29,30 In addition, there is evidence for the efficacy of venlafaxine in treatment-resistant OCD.31 The SRIs (including all the SSRIs and the SNRTs clomipramine and venlafaxine) are generally used in higher doses for OCD than for depression and may require an extended period of time, 8 to 12 weeks or longer, before they ameliorate symptoms to a clinically significant degree. Two reasonably

large studies report rates of response to SRI treatment for SRI naivc patients; these Inhibitors,research,lifescience,medical rates were about 53%32 and 42 %.33 From 60% to 80% of patients with OCD respond to multiple trials of SRIs,34-38 with most studies reporting nonresponder rates closer to 60%. No SRI has been proven more this website effective than others in head-to-head comparisons, so the selection of an SRI for individual patients with OCD can be made on the basis of side effects and half-life. The efficacy seems to be maintained over time with continuing SRI treatment,28,39,40 but since OCD symptoms generally worsen during stress, some fluctuations in symptom severity while taking Inhibitors,research,lifescience,medical medication are not unusual; symptoms recur when Inhibitors,research,lifescience,medical treatment is ended.28,39-41 Unfortunately, even with a typical 30% to 60% decrease in their OCD symptom severity,42 many patients are left with significant symptoms. Because of this, other pharmacological strategies have been used. Most commonly, neuroleptics or agents with serotonergic properties

are used to augment SRI treatment. Of the neuroleptics, only risperidone has been established in controlled trials as an effective augmentation of SRIs in treatment-resistant OCD.43,44 Additionally, several open-label Inhibitors,research,lifescience,medical trials have found olanzapine an effective augmentation of SRIs in OCD.45-49 Subgroups of OCD patients may be particularly helped by neuroleptic augmentation; most definitively, patients with OCD and comorbid tics

have responded well to this strategy,17 which supports the position that the dopaminergic system plays a role in some subtypes of OCD. Haloperidol was found to be an effective augmentation to fluvoxamine in a placebo-controlled Inhibitors,research,lifescience,medical trial in patients with comorbid OCD and tics, but not in those with OCD alone.50 Similarly, there is some evidence that patients with schizotypal personality disorder may do better with neuroleptic augmentation. An open-label trial of pimozide was effective in treating the OCD symptoms in patients with either also comorbid tics or schizotypal personality.51 Among the serotonergic agents reported in the literature as useful augmentations to SRIs in OCD are buspirone, lithium, trazodone, clonazepam, and clomipramine (augmenting an SSRI). Buspirone and lithium were reported to be helpful in OCD on the basis of open-label trials and case series, but controlled trials have produced disappointing results21,52 There has been no controlled trial of trazodone augmentation.