Aims. The aim of this study was to explore distinct trajectories of caregivers' depressive symptoms and the effects of a training programme on these trajectories over 18 months after the programme. Background. Overall effects of caregiver-training programmes on family caregivers' depressive symptoms have been reported, but few studies explored distinct courses of changes in caregivers' depressive symptoms and followed up intervention effects on these distinct courses. Design. Randomized clinical trial. Methods. Family caregivers (n = 116) were randomly assigned into experimental (n = 57) and control (n = 59) groups. The experimental group received the training programme with telephone consultation and the control group received written educational materials and social telephone follow-ups. Caregivers' depressive symptoms were assessed from June 2009 - March 2012 by selfcompleted questionnaires before, at 2 weeks and 3, 6, 12 and 18 months after the intervention. Groups of individual trajectories were distinguished using groupbased trajectory modelling. Results. Caregivers' depressive symptoms fell into three stable trajectories: nondepressed, mildly blue and depressed. After controlling for covariates, caregivers who received the caregiver-training programme were less likely than those who did not experience persistent depressive symptoms (b = -1.92, odds ratio = 0.15, P < 0.05). Conclusion. Depressive symptoms of family caregivers of persons with dementia were relatively stable and followed three distinct courses: non-depressed, mildly blue and depressed. Therefore, caregivers' depressive symptoms should be assessed as early as possible. Caregivers in the experimental group had a lower probability of persistent depressive symptoms than caregivers in the control group. Therefore, this training programme can be used by healthcare providers for persons with dementia and their caregivers. Trial registration number: NCT02667951. References