Obsessive– Compulsive Disorder 449
80% of the OCD sample reported mental compulsions. Compulsive rituals are usu-
ally performed in order to reduce distress (e.g., repeated handwashing reduces anxiety
evoked by touching an object perceived as possibly contaminated) or to avert some
dreaded outcome (e.g., a person repeatedly checks the stove to ensure the knob is off and
the possibility of fire is prevented). Often compulsions are followed in accordance with
certain rules such as checking seven times that the light switch is turned off before leav-
ing a room. Compulsions perform a neutralization function that is directed at removing,
preventing, or weakening an obsession or its associated distress (Freeston & Ladouceur,
1997a). Even so, compulsions are clearly excessive and often are not even realistically
connected to the situation they are intended to neutralize or prevent (APA, 2000). With
a strong sense of subjective compulsive and unsuccessful attempts to resist the urge,
individuals with OCD usually feel a loss of control over their compulsions. The follow-
ing definition of compulsions is offered:
Clinician Guideline 11.2
Compulsions are repetitive, intentional but stereotypic behaviors or mental responses that
involve a strong subjective urge to perform and a diminished sense of voluntary control that
is intended to neutralize the distress or dreaded outcome that characterizes an obsessional
concern.Diagnostic Criteria
Table 11.1 presents DSM-IV-TR (APA, 2000) diagnostic criteria for OCD. The neces-
sary diagnostic criteria are the presence of obsessions or compulsions that are recog-
nized as excessive or unreasonable at some point during the course of the disorder, and
are time- consuming, cause marked distress, or significantly interfere with functioning.
The impairment criterion is important because many individuals in the general popula-
tion have obsessive or compulsive symptoms. In fact numerous studies have documented
a high frequency of unwanted intrusive thoughts in nonclinical samples that involve
content very similar to clinical obsessions (e.g., Parkinson & Rachman, 1981a; Purdon
& Clark, 1993; Rachman & de Silva, 1978), with ritualistic behavior also reported in
these samples (e.g., Muris, Merckelbach, & Clavan, 1997). Clinical obsessions, however,
are more frequent, distressing, strongly resisted, uncontrollable, time- consuming, and
impairing than their counterpart in the general population (see D. A. Clark, 2004).
When assessing OCD it is also important to distinguish obsessions from other types
of negative cognition. Negative automatic thoughts, worry, and delusions are other types
of cognitive pathology that can be confused with obsessional thinking. To determine if a
recurring distressing cognition should be classified as an obsession, several characteris-
tics should be present such as (1) experienced as recurring, unwanted mental intrusions;
(2) strong efforts to suppress, control, or neutralize the thought; (3) recognition that the
thought is a product of one’s own mind; (4) heightened sense of personal responsibility;
(5) involves ego- dystonic, highly implausible content (i.e., the thought tends to focus on
material that is uncharacteristic of the self); and (6) tends to be associated with neutral-
ization efforts (D. A. Clark, 2004).