Investigating risk of self-harm and suicide on anniversaries after bereavement by suicide and other causes: a Danish population-based self-controlled case series study.

Aims: To investigate mechanisms of suicide risk in people bereaved by suicide, prompted by observations that bereaved people experience higher levels of distress around dates of emotional significance. We hypothesised that suicide-bereaved first-degree relatives and partners experience an increased risk of self-harm and suicide around dates of (i) anniversaries of the death and (ii) the deceased's birthday, compared with intervening periods.

Methods: We conducted a self-controlled case series study using national register data on all individuals living in Denmark from 1 January 1980 to 31 December 2016 and who were bereaved by the suicide of a first-degree relative or partner (spouse or cohabitee) during that period, and who had the outcome (any episode of self-harm or suicide) within 5 years and 6 weeks of the bereavement. We compared relative incidence of suicidal behaviour in (i) the first 30 days after bereavement and (ii) in the aggregated exposed periods (6 weeks either side of death anniversaries; 6 weeks either side of the deceased's birthdays) to the reference (aggregated unexposed intervening periods). As an indirect comparison, we repeated these models in people bereaved by other causes.

Results: We found no evidence of an elevated risk of suicidal behaviour during periods around anniversaries of a death or the deceased's birthdays in people bereaved by suicide (adjusted incidence rate ratio [IRR_adj] = 1.00; 95% confidence interval [CI] = 0.87-1.16) or other causes (IRR_adj = 1.04; 95% CI = 1.00-1.08) compared with intervening periods. Rates were elevated in the 30 days immediately after bereavement by other causes (IRR_adj: 1.95, 95% CI: 1.77-2.22).

Conclusions: Although people bereaved by suicide are at elevated risk of self-harm and suicide, our findings do not suggest that this risk is heightened around emotionally significant anniversaries. Bereavement care should be accessible at all points after a traumatic loss as needs will differ over the grief trajectory.