Are atypical antipsychotic drugs also atypical antidepressants?

To report a case series and review the psychopharmacology of the neuroleptic drugs to suggest that the atypical antipsychotic drugs may have an antidepressant action, at least for those patients with the melancholic subtype.

We note the literature suggesting that the older (or typical) antipsychotic drugs were established as having antidepressant activity, describe an open study of some two dozen patients with a treatment-resistant melancholic depression, describe rapid resolution of depression and augmentation benefits associated with commencing an atypical antipsychotic drug in a percentage of subjects, and then review relevant psychopharmacological studies to consider whether there is a rationale for use of antipsychotic drugs to treat depression.

Of some two dozen patients treated with an atypical antipsychotic drug, almost immediate improvement was noted in four patients, and evidence of augmentation benefit obtained in another three patients.

Impressions from this case series are encouraging. However, as open clinical observational studies are problematic, controlled studies are required to establish whether the atypical antipsychotic drugs have a role in the management of certain expressions of depression, and, in particular, treatment-resistant melancholic depression.