Integrated mental health care and vocational rehabilitation intervention to improve return to work rates for people on sick leave due to common mental and functional disorders (IBBIS-II)—a study protocol for a randomized clinical trial

BACKGROUND: Mental illness has an estimated financial burden on the Danish economy of 3.4% of the gross national product every year due to lost productivity, social benefits, and healthcare costs, and approximately 50% of people receiving long-term sickness benefits have a common mental illness. Furthermore, a significant treatment gap exists where less than 30% are treated for their mental illness. The primary objective of the randomized trial is to examine whether people on sick leave with a diagnosis of anxiety, depression, stress, personality disorders, or functional disorders return to work faster and have higher job retention if they receive an integrated and optimized vocational rehabilitation and mental health care intervention, compared to people who receive the standard mental health care and vocational rehabilitation service. METHODS: The trial is designed as an investigator-initiated, randomized, two-group parallel, assessor-blinded, superior trial. A total of 900 participants with a common mental illness will randomly be assigned into two groups: (1) IBBIS-II, consisting of integrated mental health care and vocational rehabilitation, or (2) service as usual (SAU), at two sites in Denmark. The primary outcome is the difference between the two groups in time to return to work (RTW) at 12 months using data from the Danish Register for Evaluation of Marginalization (DREAM) database. DISCUSSION: This study will contribute with new knowledge on vocational recovery and integrated vocational and health care interventions in a Scandinavian context. TRIAL REGISTRATION: ClinicalTrials.govNCT04432129. Registered on June 16, 2020