Antipsychotic combinations in schizophrenia

In the treatment of resistant schizophrenia, a number of meta-analyses attempted to quantify the efficacy and tolerability of antipsychotic (AP) polypharmacy v. monotherapy with contradictory results. Recently, a systematic review and meta-analysis of randomised controlled trials investigated the efficacy and tolerability of AP combination v. monotherapy in schizophrenia. It included 31 studies: 21 double-blind (considered high-quality studies) and 10 open-label (considered low-quality studies). The meta-analysis showed that, overall, the combination of two APs was more effective than monotherapy in terms of symptom reduction (standardised mean difference (SMD) = -0.53, 95% confidence interval (CI) -0.87 to -0.19); however, this result was confirmed only in the subgroup of low-quality studies. Negative symptoms improved when combining a D2 antagonist with a D2 partial agonist (SMD = -0.41, 95% CI -0.79 to -0.03) both in double-blind and open-label studies. In the present commentary, the results of this systematic review are critically discussed in terms of their clinical and research implications.