Second-generation antipsychotics (SGAs) are widely used in treating schizophrenia and related disorders, also other mental disorders. However, the efficacy and safety of SGAs for treating other mental disorders is unclear. A systematic literature search for randomized, placebo-controlled trials of 11 SGAs for treating 18 mental disorders apart from schizophrenia were carried out from database inception to April 3, 2022. The primary outcome was the mean change in the total score for different mental disorders. The secondary outcome was the odds ratio (OR) of response, remission rates and risk ratio (RR) of adverse events (AEs). A total of 181 studies (N = 65,480) were included. All SGAs showed significant effects in treating other mental disorders compared with placebo, except autistic disorder and dementia. Aripiprazole is the most effective treatment for bipolar mania [effect size = -0.90, 95% CI: -1.59, -0.21] and Tourette’s disorder [effect size = -0.80, 95% CI: -1.14, -0.45], olanzapine for bipolar depression [effect size = -0.86, 95% CI: -1.32, -0.39] and post-traumatic stress disorder [effect size = -0.98, 95% CI: -1.55, -0.41], lurasidone for depression [effect size = -0.66, 95% CI: -0.82, -0.50], quetiapine for anxiety [effect size = -1.20, 95% CI: -1.96, -0.43], sleep disorders [effect size = -1.2, 95% CI: -1.97, -0.58], and delirium [effect size = -0.36, 95% CI: -0.70, -0.03], and risperidone for obsessive-compulsive disorder [effect size = -2.37, 95% CI: -3.25, -1.49], respectively. For safety, AE items for each SGAs was different. Interestingly, we found that some AEs of OLZ, QTP, RIS and PALI have significant palliative effects on some symptoms. Significant differences in the efficacy and safety of different SGAs for treatment of other mental disorders should be considered for choosing the drug and for the balance between efficacy and tolerability for the specific patient.Copyright © 2023 Elsevier B.V. All rights reserved.