Vlasveld 2011.

Methods	Study design: Randomised controlled trial
Participants	Setting: Community Diagnosis: Major depressive disorder assessed using the PHQ‐9.  Workers who reached the cut‐off score of 10 were contacted for the administration of a diagnostic interview. Those who met the Diagnostic and Statistical Manual (DSM‐IV) criteria for major depressive disorder according to the mini ‐ International Neuropsychiatric Interview (MINI) were included. Inclusion criteria: Workers on the sick list for between 4 and 12 weeks who give informed consent Exclusion criteria: Patients who are suicidal, psychotic or with a primary diagnosis of substance abuse or dependence, as assessed by the MINI interview, patients who do not have sufficient command of the Dutch language to fill in the questionnaires, patients who are pregnant, patients with a legal involvement against their employer, e.g. due to a conflict at work Age: Not stated Gender: 54% female Ethnicity: Not stated Country: The Netherlands Sample size (randomised): Total participants 126, intervention 65, control 61
Interventions	Intervention: Collaborative care Contains the four elements of collaborative care: 1) a multi‐professional approach to patient care: Usual occupational physician (PCP), occupational physician (CM), psychiatrist (MH specialist) 2) a structured management plan: Contains the following elements: contracting (patient choice of treatment), adherence enhancing techniques (psychoeducation), manual‐guided self‐help (focuses on behavioural activation, negative thoughts, return to work, and aspects of healthy lifestyle), problem solving therapy (PST), a workplace intervention (CM acts as mediator between patient and employer), active monitoring and, depending on patient preference, prescription of ADs according to a treatment algorithm. Patient starts with PST and the manual guided self‐help, and some patients will also immediately start ADs. The workplace intervention will be fitted in during the first weeks of the intervention. Non‐response will result in adding an extra 6 sessions of PST, or by adding ADs to the treatment plan or by increasing or changing the AD. Continued non‐response at 18 weeks will be referred to specialised mental health care and where medication is prescribed this will be handed over to GP 3) scheduled patient follow‐ups: 9 contacts in 18 weeks (fortnightly). PST = 6 sessions (plus extra 6 when required) 4) enhanced inter‐professional communication: The PCP and CM communicated with each other with written informed consent of the patient. CM consulted MH specialist if needed and received regular group supervision with other CMs Control: Treatment as usual in occupational health
Outcomes	Depression (PHQ‐9): 3, 6, 9, 12 months Medication use: 3, 6, 9, 12 months
Notes	AD: antidepressant; CM: case manager; GP: general practitioner; MH: mental health; PCP: primary care provider; PHQ‐9: Patient Health Questionnaire; PST: problem solving therapy
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated
Allocation concealment (selection bias)	Unclear risk	Insufficient information available to assess
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Short‐term loss to follow‐up based on primary depression outcome (PHQ‐9 response 50% reduction) was: overall 28/126 (22%), 15/65 (23%) intervention and 13/61 (21%) control. Reasons for loss to follow‐up not provided. Intention‐to‐treat analysis reported, multiple imputation used to manage missing data
Selective reporting (reporting bias)	Unclear risk	Insufficient information available to assess
Other bias	Unclear risk	Insufficient information available to assess
Implementation Integrity	Unclear risk	Insufficient information available to assess
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants and personnel could not be blinded, outcome likely to be influenced by lack of blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Assessor was not aware of treatment allocation