Antipsychotic-induced akathisia is severely distressing. We aimed to investigate relationships between antipsychotic doses and akathisia risk. We searched for randomised controlled trials that investigated monotherapy of 17 antipsychotics in adults with acute schizophrenia until 06 March 2022. The primary outcome was the number of participants with akathisia, which was analysed with odds ratios (ORs). We applied one-stage random-effects dose-response meta-analyses using restricted cubic splines to model the dose-response relationships. We included 98 studies (343 dose arms, 34,225 participants), most of which were short-term and had low-to-moderate risk of bias. We obtained data on all antipsychotics except clozapine and zotepine. In patients with acute exacerbations of chronic schizophrenia, from moderate to high certainty of evidence, our analysis showed that sertindole and quetiapine carried negligible risks for akathisia across examined doses (flat curves), while most of the other antipsychotics had their risks increase initially with increasing doses and then either plateaued (hyperbolic curves) or continued to rise (monotonic curves), with maximum ORs ranging from 1.76 with 95% Confidence Intervals [1.24, 2.52] for risperidone at 5.4 mg/day to OR 11.92 [5.18, 27.43] for lurasidone at 240 mg/day. We found limited or no data on akathisia risk in patients with predominant negative symptoms, first-episode schizophrenia, or elderly patients. In conclusion, liability of akathisia varies between antipsychotics and is dose-related. The dose-response curves for akathisia in most antipsychotics are either monotonic or hyperbolic, indicating that higher doses carry a greater or equal risk compared to lower doses.
Keywords: Dose-effect; Dosing; Extrapyramidal symptoms; Movement disorders; Randomised controlled trials; Side effects.
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