More evidence on additive antipsychotic effect of adjunctive mirtazapine in schizophrenia: an extension phase of a randomized

Department of Mental Health and Alcohol Research, National Institute for Health and Welfare, Helsinki, FinlandObjective Adjunctive mirtazapine improved negative symptoms of schizophrenia in several studies. Recently, we found an improvementalso in positive symptoms when mirtazapine was added to first generation antipsychotics (FGAs) in a 6 week randomized controlled trial(RCT). The short duration of that trial was its limitation. This study aimed to explore whether longer treatment is worthwhile.Method Completers of the RCT (n¼39) received open-label add-on mirtazapine for additional 6 weeks. The Positive and NegativeSyndrome Scale (PANSS) total score (primary outcome) and several other clinical parameters were measured prospectively.Results During the open-label phase, significant improvement was achieved in all parameters, with an effect size of 0.94 (CI 95%¼0.45–1.43) on the primary outcome and an impressive additive antipsychotic effect. Patients who received mirtazapine during both phasesdemonstratedgreaterimprovementinpositivesymptoms(29.6%versus21.2%,p¼0.027)thanthosewhoreceivedmirtazapineduringopen-label extension phase only.Conclusions These findings support our previous data on the additive antipsychotic effect of mirtazapine in FGAs-treated schizophrenia.Mirtazapinemaybeeffectiveinothersymptomdomains,too.Longerdurationofmirtazapinetreatmentmayyieldadditionalbenefits.Iftheseresults will be confirmed inlargerstudies, add-on mirtazapine may become a feasible option indifficult-to-treatschizophrenia. Copyright #2010 John Wiley & Sons, Ltd.key words—schizophrenia; antidepressants; mirtazapine; antipsychotics