Psychiatric comorbidities complicate the treatment of obsessive-compulsive disorder (OCD) and are much more the rule than the exception in clinical practice (Table 1).1-6 Even so, surprisingly few studies have examined comorbidities’ effects on OCD treatment, and results have been mixed.
For the typical patient with obsessive-compulsive symptoms, we discuss our experience and evidence that supports:
- clinically useful tools to differentiate OCD from other obsessive and anxiety disorders
- how to address comorbidities that pose acute danger or would prevent effective psychotherapy
- how to modify first-line OCD treatments—cognitive behavioral therapy (CBT) and serotonin reuptake inhibitors (SRIs)7-9—to also manage most comorbid disorders.
Table 1
Common psychiatric comorbidities with OCD
| Comorbidities | Estimated prevalence in OCD patients |
|---|---|
| Personality disorders | 63% |
| Major depressive disorder | 28 to 31% |
| Simple phobia | 7 to 48% |
| Social phobia | 11 to 16% |
| Bipolar disorder | 15% |
| Eating disorders | 8 to 13% |
| Alcohol abuse | 8% |
| Panic disorder | 6 to 12% |
| Tourette’s syndrome or tic disorders | 6 to 7% |
| Source: Data from references 1-6 | |
IS OCD PRIMARY?
OCD-like obsessive thoughts or repetitive behaviors may be evident in a number of psychiatric disorders. Distinguishing OCD from masquerading or co-occurring conditions is important because interventions can differ.
Patients with generalized anxiety disorder (GAD), for example, may experience ruminative, anxious thoughts that mimic obsessions. Somatoform conditions such as hypochondriasis or body dysmorphic disorder are characterized by intense preoccupation with illness or appearance, respectively. Repetitive or compulsive behaviors may be seen in impulse control or developmental disorders such as pathologic gambling, trichotillomania, and Asperger’s disorder.
To help differentiate OCD from these conditions, consider the function of a patient’s symptoms. In OCD, obsessions are experienced as ego-dystonic and generally cause great anxiety. OCD patients perform compulsive rituals to alleviate anxiety but do not gain pleasure from their actions. Contrast this with trichotillomania’s repetitive behavior—commonly experienced as pleasurable or gratifying—or with GAD’s ruminative thoughts—seen as ego-syntonic worries about real-life situations.
ASSESSING OCD, COMORBID CONDITIONS
When you suspect psychiatric comorbidity with OCD, an accurate and thorough assessment is key to successful treatment (Table 2).10-14
In specialty OCD clinics, the Structured Clinical Interview for DSM-IV (SCID-IV)15 or Anxiety Disorders Interview Schedule for the DSM-IV (ADIS-IV)10 are routinely given to assess the most common comorbid conditions. In clinical practice, however, these instruments can take up to several hours to perform, especially for patients who meet criteria for several disorders.
An alternative may be the Mini International Neuropsychiatric Interview (MINI).11 The MINI is a short, structured, diagnostic interview for DSM-IV and ICD-10 that takes about 15 minutes and screens for most conditions commonly comorbid with OCD. The MINI provides less-detailed information than the SCID-IV or the ADIS-IV but allows for a quick, accurate diagnosis while using a structured format.
Table 2
Common assessment tools for patients with suspected OCD
| Structured clinical interviews | Time to administer | Use |
|---|---|---|
| Anxiety Disorders Interview Schedule-IV (ADIS-IV) | 2+ hrs | Detailed assessment of anxiety disorders |
| Mini-International Neuropsychiatric Interview (MINI) | 15 to 30 min | Brief screen for diagnosis |
| OCD-specific measures | ||
| Yale-Brown Obsessive Compulsive Scale (YBOCS) | 30 min | Severity and OCD symptom types |
| Obsessive Compulsive Inventory-Revised (OCI-R) | 5 to 10 min | Self-report severity of OCD symptoms |
| Source: Data from references 10-14 | ||
The Yale-Brown Obsessive Compulsive Scale (YBOCS) is widely used.12,13 It includes a checklist of common obsessions and compulsions plus 10 items measuring interference with daily living, distress, resistance, control, and time spent on symptoms. Each item is scored from 0 to 4, for a total score of 0 to 40.
The YBOCS has good reliability and validity, is available in both clinician-rated and self-rated versions, and can be given repeatedly to measure treatment progress. A Children’s Yale-Brown Obsessive-Compulsive Scale (CYBOCS) is useful for patients ages 6 to 17.16
TREATING UNCOMPLICATED OCD
CBT. When OCD is not concurrent with another diagnosis, expert consensus guidelines recommend CBT as first-line treatment.17 Most patients treated with exposure and response prevention (ERP) therapy—the specialized CBT for reducing anxiety that triggers obsessive-compulsive symptoms—report reduced symptoms and often maintain those gains over time.18
In specialty clinics, patients frequently engage in intensive ERP (2 hours per day, 3 to 5 times per week for about 3 weeks). Although studies find excellent outcomes with intensive OCD treatment,18 it is not always practical or indicated (as in patients with moderate symptoms). Less-intensive protocols, such as biweekly sessions, have also shown promise in studies examining how session frequency affects treatment outcome.19
Many studies supporting ERP’s efficacy in OCD have included relatively homogenous samples under well-controlled conditions. Some investigations have also found good effects for ERP when including patients with complex treatment histories, concomitant pharmacotherapy, and comorbid conditions.20
Medication. Functional imaging studies suggest that OCD results from dysregulation in the socalled “OCD circuit”—the orbitofrontal cortex, anterior cingulate, and caudate nucleus. In patients with OCD, metabolic activity in this region is increased at rest relative to controls, increases further with symptoms, and decreases after successful treatment.21 The serotonin hypothesis—which emerged from observation that OCD symptoms responded to serotonergic medications but not to noradrenergic ones—suggests serotonin system dysregulation in patients with OCD.