BMC Public Health 2009, 9:140 http://www.biomedcentral.com/1471-2458/9/140 the allocation of every OP and saved the randomization file. If an OP in the control group dropped out within a month of randomization, we reused the attributed number of randomization. If an OP in the experimental group dropped out before being trained in the RTW-E pro- gramme, we reused the attributed number of randomiza- tion, as we wanted to prevent skewness in the distribution between the experimental and control groups as much as possible. Recruitment of occupational physicians Participating OPs were recruited from May 2006 until August 2006 from various occupational health services geographically widespread over the Netherlands. The OPs were invited by a written letter accompanied by an infor- mation brochure in which the purpose, the demands, and the gains of the study were explained. After inclusion, the control group was offered a one-day training in the RTW- E programme if they had included the requested eight patients. For attending the training and each tutorial ses- sion, OPs received educational credits recognized by the National Association of Occupational Medicine. Before randomization, the OPs were committed to presenting eight patients for inclusion by signing an agreement. In addition, every OP received a seven-item questionnaire concerning personal (one item) and professional charac- teristics (seven items). We also committed the manage- ment of the occupational health services of participating OPs to the study by requesting them to sign an agreement in which they confirmed the feasibility of the study. Recruitment of patients Inclusion criteria We included patients absent from work due to CMDs if they were on sick leave for at least two weeks and no longer than eight weeks at the moment of inclusion. CMDs were defined as stress-related, adjustment, anxiety, or depressive disorders. Stress-related disorders were clas- sified according to the guidelines for OPs [34,35]. Anxiety, depressive, and adjustment disorders were classified by the Diagnostic Statistical Manual (DSM), version IV. We included only patients who, at the moment of inclusion, had not yet fully returned to work. Exclusion criteria Patients with a current psychiatric disorder at the moment of inclusion, such as PTSS, substance-related disorder, or psychotic disorder as defined by DSM IV classification, were excluded. Also, patients with a primary somatic dis- order according to the OP were excluded. Furthermore, non-Dutch speaking patients were excluded. Procedure Patients who met the inclusion criteria according to the OP were invited to participate in the study. After a verbal invitation by the OP, patients received a written informa- tion leaflet about the study. The leaflet described the pur- pose and demands of the study, and contained an informed consent form. With the permission of the patient, the OP sent his name and telephone number to researcher EN, who contacted every patient by telephone to ask if they needed more information to decide whether or not to participate in the study. If the patients decided to participate, they were requested to sign a written informed consent form, for participating in a telephone diagnostic interview of 25 minutes with researcher EN, to fill in a baseline questionnaire and 4 fol- low-up questionnaires at 3, 6, 9, and 12 months after reporting sick leave, respectively. Furthermore, patients gave informed consent to register daily, on weekly regis- tration forms, their hours spent working, on sick leave, or on vacation, until they returned fully to work. After informed consent, researcher EN conducted a telephone diagnostic interview as soon as possible in order to check eligibility for inclusion in the study. Researcher EN informed the OPs about the inclusion or exclusion of a patient by sending them an email. If, during the diagnos- tic interview, patients were found to be suffering from a 'depressive episode', the risk of suicide was assessed using a protocol. In the case that we found a moderate or high suicidal risk, EN informed the patient and recommended the patient to inform their practitioner(s) about this. If the patient had not informed their practitioner(s) as we appointed, we informed the practitioner about the risk by ourselves if the severity of suicidal risk was deemed to be more important than the informed consent requirement. After inclusion, the OPs in the intervention group coun- selled their patients according to the RTW-E programme and the OPs in the control group counselled their patients according to the CAU. After the OPs in the intervention group finished their counselling, they sent a copy of the filled-in homework assignment forms to researcher EN. These forms were used as indicators of compliance with the RTW-E programme. Intervention Training OPs in the intervention group The OPs in the intervention group received a two-day training in order to apply the RTW-E programme. Thereaf- ter, three follow-up tutorial sessions were planned during the inclusion period. During these sessions, difficulties with applying the RTW-E programme were discussed with other participating OPs and practical solutions were exchanged for problems that had arisen. These sessions were guided by researchers EN or JvdK, or by an external well-informed psychologist. Treatment of patients in the intervention group After two or three weeks of sick leave, patients were informed about the RTW-E programme by their OP. Apart Page 5 of 11 (page number not for citation purposes)