Obsessive-compulsive disorder (OCD) is a chronic, debilitating neuropsychiatric disorder that affects 1% to 3% of the population worldwide.1,2 Together, serotonin reuptake inhibitors (SRIs) and cognitive-behavior therapy (CBT) are considered the first-line treatment for OCD.3 In children and adults, CBT is considered at least as effective as pharmacotherapy.4 Despite being an effective treatment, CBT continues to have barriers to its widespread use, including limited availability of trained CBT therapists, delayed clinical response, and high costs.5
Only approximately one-half of patients with OCD respond to SRI therapy, and a considerable percentage (30% to 40%) show significant residual symptoms even after multiple trials of SRIs.6-8 In addition, SRIs may have adverse effects (eg, sexual dysfunction, gastrointestinal symptoms) that impair patient adherence to these medications.9 Therefore, finding better treatment options is important for managing patients with OCD.
Augmentation strategies are recommended for patients who show partial response to SRI treatment or poor response to multiple SRIs. Augmentation typically includes incorporating additional medications with the primary drug with the goal of boosting the therapeutic efficacy of the primary drug. Typically, these additional medications have different mechanisms of action. However, there are no large-scale randomized controlled trials (RCTs) to inform treatment augmentation after first-line treatments for OCD produce suboptimal outcomes. The available evidence is predominantly based on small-scale RCTs, open-label trials, and case series.
In this article, we review the evidence for treatment augmentation strategies for OCD and summarize 8 studies that show promising results (Table10-17). We focus only on pharmacologic agents and do not include other biological interventions, such as repetitive transcranial magnetic stimulation over supplementary motor area, ablative neurosurgery, or deep brain stimulation.
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