Efficacy of behavioural activation in the treatment of negative symptoms in people with schizophrenia spectrum disorders: A systematic review.

Background: Negative symptoms, frequently experienced by people with schizophrenia, can impair functional outcomes and quality of life. Negative symptoms typically affect motivation, communication, and the ability to live independently and are difficult to treat. Several meta-analyses suggest that cognitive behavioural therapy results in a modest reduction in negative symptoms. It is unclear if similar effects can be achieved using behavioural activation. Behavioural activation is a derivative of cognitive behavioural therapy that helps to improve social and emotional functioning by encouraging patients to engage in activities that they value whilst modifying the avoidance responses. Behavioural activation can be a standalone treatment for depressive symptoms that is equally as efficacious as cognitive behavioural therapy. Objective: This systematic review aimed to identify and summarise the evidence about the efficacy of behavioural activation in treating negative symptoms. Design: Systematic review. Setting/Participants: Two published studies conducted in South Korea and the United Kingdom recruited 55 patients. Method: We searched five databases and four trial registries for clinical treatment trials of behavioural activation involving adults diagnosed with negative symptoms of schizophrenia. Studies were screened according to the inclusion criteria and assessed for quality. Results: We identified 5023 published studies. After removing duplicates and conducting screening, two studies were included in this review. One study used a parallel non-randomised trial design whilst the other adopted a single group test-re-test design. Fifty-five participants were recruited from hospital and community settings. Both studies delivered 10 face-to-face sessions of behavioural activation; these were individual in one study and group sessions in the other. One study involved behavioural activation as the treatment whilst the other delivered behavioural activation with motivational interviewing. Neither study reported harms or adverse events. Conclusions: Based on the included studies, there is low-quality evidence that behavioural activation may be helpful in the treatment of negative symptoms. Key limitations of the studies include small sample sizes and overall low study quality. Study registration: The protocol covering this review was registered with Open Science on 18 February 2022 (Registration DOI 10.17605/OSF.IO/57QSW; Weblink: https://osf.io/57qsw). Tweetable abstract: Behavioural activation holds promise in supporting patients experiencing negative symptoms of schizophrenia.