Evaluation of a guided internet-based self-help intervention for older adults after spousal bereavement or separation/divorce: A randomised controlled trial

•The guided internet intervention was efficacious compared to a wait-list group.•It improved grief, depression, psychopathology, embitterment, and loneliness.•Widowed and divorced participants benefitted both from the intervention.•It was also efficacious for participants with milder grief symptoms at baseline.•Gains were maintained over three months. While several internet interventions target severe prolonged grief symptoms after bereavement, no randomised controlled trial investigated interventions for prolonged grief after separation/divorce. This randomised controlled trial aimed to evaluate the efficacy of a guided internet-based self-help intervention for prolonged grief symptoms after spousal bereavement or separation/divorce compared to a wait-list control group. Furthermore, we analysed whether the intervention was also efficacious for participants with milder grief symptoms. A total of 110 participants were mainly recruited by newspaper articles. Average age was 51 years, 77% were separated/divorced, 79% were female. Dropout rate was 11%. Compared to the control group, the intervention resulted in significant reductions in grief (d = 0.81), depression (d = 0.59), psychopathological distress (d = 0.39) (primary outcomes), embitterment (d = 0.37), loneliness (d = 0.37) and an increase in life satisfaction (d = −0.41) (secondary outcomes). These gains were maintained over three months. Improvements were similar among widowed and separated/divorced participants as well as among participants with low, medium or high levels of grief at baseline. Limitations include the self-selective sample and a rather small number of widowed participants. Findings indicate that an internet intervention based on models for coping with grief after bereavement was not only beneficial for widowed but also separated or divorced participants. Furthermore, also participants with lower levels of grief at baseline benefitted from the intervention. This corroborates that indicated prevention efforts for grief are efficacious.