Adjunctive minocycline for schizophrenia: A meta-analysis of randomized controlled trials

This study aimed to conduct a meta-analysis of the efficacy and safety of adjunctive minocycline for schizophrenia. Randomized controlled trials (RCTs) comparing adjunctive minocycline with placebo in patients with schizophrenia were included in the meta-analysis. Two independent investigators extracted and synthesized data. Standard mean differences (SMDs), risk ratio (RR) ±95% confidence intervals (CIs) and the number-needed-to-harm (NNH) were calculated. Eight RCTs with 548 schizophrenia patient including 286 (52.2%) patients on minocycline (171.9±31.2 mg/day) and 262 (47.8%) on placebo completed 18.5±13.4 weeks of treatment. Meta-analyses of Positive and Negative Syndrome Scale (PANSS) (7 RCTs with 8 treatment arms)/Brief Psychiatric Rating Scale (BPRS) (1 RCT) total score [SMD: −0.64, (95%CI: −1.02, −0.27), P=0.0008; I2=74%], positive, negative and general symptom scores [SMD: −0.69 to −0.22 (95%CI: −0.98, −0.03), P=0.02-0.00001; I2=7-63%] revealed a significant superiority of adjunctive minocycline treatment over the placebo. There was no significant difference regarding neurocognitive function, discontinuation rate and adverse drug reactions between the two groups. This meta-analysis showed that adjunctive minocycline appears to be efficacious and safe for schizophrenia. Due to significant heterogeneity, future studies with a large sample size are needed to confirm these findings.