Integrated Mental Healthcare and Vocational Rehabilitation for People on Sick Leave with Anxiety or Depression: 24-Month Follow-up of the Randomized IBBIS Trial

Integration of vocational rehabilitation and mental healthcare has shown some effect on work participation at 1-year follow-up after sick leave with depression and anxiety. We aimed to study the effect on work and health outcomes at 2-year follow-up, why we performed a randomized trial was conducted to study the effectiveness of integrated intervention (INT) compared to service as usual (SAU) and best practice mental healthcare (MHC). We included 631 participants, and at 24-month follow-up, we detected no differences in effect between INT and SAU. Compared to MHC, INT showed faster return-to-work (RTW) rates (p = 0.044) and a higher number of weeks in work (p = 0.024). No symptom differences were observed between the groups at 24 months. In conclusion, compared to SAU, INT was associated with a slightly higher work rate reaching borderline statistical significance at 12-month follow-up and lower stress levels at 6-month follow-up. The disappearance of relative effect between 12 and 24 months may be explained by the fact that the intervention lasted less than 12 months or by delayed spontaneous remission in the SAU group after 12 months. Despite the lack of effect at long-term follow-up, INT still performed slightly better than SAU overall. Moderate implementation difficulties, may partly explain the absence of the hypothesized effect. Integrated intervention, as implemented in this trial, showed some positive effects on mid-term vocational status and short-term stress symptom levels. However, these effects were not sustained beyond the duration of the intervention.