A Cochrane review [Abstract] 1 included 11 studies with a total of 4144 subjects with anxiety disorders. Three second-generation antipsychotics, olanzapine, quetiapine and risperidone, were studied. Their effects were studied in generalised anxiety disorder (GAD, 9 studies) and in social phobia (2 studies). There were no studies on panic disorder or other primary anxiety disorders.Participants with GAD responded significantly better to quetiapine than to placebo (OR = 2.21, 95% CI 1.10 to 4.45; 4 trials, n= 2262). However, they were more likely to drop out due to adverse events, to gain weight, to suffer from sedation or from extrapyramidal side effects. When quetiapine was compared with antidepressants, there was no significant difference in efficacy-related outcomes, but more participants on quetiapine dropped out due to adverse events, gained weight and felt sedated (2 RCTs, n = 858). Two very small studies (n= 36) examined olanzapine and two trials (n=457) risperidone and found no difference to placebo in response to treatment.
Comment: The quality of the evidence is downgraded by study quality (inadequate allocation concealment, short follow-up time) and potential reporting bias (5 studies published as posters, all trials sponsored by the pharmaceutical company).
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