Do all obsessive-compulsive disorder subtypes respond to medication?

Obsessive-compulsive disorder (OCD) in children is strikingly similar in clinical presentation and treatment responsiveness to OCD in adults. While treatment is commonly effective for OCD not all subtypes of OCD are similarly responsive to treatment. Numerous studies describe the differential responsiveness of OCD subtypes to pharmacological treatment in adults, yet few such studies exist in pediatric OCD. This manuscript reviews the extant literature that addresses differential response of OCD subtypes to medication intervention. Specific OCD subtypes can be derived utilizing the following strategies: symptom factor analysis, comorbidity latent class analysis, concurrent internalizing disorders, concurrent externalizing disorders, tic-related subtype and early-onset subtype are reviewed in relation to data on differential pharmacotherapy response. Only externalizing disorders moderate treatment response in pediatric OCD. Specifically, attention-deficit hyperactivity disorder, oppositional defiant disorder and conduct disorder are associated with poorer response to medication treatment. Hoarding appears to be associated with a poor response to medication in adults, but data are sparse in children. The presence of tic disorders may also predict poorer response to pharmacotherapy in pediatric OCD. Strategies for treatment of the tic-related subtype of OCD, while strongly supporting the use of antipsychotic-augmentation for enhanced response in adults, are lacking controlled data in pediatric OCD.