Obsessive-Compulsive and Related Disorders

Diagnosis

OCD Symptoms Equals Diagnosis?

Most of us, at one time or another, have experienced some or many of the OCD and related symptoms that are described in the Symptoms section. Does this mean that most of us should be diagnosed with OCD? The answer to this is clearly "no." To be considered clinically significant, the obsessions or compulsions must cause significant distress or interfere with the person's social or role functioning and must occupy more than an hour per day. This however is only a general guideline to recognizing the symptoms of OCD, since even those with chronic OCD usually have a waxing and waning course (i.e., OCD symptoms are not evident on a daily basis for a set amount of hours).

Assessment Instruments

The Y-BOCS, a 10-item, clinician-administered scale, has become the most widely used rating scale for OCD. The Y-BOCS is designed to rate symptom severity, not to establish a diagnosis. The clinician should first ask the patient to complete the Y-BOCS symptoms checklist and should review the completed checklist with the patient. This can be a first step in helping patients recognize all the thoughts and behaviors that are part of their illness, and allows the clinician and patient to agree on the symptoms being rated. The checklist can also be used to select target symptoms for treatment.

The Y-BOCS provides five rating dimensions for obsessions and compulsions: time spent or occupied; interference with functioning or relationships; degree of distress; resistance; and control (i.e., success in resistance). The 10 Y-BOCS items are each scored on a four-point scale from 0 = "no symptoms" to 4 = "extreme symptoms." The sum of the first five items is a severity index for obsessions, and the sum of the last five an index for compulsions. A translation of total score into an approximate index of overall severity is:

0-7
subclinical
8-15
mild
16-23
moderate
24-31
severe
32-40
extreme

In our experience, patients experience a 25% decrease in a Y-BOCS score as mild to moderate improvement, and decrease of 35-50% as moderate to marked. In controlled treatment trials, a decrease of greater than or equal to 35% is widely accepted as indicating a clinically meaningful response and translates into a global improvement rating of much or very much improved; many studies, however, have accepted a lower criterion of greater than or equal to a 25% decrease.

Lastly, it is worth noting that in Goodman et al.'s report in 1989, the Y-BOCS' reliability, validity and sensitivity to change are well established. However, extensive reviews of alternative rating scales are available.

Stanford Medicine Resources:

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