Fig. 1

Study procedure. Patients who score above the cut-off score for any type of sleep disorder on the Holland Sleep disorders Questionnaire (HSDQ+) will be invited for extensive diagnostic evaluation, followed by patient-targeted sleep treatment. Those participants will be randomly divided in one of two conditions: in TAU+SI-T0 sleep diagnosis and sleep intervention (SI) will start immediately (T0), in addition to the treatment as usual (TAU). In TAU+SI-T1 sleep diagnosis and SI will start after 6 months (T1). Questionnaires will be filled in at T0, T1 and T2 (after 12 months), measuring sleep, general functioning, specific mental disorder symptoms, and quality of life. For patients scoring below the cut-off score for a sleep disorder (HSDQ-), participation is limited to filling out the questionnaires at T0