A meta-analytic review of the effectiveness of psychological treatment of functional/dissociative seizures on non-seizure outcomes in adults

Psychological therapies are considered the treatment of choice for functional/dissociative seizures (FDSs). Although most previous studies have focused on seizure persistence or frequency, it has been argued that well-being or health-related quality of life outcomes may actually be more meaningful. This study contributes by summarizing and meta-analyzing non-seizure outcomes to quantify the effectiveness of psychological treatment in this patient group. A pre-registered systematic search identified treatment studies (e.g., cohort studies, controlled trials) in FDSs. Data from these studies were synthesized using multi-variate random-effects meta-analysis. Moderators of treatment effect were examined using treatment characteristics, sample characteristics, and risk of bias. A total of 171 non-seizure outcomes across 32 studies with a pooled sample size of N = 898 yielded a pooled effect-size of d = .51 (moderate effect size). The outcome domain assessed and the type of psychological treatment were significant moderators of reported outcomes. Greater rates of improvement were demonstrated for outcomes assessing general functioning. Behavioral treatments emerged as particularly effective interventions. Psychological interventions are associated with clinical improvements across a broad array of non-seizure outcomes, over and above seizure frequency, in adults with FDSs.