470 TREATMENT OF SPECIFIC ANXIETY DISORDERS
Yale–Brown Obsessive– Compulsive Scale
The Yale–Brown Obsessive– Compulsive Scale (YBOCS) is a 10-item semistructured
interview rating scale that assesses the severity of obsessions and compulsions indepen-
dent of the type (content) or number of symptoms (Goodman et al., 1989a, 1989b). It is
widely used to assess the effectiveness of pharmacological and behavioral treatments for
OCD and has become the “gold standard” for assessment of OC symptom severity in
outcome studies. After indicating his past and current obsessions and compulsions on a
64-item checklist, the patient is questioned by the interviewer on five aspects of symp-
tom expression, using a Likert scale to record the severity of each symptom feature. A
separate obsessions (sum of items 1–5) and compulsions (sum of items 6–10) severity
score is generated based on the same five features of the target symptoms (1) duration/
frequency, (2) interference in social or work functioning, (3) associated distress, (4)
degree of resistance, and (5) perceived uncontrollability of the obsession or compulsion.
A total severity score is most commonly reported by summing over the 10 items.
A number of studies have investigated the psychometric properties of the YBOCS
and various reviews of this literature have been published (see D. A. Clark, 2004; Feske
& Chambless, 2000; Grabill et al., 2008; St. Clare, 2003; Taylor, 1995b, 1998). The
YBOCS Total Score has excellent interrater reliability, good internal consistency, and
temporal reliability. It generally has good convergent validity with other OCD symptom
measures but discriminant validity is lower given its moderate correlation with anxi-
ety and depression measures. Individuals with OCD score significantly higher on the
YBOCS Total Score than nonobsessional patients and nonclinical comparison groups.
A cutoff score of 16 on the YBOCS Total Score yields good sensitivity but low specificity
(Steketee, Frost, & Bogart, 1996; see also Baer, 2000) and posttreatment scores typi-
cally fall by 40–50% in responders (e.g., Abramowitz, Franklin, et al., 2003; Goodman
et al., 1989b). A self- report version of the YBOCS is available that correlates highly with
the interview format, although Grabill et al. (2007) warned that it may overidentify
OCD due to poor specificity (see Baer, 2000, for copy). However, some weaknesses are
apparent such as poor validity for the resistance and control items, lack of factorial sup-
port for separate Obsessions and Compulsions severity subscales, and omission of an
avoidance rating in the standard severity score (Amir, Foa, & Coles, 1997; Deacon &
Abramowitz, 2005; Woody, Steketee, & Chambless, 1995). A copy of the YBOCS has
been reprinted in Antony (2001b).
Clark–Beck Obsessive Compulsive Inventory
The Clark–Beck Obsessive Compulsive Inventory (CBOCI) is a 25-item self- report ques-
tionnaire consisting of 14 items that assess diagnostic and content features of obsessions
and 11 items that assess compulsions (D. A. Clark & Beck, 2002; D. A. Clark, Antony,
Beck, Swinson, & Steer, 2005). It was developed as a screener for OCD with a structure
and response format identical to the BDI-II. The CBOCI items are scored from 0 to 3,
with each item consisting of four response option statements. The measure was designed
to cover the DSM-IV diagnostic criteria for OCD as well as a number of additional
cognitive symptoms. Obsession and Compulsion subscales can be derived as well as a
Total Score.