Objective To identify factors predicting the long term course of complicated grief, depression, and suicide ideation in a community based sample of relatives bereaved through suicide. Design Longitudinal cohort study. Included in the multilevel regression models were sociodemographic and personality features, mental health history, records of received help, long term complicated grief, depression, and suicide ideation. Setting Community based sample located in the northern part of the Netherlands. Participants 153 first degree relatives and spouses of 74 people who had committed suicide. Main outcome measures Complicated grief, depression, and suicide ideation assessed at 2.5 months, 13 months and 96-120 months (8-10 years) by means of self report questionnaires. Results Complicated grief, depression, and suicide ideation were mutually associated in relatives and spouses of people who had committed suicide. A history of attempted suicide was associated with long term suicide ideation (odds ratio 5.5, 95% confidence interval 1.8 to 16.7; P=0.003). Depression was more likely to be predicted by female sex and low mastery, whereas complicated grief was more likely to be predicted by the trauma of losing a child. The risk of both complicated grief and depression decreased over time; for complicated grief the change corresponded with a Cohen's d effect size of 0.36 at 13 months and 0.89 at 96-120 months; for depression these figures were 0.28 at 13 months and 0.94 at 96-120 months. The long term course of bereavement was not affected by family based cognitive behavioural therapy, support from a general practitioner, and/or mental healthcare. Mutual support was associated with an increased risk of complicated grief: B regression coefficient=6.4 (95% confidence interval 1.8 to 11.0; P=0.006). Throughout this long term study, selection bias might have affected some outcomes. Conclusion In relatives bereaved by suicide, suicide ideation is associated with an increased risk of long term complicated grief and depression. The risk of complicated grief and depression decreases over time. Although mutual support is associated with an increased risk of complicated grief, we could not draw conclusions about a causal relation.