Background: A sizeable minority of people with schizophrenia do not have complete remission of symptoms. A variety of adjunctive treatments have been used to treat schizophrenia, carbamazepine being one.
Objectives: To review the effects of carbamazepine and its derivatives for the treatment of schizophrenia and schizoaffective psychoses.
Search strategy: Biological Abstracts (1980-1998), The Cochrane Library (Issue 3, 1998), The Cochrane Schizophrenia Group's Register of Trials (August 1998), EMBASE (1980-1998), MEDLINE (1966-1998), PsycLIT (1886-1998) and PSYNDEX (1974-1998) were searched. Citations from included trials were also inspected and relevant companies and authors contacted for additional data.
Selection criteria: All randomised controlled trials comparing carbamazepine, or compounds of the carbamazepine family, to placebo or no intervention, whether as sole treatment or as an adjunct to antipsychotic medication for the treatment of schizophrenia and/or schizoaffective psychoses.
Data collection and analysis: Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were extracted independently by at least two reviewers. Dichotomous data were analysed using Peto odds ratio (OR) and the 95% confidence interval (CI) estimated. Where possible the number needed to treat (NNT) or number needed to harm statistics were calculated.
Main results: There is no clear effect of carbamazepine as the sole maintenance treatment for those with schizophrenia. Eight trials provided very limited data on the value of carbamazepine as an adjunct to antipsychotics. Studies were small and poorly reported. Currently no published data provides convincing evidence that adjunctive carbamazepine has an effect on global functioning, mental state, side effects or acceptability of treatment.
Reviewer's conclusions: Based on currently available randomised trial-derived evidence, carbamazepine cannot be recommend for routine clinical use for treatment or augmentation of antipsychotic treatment of schizophrenia. However, for those with a past history of being responsive to carbamazepine, or for those with associated EEG abnormalities, a trial of the drug may be warranted. More data is expected from trialists and the results of this review may be changed by their inclusion. At present large, simple well designed and reported trials are justified especially if focusing on those with both schizophrenia and EEG abnormalities or violent episodes and people with schizoaffective disorders.