Sandra Schwarz

Head-to-head comparisons of metabolic side effects of second generation antipsychotics in the treatment of schizophrenia: a systematic review and meta-analysis

OBJECTIVE The metabolic side effects of second-generation antipsychotics (SGA) are serious and have not been compared head to head in a meta-analysis. We conducted a meta-analysis of studies comparing the metabolic side effects of the following SGAs head-to-head: amisulpride, aripiprazole, clozapine, olanzapine, quetiapine, risperidone, sertindole, ziprasidone, zotepine. METHOD We searched the register of the Cochrane schizophrenia group (last search May 2007), supplemented by MEDLINE and EMBASE (last search January 2009) for randomized, blinded studies comparing the above mentioned SGA in the treatment of schizophrenia or related disorders. At least three reviewers extracted the data independently. The primary outcome was weight change. We also assessed changes of cholesterol and glucose. The results were combined in a meta-analysis. RESULTS We included 48 studies with 105 relevant arms. Olanzapine produced more weight gain than all other second-generation antipsychotics except for clozapine where no difference was found. Clozapine produced more weight gain than risperidone, risperidone more than amisulpride, and sertindole more than risperidone. Olanzapine produced more cholesterol increase than aripiprazole, risperidone and ziprasidone. (No differences with amisulpride, clozapine and quetiapine were found). Quetiapine produced more cholesterol increase than risperidone and ziprasidone. Olanzapine produced more increase in glucose than amisulpride, aripiprazole, quetiapine, risperidone and ziprasidone; no difference was found with clozapine. CONCLUSIONS Some SGAs lead to substantially more metabolic side effects than other SGAs. When choosing an SGA for an individual patient these side effects with their potential cause of secondary diseases must be weighed against efficacy and characteristics of the individual patient.

A Meta-Analysis of Head-to-Head Comparisons of Second-Generation Antipsychotics in the Treatment of Schizophrenia

OBJECTIVE Whether there are differences in efficacy among second-generation antipsychotics in the treatment of schizophrenia is a matter of heated debate. The authors conducted a systematic review and meta-analysis of blinded studies comparing second-generation antipsychotics head-to-head. METHOD Searches of the Cochrane Schizophrenia Groups register (May 2007) and MEDLINE (September 2007) were conducted for randomized, blinded studies comparing two or more of nine second-generation antipsychotics in the treatment of schizophrenia. All data were extracted by at least three reviewers independently. The primary outcome measure was change in total score on the Positive and Negative Syndrome Scale; secondary outcome measures were positive and negative symptom subscores and rate of dropout due to inefficacy. The results were combined in a meta-analysis. Various sensitivity analyses and metaregressions were used to examine bias. RESULTS The analysis included 78 studies with 167 relevant arms and 13,558 participants. Olanzapine proved superior to aripiprazole, quetiapine, risperidone, and ziprasidone. Risperidone was more efficacious than quetiapine and ziprasidone. Clozapine proved superior to zotepine and, in doses >400 mg/day, to risperidone. These differences were due to improvement in positive symptoms rather than negative symptoms. The results were rather robust with regard to the effects of industry sponsorship, study quality, dosages, and trial duration. CONCLUSIONS The findings suggest that some second-generation antipsychotics may be somewhat more efficacious than others, but the limitations of meta-analysis must be considered. In tailoring drug treatment to the individual patient, small efficacy superiorities must be weighed against large differences in side effects and cost.

Increased Event-Related Potentials and Alpha-, Beta-, and Gamma-Activity Associated with Intentional Actions

Objective: Internally guided actions are defined as being purposeful, self-generated and offering choices between alternatives. Intentional actions are essential to reach individual goals. In previous empirical studies, internally guided actions were predominantly related to functional responses in frontal and parietal areas. The aim of the present study was to distinguish event-related potentials and oscillatory responses of intentional actions and externally guided actions. In addition, we compared neurobiological findings of the decision which action to perform with those referring to the decision whether or not to perform an action. Methods: Twenty-eight subjects participated in adapted go/nogo paradigms, including a voluntary selection condition allowing participants to (1) freely decide whether to press the response button or (2) to decide whether they wanted to press the response button with the right index finger or the left index finger. Results: The reaction times were increased when participants freely decided whether and how they wanted to respond compared to the go condition. Intentional processes were associated with a fronto-centrally located N2 and P3 potential. N2 and P3 amplitudes were increased during intentional actions compared to instructed responses (go). In addition, increased activity in the alpha-, beta- and gamma-frequency range was shown during voluntary behavior rather than during externally guided responses. Conclusion: These results may indicate that an additional cognitive process is needed for intentional actions compared to instructed behavior. However, the neural responses were comparatively independent of the kind of decision that was made (1) decision which action to perform; (2) decision whether or not to perform an action). Significance: The study demonstrates the importance of fronto-central alpha-, beta-, and gamma oscillations for voluntary behavior.