Study designs of evaluations included in the review
Randomised controlled trials (RCTs) were eligible for inclusion. Crossover studies were excluded.
Specific interventions included in the review
Studies of antipsychotic drugs used in combination with antidepressants were eligible for the review. The antipsychotics used in the included studies were haloperidol, risperidone, olanzapine and quetiapine. Patients in most studies received antidepressants (details reported) for 8 or 12 weeks before randomisation to antipsychotic or placebo. Studies of less than 4 weeks' duration were excluded; the duration of the included studies ranged from 4 to 16 weeks.
Participants included in the review
Participants were patients with OCD non-responsive (normally defined as a <35% or <25% improvement on the Yale-Brown Obsessive Compulsive Scale, Y-BOCS) to previous antidepressant treatment. Studies of patients with co-morbid schizophrenia or other psychotic disorders were excluded. In the included studies, the mean age of the patients ranged from 28 to 44 years and the proportion of men ranged from 25 to 76%.
Outcomes assessed in the review
Studies were required to report on symptoms assessed with the Y-BOCS or clinical response assessed with the Clinical Global Impressions-Improvement Scale (CGI-I).
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.