Second-generation antipsychotics and seizures - a systematic review and meta-analysis of serious adverse events in randomized controlled trials.

Seizures are suspected to be side effects of antipsychotics. To examine a possible causal relationship, we compared the risk of seizures on second-generation antipsychotics to the risk on placebo in randomized controlled clinical trials (RCTs) across diagnostic groups. The primary outcome was any seizure reported as International Conference on Harmonisation-Good Clinical Practice (ICH-GCP)-defined serious adverse event (SAEs). The risk ratio (RR) with antipsychotics versus placebo was synthesized in a pairwise common effects Mantel-Haenszel meta-analysis. For 314 of 597 idenitified placebo-controlled RCTs information about all SAEs could be retrieved from publications, original investigators, pharmaceutical companies and the European Medical Agency. In those, 37 seizures occurred in 42,600 participants on antipsychotics (0.09%) and 28 in 25,042 participants on placebo (0.11%). The meta-analytic results (RR 0,68; 95% Confidence Interval 0.41-1.12) indicated a reduced risk on antipsychotics with a confidence interval including no difference (i.e. RR=1). Neither in sensitivity analyses (excluding events in the safety-follow-up of trials or first-generation antipsychotics; using odds ratios) nor in subgroup analyses (on specific antipsychotics, drug combinations, diagnostic categories, age groups, and study duration) there was evidence for an increased risk on antipsychotics, except for some weak indications of an increased risk on antipsychotics in older and/or demented participants (RRs 1.11 and 1.48, respectively, but with 95% CIs of 0.35-3.49 and 0.41-5.26 including no difference and subgroup tests with p=0.54 and p=0.66 not indicating differences between age groups or diagnostic categories). Consequently, there are no indications that second-generation antipsychotics cause seizures in middle-aged adults and children in most diagnostic groups; rather our results provide some weak evidence for a protective effect. However, there was no data on SAEs available for clozapine, for which observational studies provide the strongest associations with increased seizure rates, and for older and/or demented patients a small additional risk on antipsychotics cannot be excluded.