BMC Public Health 2009, 9:251 http://www.biomedcentral.com/1471-2458/9/251 identifying short-term beneficial survival strategies and modifying them into long-term beneficial ones; ending with a summary of the session and new home- assignments. Each session is built around a theme. In session 1, trainees get acquainted with each other by telling each other about their symptoms and by setting their personal goals for the training. In session 2, the flight-fight cycle and habits in reaction to symptoms are identified as survival strategies of the body and modified with the learning of the breathing and relax- ation exercise and the reshaping of habits into long-term beneficial ones. In session 3, avoidance and overactivity in reaction to symptoms are identified as survival strategies of the body and modified by scheduling different kinds of activities in a feasible pace alternated with short breaks (5 to 10 min- utes) that is compatible with the trainees' physical condi- tion. In session 4, emotions in reaction to symptoms are iden- tified as useful survival strategies indicating the need for problem-solving. Moreover, the physical symptoms of emotions are notified and reduced or even relieved with the breathing and relaxation exercise. In session 5, thoughts in reaction to symptoms are identi- fied as survival strategies of the mind and, if necessary, modified with the Ellis' ABCDE scheme into more helpful ones. In session 6, a good physical shape is identified as an effective survival strategy of the body, which can be achieved by doing a low cardiac physical activity (like walking or biking) twice a day and increasing this up to a maximum of 60 minutes twice a day, after which physical shape can be maintained by a regular sport twice a week. In session 7, the form at Figure 2 is filled in by the trainees and discussed afterwards with an important and trusted person in his or her own social environment. In sessions 8 to 12, the five steps of the problem-solving method (problem-attitude, problem-definition, alterna- tive solutions, solution plan, solution implementation and evaluation) are identified and practiced. In session 13, a personal First Aid Kit is composed out of the learned long-term beneficial survival strategies aimed to prevent relapse. Control condition: waiting list Patients assigned to the waiting list condition, wait during the group training of 13 weeks, after which they start with their training. Outcome measurements (Cost-)effectiveness is measured with three self-report questionnaires, which are sent to patients' home to be completed before randomization, at the end of the train- ing or waiting list period, after 3 and 12 months after the training (see Figure 1). 1) Short Form Health Survey (SF-36) [23] The SF-36 measures functional health and well-being during the past four weeks with the following eight multi-item scales: Physical functioning, Role function- ing physical, Bodily pain, General health, Vitality, Social functioning, Role functioning emotional and Mental health. The scores of the SF-36 can also be summarized in the Mental and the Physical summary scores [24]. Furthermore, a utility score can be derived from 11 items of the SF-36. These 11 items define six dimensions of health, the SF-6D; Physical function- ing, Role limitations (Role functioning physical in combination with Role functioning emotional), Bod- ily pain, Social functioning, Vitality and Mental health. The outcome of the SF-6D can be converted into Quality Adjusted Life Years (QALYs), the pre- ferred outcome in health economics, using formerly called 'valuations studies' [25]. 2) Symptom Checklist Revised (SCL-90-R) [26] The SCL-90-R measures a broad range of symptoms and their intensity during the past week with the fol- lowing eight multi-item scales: Phobic anxiety, Anxi- ety, Depression, Somatization, Obsessive-compulsive, Interpersonal sensitivity, Hostility and Sleep difficul- ties. The scores of the SCL-90-R can be summarized in the Global severity index, reflecting the overall psy- chological distress. 3) Trimbos/iMTA Questionnaire for Costs associated with Psychiatric Illness (TiC-P) [27] The TiC-P measures direct medical costs due to health- care utilization during the past four weeks, excluding the group training itself. The costs of the training itself are calculated using the records of the institution. The TiC-P also registers the indirect non-medical costs due to productivity loss during the past two weeks. This second part of the questionnaire about indirect costs is based on the short form of the Health and Labour Questionnaire (HLQ). Page 6 of 9 (page number not for citation purposes)