In- and outpatient lifestyle interventions on diet and exercise and their effect on physical and psychological health: a systematic review and meta-analysis of randomised controlled trials in patients with schizophrenia spectrum disorders and first episode of psychosis

•Non-pharmacological interventions improve many outcomes in non-affective psychosis.•Effect is observed on cognitive, clinical and functional and life-quality outcomes.•Benefit is larger in exercise interventions, especially moderate aerobic exercise.•Effect lasts after follow-up on anthropometric outcomes especially in psychotherapy.•Benefit is observed also specifically in chronic stages of non-affective psychosis.