For patients who fail to report any improvement from SRIs, or cannot tolerate the side effects of an SRI, the next approach is to consider an alternate monotherapy. Inositol, a dietary supplement that is a precursor of the second messenger phosphatidylinositol has demonstrated superiority to placebo in one double-blind study. Clonazepam has demonstrated mixed results, venlafaxine failed to separate from placebo, and trazodone resulted in no difference from placebo. Although not including a placebo, controlled studies of buspirone versus clomipramine and phenelzine versus clomipramine both demonstrated similar efficacy between the two medications.
Although preliminary studies suggest that several other medications may be beneficial for OCD (for example, glutamate-modulating agents), these agents currently lack double-blind, placebo-controlled data to support their efficacy. Given that previous trials of medication were often successful in open-label studies and not in placebo-controlled studies, these medications require more rigorous testing.
The only type of treatment that has been found to be broadly effective for OCD is cognitive behavioral therapy (CBT). The form of CBT that seems to work fairly well for OCD includes exposure and response prevention (ERP): prolonged exposure to obsessional cues and strict prevention of rituals. ERP entails exposure to situations that provoke obsessive anxiety and then abstaining from rituals. Response rates to ERP range from 63% to 90% with an average reduction of 48% of OCD symptoms. Relapse rates after ERP are relatively low but refusal rates are 25% to 30% and drop-out rates are about 28%.
Typically ERP is conducted on a weekly basis, although severity of the disorder may necessitate more frequent sessions. ERP has shown benefit in many different frequency formats and anywhere from 10-16 sessions (usually 90 minute sessions) may be helpful.
Each session begins with a check on homework progress and ends with a new homework/exposure assignment.