, interference, and distress across both obsessions and compulsions); (2) Obsession Resistance/Control (Items 4 and 5); and (3) Compulsion Resistance/Control (Items 9 and 10). This model exhibits superior fit indices across clinical samples (CFI > 0.95, TLI > 0.94, RMSEA ≈ 0.05).
• The Two-Factor Structural Alternative (Severity vs. Resistance/Control): Confirmatory studies by Kim et al. (1994) identified a two-factor structure based not on symptom phenomenology (obsessions vs. compulsions), but on process: Factor 1 captures Symptom Burden (Items 1, 2, 3, 6, 7, 8; factor loadings ranging from 0.65 to 0.88), while Factor 2 captures Effort/Cognitive Resistance and Control (Items 4, 5, 9, 10; factor loadings ranging from 0.55 to 0.82).

The Resistance Paradox

A recurring psychometric finding in factor-analytic investigations involves the performance of Item 4 (Resistance to Obsessions) and Item 9 (Resistance to Compulsions). In severely chronic OCD, active resistance often drops significantly because patients have become completely exhausted or have accommodated to their illness. Consequently, a decrease in resistance can paradoxically yield a “higher” (worse) score on the Likert anchor, even though a lack of resistance in milder patients may signify a lack of distress. Statistical analyses demonstrate that eliminating Item 4 or modifying the resistance scoring algorithm frequently enhances model fit and total scale unidimensionality.

10. Instrument / Measurement Tool

The structural, administrative, and evaluative characteristics of the clinical Y-BOCS interview are detailed below:

• Instrument Type: Semi-structured, clinician-administered diagnostic rating interview (self-report versions exist but the clinician-rated version remains the gold standard).
• Target Population: Adults diagnosed with Obsessive-Compulsive Disorder (a downward extension, the Children’s Yale-Brown Obsessive Compulsive Scale or CY-BOCS, is utilized for pediatric populations aged 6–17).
• Item Count: 10 core severity items (Items 1–5 for Obsessions, Items 6–10 for Compulsions), preceded by a comprehensive multi-category Symptom Checklist containing over 50 specific obsessional and compulsive targets.
• Response Scale: 5-point anchored Likert scale, ranging from 0 to 4:
  • 0: None / No symptoms / Complete control / Always resists
  • 1: Mild / Less than 1 hour daily / Slight interference / Little distress / Much control / Much resistance
  • 2: Moderate / 1 to 3 hours daily / Definite but manageable interference / Moderate distress / Moderate control / Some resistance
  • 3: Severe / 3 to 8 hours daily / Substantial impairment / Severe distress / Little control / Often yields
  • 4: Extreme / Greater than 8 hours daily / Incapacitating impairment / Near-constant disabling distress / Completely yields / No control
• Standard Administration Protocol:
  • The clinician first administers the Y-BOCS Symptom Checklist to identify current and historical symptoms across major categories (Contamination, Aggression, Symmetry, Sexual, Somatic, Hoarding, Washing, Checking, Repeating, Ordering, Counting, etc.).
  • The clinician and patient establish the target obsessions and compulsions that have been most prominent over the preceding 7 days.
  • The clinician conducts the semi-structured interview covering Items 1 through 10, probing the patient for concrete examples of time consumed, functional disruption, affective distress, active resistance, and executive control.
  • Administration time ranges between 30 and 45 minutes for a baseline interview, and 15 to 20 minutes for follow-up evaluation sessions.
• Scoring and Clinical Interpretation:
  • Obsessions Subscale Score: Sum of Items 1 to 5 (Range: 0–20).
  • Compulsions Subscale Score: Sum of Items 6 to 10 (Range: 0–20).
  • Total Y-BOCS Severity Score: Sum of all 10 items (Range: 0–40).
  • Clinical Severity Cut-Off Strata:
    • 0–7: Subclinical OCD
    • 8–15: Mild OCD
    • 16–23: Moderate OCD
    • 24–31: Severe OCD
    • 32–40: Extreme / Incapacitating OCD

11. Permissions & Fee and Test Year

The Yale–Brown Obsessive Compulsive Scale was formally developed and published in 1989 by Wayne K. Goodman and colleagues at Yale University School of Medicine. The original 10-item clinician-rated instrument and the associated Symptom Checklist were placed in the public domain for research and clinical use to facilitate scientific investigation into obsessive-compulsive disorder. Consequently, no licensing fees or royalties are required to utilize the original 1989 Y-BOCS for non-commercial clinical practice, academic research, or non-funded biomedical trials.

Commercial clinical trials, digital healthcare applications, and proprietary corporate implementations should request explicit permission or determine institutional licensing compliance through Wayne K. Goodman, M.D., or the respective institutional technology licensing offices of Yale University and Brown University. In 2010, the Yale-Brown Obsessive Compulsive Scale – Second Edition (Y-BOCS-II) was published to address specific psychometric limitations of the original scale (modifying the resistance item, revising anchors, and expanding the total score to 50); researchers utilizing the Y-BOCS-II should reference the updated copyright and administration parameters associated with that revision.

12. 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

Goodman, W. K., Price, L. H., Rasmussen, S. A., Mazure, C., Delgado, P., 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., Fleischmann, R. L., Hill, C. L., 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

Kim, S. W., Dysken, M. W., & Kuskowski, M. (1994). The Yale-Brown Obsessive-Compulsive Scale: A reliability and validity study. Psychiatry Research, 51(2), 207–216. https://doi.org/10.1016/0165-1781(94)90040-x

McKay, D., Danyko, S. J., Neziroglu, F., & Yaryura-Tobias, J. A. (2003). Factor structure of the Yale-Brown Obsessive-Compulsive Scale: A critical review and reexamination. Depression and Anxiety, 17(3), 107–114. https://doi.org/10.1002/da.10079

Moritz, S., Meier, B., Kloss, M., Jacobsen, D., Wein, C., Fricke, S., & Hand, I. (2002). Dimensional structure of the Yale-Brown Obsessive-Compulsive Scale. Psychiatry Research, 109(2), 193–199. https://doi.org/10.1016/s0165-1781(02)00007-9

Rosario-Campos, M. C., Miguel, E. C., Quarantini, L., Sato, P., Iwasaki, F., Runha, V., Prado, H., Mathis, M. A., Torres, A. R., Fontenelle, L. F., Ferrão, Y. A., & Shavitt, R. G. (2006). The Dimensional Yale-Brown Obsessive-Compulsive Scale (DY-BOCS): An instrument for assessing obsessive-compulsive symptom dimensions. Molecular Psychiatry, 11(5), 495–504. https://doi.org/10.1038/sj.mp.4001798

Storch, E. A., Shapira, N. A., Dimaggio, C., Geffken, G. R., Murphy, T. K., & Goodman, W. K. (2005). The two-factor structure of the Yale-Brown Obsessive-Compulsive Scale: Evidence from a nonclinical sample. Journal of Anxiety Disorders, 19(6), 707–718. https://doi.org/10.1016/j.janxdis.2004.07.001

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)00091-c

13. Items of the Scale (Questionnaire)