Is it possible for people with severe mental illness to sit less and move more? A systematic review of interventions to increase physical activity or reduce sedentary behaviour.

Individuals with severe mental illness (SMI) (schizophrenia-spectrum, bipolar disorder and major depressive disorder) die 10-20 years prematurely due to physical disorders such as cardiovascular disease. Physical activity (PA) is effective in preventing and managing these conditions in the general population, however individuals with SMI engage in substantially less PA and more sedentary behaviour (SB) compared to healthy counterparts. Furthermore, the effectiveness of intervening to increase PA or reduce SB in SMI populations is unknown. Therefore, we systematically reviewed studies measuring changes in PA or SB following behavioural interventions in people with SMI. A systematic search of major databases was conducted from inception until 1/3/2018 for behavioural interventions reporting changes in PA or SB in people with SMI. From 3018 initial hits, 32 articles were eligible, including 16 controlled trials (CT's; Treatment n = 1025, Control n = 1162) and 16 uncontrolled trials (n = 655). Of 16 CTs, seven (47%) reported significant improvements in PA, although only one found changes with an objective measure. Of 16 uncontrolled trials, 3 (20%) found improvements in PA (one with objective measurement). No intervention study had a primary aim of changing SB, nor did any note changes in SB using an objective measure. In conclusion, there is inconsistent and low quality evidence to show that interventions can be effective in changing PA or SB in this population. Future robust randomized controlled trials, using objectively-measured PA/SB as the primary outcome, are required to determine which behavioural interventions are effective in improving the sedentary lifestyles associated with SMI. Systematic review registration- PROSPERO registration number CRD42017069399.