The SMILE Lifestyle Intervention for People with a Severe Mental Illness: Feasibility and (Cost-)Effectiveness

In this thesis, we present a pragmatic RCT evaluating the effectiveness of an intervention (SMILE) targeting lifestyle changes in people with SMI. Alongside, we performed three sub-studies: a process evaluation to gain insight into the feasibility of the intervention in FACT-care practice; a qualitative study on the experiences of people with SMI and their health care professionals with the SMILE intervention; and finally an economic evaluation of the cost-effectiveness of the intervention. We included patients with overweight or obesity, as they were expected to make the greatest health gains from the SMILE intervention. The SMILE intervention is a feasible way to contribute to the physical health through weight loss of people with SMI in a group setting in Dutch ambulatory mental health care. The intervention was well-perceived by both mental health care professionals and clients who participated in the intervention. The intervention was generally well implemented during the trial and showed positive effects for weight change. In addition, the SMILE intervention was found to be cost-effective for weight loss but not for increased QALYs. Physical health and lifestyle behaviours should be integrated into treatments in this population and the SMILE intervention seems to be a promising way to offer clients with SMI support in improving their lifestyle.