Age-Stratified Patterns of Suicide Methods in Bipolar Disorder: A Nationwide Cohort Study

Age-stratified suicide methods in bipolar disorder remain underexplored. This study compared method selection between suicide decedents with bipolar disorder and the general population.

We identified 47,488 individuals with bipolar disorder between 2003 and 2023 from Taiwan's nationwide health database and linked mortality records to ascertain suicide deaths. Using a decedent-only design, we compared the distribution of suicide methods between suicide decedents with bipolar disorder and those from the general population. Age-stratified (< 30, 30-49, 50-64, and ≥ 65 years) multivariable logistic regression analyses were performed with adjustment for sex, age at death, urbanization level, and employment status.

Among 1452 suicide deaths over 478,729 person-years (incidence: 303.3 per 100,000), the most common methods were hanging (28.0%), charcoal burning and other gas poisoning (20.9%), jumping from a high place (18.0%), drug overdose (16.9%), and drowning (11.4%). Suicide decedents in the bipolar cohort had higher odds of drowning (adjusted odds ratio [aOR]: 1.70, 95% confidence interval [CI]: 1.44-2.00) and jumping from a high place (aOR: 1.31, 95% CI: 1.14-1.50) but lower odds of charcoal burning and other gas poisoning (aOR: 0.69, 95% CI: 0.60-0.79) and hanging (aOR: 0.87, 95% CI: 0.77-0.98) than did general-population decedents (n = 81,159). Age-stratified analyses showed charcoal burning concentrated in younger and middle-aged decedents, drowning consistently elevated across age strata, and jumping elevated in middle-aged and older decedents.

Individuals with bipolar disorder who die by suicide exhibit distinct, age-dependent patterns of suicide methods. Therefore, prevention strategies should be tailored to both age groups and methods.