Objectives: Newer atypical antipsychotics have been reported to cause a lower incidence of extrapyramidal side effects (EPS) than conventional agents. This review is to compare antipsychotic-induced EPS relative to placebo in bipolar disorder (BPD) and schizophrenia.
Methods: English-language literature cited in Medline was searched with terms antipsychotics, placebo-controlled trial, and bipolar disorder or schizophrenia and then with antipsychotic (generic/brand name), safety, akathisia, EPS, or anticholinergic use, bipolar mania/depression, BPD, or schizophrenia, and randomized clinical trial. Randomized, double-blind, placebo-controlled, monotherapy studies with comparable doses in both BPD and schizophrenia were included. Absolute risk increase and number needed to treat to harm (NNTH) for akathisia, overall EPS, and anticholinergic use relative to placebo were estimated.
Results: Eleven trials in mania, 4 in bipolar depression, and 8 in schizophrenia were included. Haloperidol significantly increased the risk for akathisia, overall EPS, and anticholinergic use in both mania and schizophrenia, with a larger magnitude in mania, an NNTH for akathisia of 4 versus 7, EPS of 3 versus 5, and anticholinergic use of 2 versus 4, respectively Among atypical antipsychotics, only ziprasidone significantly increased the risk for overall EPS and anticholinergic use in both mania and schizophrenia, again with larger differences in mania, an NNTH for overall EPS of 11 versus 19, and anticholinergic use of 5 versus 9. In addition, risks were significantly increased for overall EPS (NNTH = 5) and anticholinergic use (NNTH = 5) in risperidone-treated mania, akathisia in aripiprazole-treated mania (NNTH = 9) and bipolar depression (NNTH = 5), and overall EPS (NNTH = 19) in quetiapine-treated bipolar depression.
Conclusions: Bipolar patients, especially in depression, were more vulnerable to having acute antipsychotic-induced movement disorders than those with schizophrenia.