Ten studies, of which 7 were uncontrolled case series (n=189) and 3 were placebo controlled double-blind randomised trials (n=105).
Uncontrolled case series: in all studies, CBZ produced a statistically- significant therapeutic effect compared to baseline (range p=0.05 to p=0.0001) and effect sizes ranged from 0.6 to 2.2. Overall, 70% patients experienced at least a marked improvement in symptoms with CBZ. Longer treatment periods (overall range 1 week to 8 years) were significantly associated with better outcomes (r=0.88, p<0.02). The principal side-effects were sedation, rash, ataxia and dizziness, all of which were reported as mild and transient.
RCTs: overall, 71% of patients receiving CBZ experienced substantial improvement compared with 26% of patients receiving placebo. The overall effect size (1.01) showed that CBZ was significantly more effective than placebo at controlling symptoms (p=0.018). Sedation and rash were the most common side-effects, and were mostly transient.