OBJECTIVE
To meta-analyze the efficacy and tolerability of topiramate-antipsychotic cotreatment in schizophrenia.
DATA SOURCES
PubMed/MEDLINE database were searched until September 5, 2015, using the keywords topiramate AND antipsych* OR neurolept* OR specific antipsychotic names.
STUDY SELECTION
Randomized controlled trials (RCTs) of topiramate-antipsychotic cotreatment versus placebo and ongoing antipsychotic treatment in patients with schizophrenia spectrum disorders were included.
DATA EXTRACTION
Two evaluators extracted data. Standardized mean difference (SMD), weighted mean difference (WMD), and risk ratio (RR) ± 95% CIs were calculated.
RESULTS
In 8 RCTs, lasting a mean ± SD of 13.6 ± 4.9 weeks, 439 patients were randomized to topiramate (100-400 mg/d) versus placebo (trials = 7) or ongoing antipsychotic treatment (trial = 1). Topiramate outperformed the comparator regarding total psychopathology (trials = 6, n = 269, SMD = -0.57 [95% CI, -1.01 to -0.14], P = .01), positive symptoms (trials = 4, n = 190, SMD = -0.56 [95% CI, -1.0 to -0.11], P = .01), negative symptoms (trials = 4, n = 190, SMD = -0.62 [95% CI, -1.13 to -0.10], P = .02) general psychopathology (trials = 3, n = 179, SMD = -0.69 [95% CI, -1.27 to -0.11], P = .02), body weight (trials = 7, n = 327, WMD = -3.14 kg [95% CI, -5.55 to -0.73], P = .01), and body mass index (BMI) (trials = 4, n = 198, WMD = -1.80 [95% CI, -2.77 to -0.84], P = .0003). Topiramate's efficacy for total psychopathology and weight reduction effects were not mediated/moderated by trial duration, topiramate dose, sex, age, inpatient status, baseline Positive and Negative Syndrome Scale, or baseline BMI. Conversely, clozapine-topiramate cotreatment moderated greater efficacy, but less weight loss, compared to topiramate-nonclozapine antipsychotic combinations. All-cause discontinuation was similar between topiramate and control groups (trials = 7, RR = 1.24 [95% CI, 0.76 to 2.02], P = .39). Topiramate trended only toward more paresthesia than placebo (trials = 4, RR = 2.03 [95 % CI, 0.99 to 4.18], P = .05).
CONCLUSIONS
Topiramate-antipsychotic cotreatment significantly reduced total, positive, negative, and general psychopathology and weight/BMI in patients with schizophrenia spectrum disorder while being well tolerated. However, larger studies are needed to confirm and extend these findings.