The impact of gender on treatment effectiveness of body psychotherapy for negative symptoms of schizophrenia: A secondary analysis of the NESS trial data.

Despite promising findings from small-scale studies suggesting that body psychotherapy may be an effective treatment for negative symptoms, these results were not replicated in a recent multisite trial. In this trial a far smaller proportion of women were recruited relative to earlier studies, which may be an issue given the gender mix of the sample evaluated has been found to affect trial outcomes in schizophrenia. Using data from our multisite trial, the interaction between gender and treatment allocation as a predictor of outcomes was examined in 275 participants (72 women and 203 men) randomised to either a body psychotherapy or Pilates group. Negative symptoms were found to significantly reduce in women randomised to the body psychotherapy condition in comparison to Pilates, while no such effect was detected in men. Consistent with the smaller trials, this improvement was found to relate predominantly to expressive deficits. These findings suggest that body psychotherapy may be an effective treatment for negative symptoms in women. These findings emphasise the importance of sample characteristics in determining trial outcome in psychological treatment studies.