Do antipsychotic augmentation work in SSRI resistant OCD? Int Jl Neuro Psy.April.2013

25.04.2013

SSRIs are the drugs of first choice in OCD.Soomro et al’s 2008 Cochrane review did not find any difference in efficacy between different SSRIs.Half of OCD patients do not respond to initial SSRI trial.Change to another SSRI is the recommended strategy.Tricyclics and antipsychotic augmentation strategies are third line of treatment.Antipsychotics are suggested based on hyper dopaminergic state in OCD.

Markus Dold, Martin Aigner, Rupert Lanzenberger and Siegfried Kasper  from Vienna report the results of the metaanalysis of all double blind placebo controlled RCTs in which adult OCD patients received SSRI plus antipsychotics compared against SSRI plus placebo.Primary outcome measures were 1.Change in mean YBCOS score 2. the  response rate. Decrease in YBOCS score of 35% or more was defined as response.

From the initially identified 1494 abstracts, 12 studies were identified that meet all inclusion criteria having a total of 294 patients.Five studies examined  augmentation with Quetiapine , three with Risperidone , two with Olanzapine  and one each with Aripiprazole  and Haloperidol each.

Results

28% of patients in augmentation group reached response criteria compared with 13% in placebo group. Pooled relative risk was 2.10 ( ie significant effect) and NNT was 6.

Subgroup analysis showed that only Risperidone had significantly higher effect size than placebo when both response rate ( dichotomous data) and changes in YBCOS total score (continuous )were both considered.Other antipsychotics did not show more efficacy than placebo on response rates. Total score changes showed Aripiprazole and  Haloperidol also as effective.

Only risperidone showed significant efficacy in both the outcome measures.( ie relative risk based on response rates and standardised mean difference based on total score changes). Though Aripiprazole and Haloperidol were effective in total score changes , this was based on only one trial.

Conclusions: This analysis suggest Risperidone as the preferred agent for augmentation of SSRI in OCD.

Limitations: Small number of participants.Large variation between studies in terms of participant inclusion criteria.

Haloperidol and Risperidone are more potent D2 blockers than other antipsychotics tested.D2 receptor involvement is likely in OCD.

Numbers:

Relative Risk: Numerical values >1 indicate a larger response to antipsychotic augmentation than to placebo medication. If the reported 95% CI do not include the value of 1, a statistically significant effect can be assumed.

Continuous data (YBOCS changes) were analysed using standardized mean differences (SMDs) with the associated 95% CI. Numerical values >0 indicate a positive (beneficial) effect of the adjunctive antipsychotic.

Summary of the article:

Antipsychotic augmentation of serotonin reuptake inhibitors in treatment-resistant obsessive-compulsive disorder: a meta-analysis of double-blind, randomized, placebo-controlled trials. Dold M, Aigner M, Lanzenberger R, Kasper S. Int J Neuropsychopharmacol. 2013 Apr;16(3):557-74

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