Suicide occurrence within the first year after an initial dementia diagnosis: A Nationwide cohort study in Taiwan

A dementia diagnosis is a critical and distressing period that may precipitate suicide, yet nationwide cohort studies in Asia examining suicide occurrence within the first year following diagnosis remain scarce.

To examine the 1-year suicide occurrence following a new dementia diagnosis compared with individuals without dementia and identified high-risk subgroups.

A total of 489,178 patients newly diagnosed with dementia between 2011 and 2020 were identified, along with a comparison cohort of 1,956,712 age-, sex-, and index date-matched individuals without dementia, from the Taiwan's National Health Insurance Research Database (NHIRD). All participants were linked to the Taiwan Death Registry to ascertain suicide deaths. Cause-specific hazard models were used to estimate adjusted hazard ratios (AHRs) for suicide overall and across subgroups stratified by sex, age, psychiatric comorbidities, suicide method, and follow-up period.

During 1-year follow-up, suicide rates were higher in the dementia than comparison cohort (90.03 vs. 39.28 per 10⁵ person-years; AHR 1.37, 95% CI 1.20-1.56). The highest hazard of suicide was observed among younger male patients with dementia (AHR 2.39, 95% CI 1.33-4.28). Elevated hazard of suicide was associated with psychiatric comorbidities, the early post-diagnostic period, and suicide by jumping, hanging, or poisoning, although these associations differed by sex.

Patients with dementia had a higher incidence and hazard of suicide than individuals without dementia, with magnitudes varying by sex, age, psychiatric comorbidities, disease duration, and suicide method. Prevention strategies should consider these profiles to target individuals with an elevated hazard of suicide.