Adjunctive antidepressant drug therapies in the treatment of negative symptoms of schizophrenia

The negative symptoms of schizophrenia comprise one of several identified symptom clusters associated with the disorder. Although consensus on the precise components of the negative syndrome and on definitions for specific negative symptoms have not been reached, Cor the purpose of this review, negative symptoms include blunted affect, poverty of thought content and speech, apathy, social withdrawal and anergia. Negative symptoms are among the most disabling and treatment-resistant symptoms of schizophrenia, and various approaches to treatment have been taken, including augmentation of conventional antipsychotic treatment with antidepressants. Assessment of the effect of treatments an negative symptoms can be problematic and, therefore, clinical trials need to be of adequate duration and systematic attempts need to be made to rule out secondary causes of negative symptoms that may mimic or exacerbate them. Placebo-controlled studies of fluoxetine and fluvoxamine, which controlled for secondary negative symptoms, have demonstrated substantial improvement in negative symptoms compared with placebo. Significant exacerbation in psychotic symptoms was not reported in these controlled trials. This, therefore, represents a promising clinical option for treating negative symptoms. It appears that the maximum benefit of antidepressant augmentation may not be achieved until at least 12 weeks after initiation of therapy. Therefore, trials of shorter duration may understate the potential efficacy of this combination.