Because only 40 – 60% of all patients with obsessive-compulsive disorder (OCD) respond to selective serotonin reuptake inhibitors (SSRIs), the evaluation of alternative therapy methods in the presence of treatment resistance has high clinical relevance. In this context, many studies have examined additive medication with antipsychotics.

All double-blind randomised controlled trials (DBRCTs) that evaluated the efficacy of a combination therapy of antipsychotics and SSRIs in treatment-resistant OCD were covered by systematic literature searches.

A total of ten DBRCTs were identified (four for quetiapine, three for risperidone, two for olanzapine and one for haloperidol) with a participant collective comprising in total 316 treatment-resistant OCD patients. After the augmentation therapy, significantly more subjects in the intervention group (antipsychotic + SSRI), 32% of the patients, fulfilled the response criterion (reduction in the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) ≥35%) than in the control group (placebo + SSRI) (relative risk (RR)=2.08; 95% CI: 1.3 – 3.32). The standardised mean difference (SMD) of the Y-BOCS reduction between the pooled two study-groups revealed an effect size of 0,62. The sub-group analyses showed significant efficacy only for haloperidol and risperidone. Further significant differences existed regarding the duration of SSRI medication before the augmentation phase.

Based on the favourable benefit-risk-ratio, risperidone can be regarded as the agent of first choice for augmentation treatment with an SSRI. Overall, about one third of patients benefit from this therapy option. However, further scientific studies are needed before sufficiently empirically secured pharmacological treatment recommendations can be expressed.