(Cost-)effectiveness and implementation of a combined lifestyle intervention for outpatients with severe mental illness (GOAL!): a hybrid quasi-experimental study protocol.

Background: People with severe mental illness (SMI) face not only impaired mental health, but also a greater risk of physical comorbidities and a shorter life expectancy compared to the general population. A poor lifestyle plays a substantial role in this disparity. Combined Lifestyle Interventions targeting multiple lifestyle behaviors can improve mental and physical health, and quality of life.