Multicentre randomised controlled trial of the Norwegian health in work service for patients with common mental disorders or musculoskeletal disorders: the Norwegian Sickness Absence Clinic (NSAC) Efficacy Study

Introduction In many countries, a high or increasing rate of sickness absence is challenging the sustainability of present sickness absence benefit schemes. Most sickness absence is certified on the grounds of common mental disorders or musculoskeletal disorders, and substantial effort has been invested in developing interventions promoting return to work for these patients.

In Norway, the Health in Work ((HelseIArbeid), HIA) clinics were established as outpatients' services within the specialised healthcare system, with the aim of improving health and supporting return to work. The HIA service admits patients with low-to-moderate anxiety/depression and/or musculoskeletal disorders.

In this protocol, we describe the naturalistic multicentre randomised controlled trial Norwegian Sickness Absence Clinic Efficacy study, which aims to determine the effect of HIA on work participation and health. Methods and analyses The HIA outpatient service is staffed by clinical psychologists, physiotherapists, medical specialists in physical medicine and rehabilitation and employment support supervisors from the Norwegian Labour and Welfare Administration.

Patients admitted to HIA have access to multidisciplinary assessment and treatment. The trial recruits' patients from five HIA outpatient clinics in Northern Norway.