Trends in suicide methods in Switzerland from 1969 to 2018: an observational study

BACKGROUND: Suicide is a serious societal and health problem. We examined changes in rates of completed suicides in Switzerland between 1969-2018 with particular regard to different methods of suicide used in different subgroups of the resident population. METHODS: We used data of the Swiss cause of death statistics and Poisson regression models to analyse annual incidence rates and calendar time trends of specific suicide methods used in population subgroups by sex (men vs women), age (10-29, 30-64, >64 years), and nationality (Swiss vs other citizenship). RESULTS: There were 64,996 registered suicides between 1969 and 2018. Across these 5 decades, the overall suicide rate was higher in men than in women (incidence rate ratio [IRR] 2.62, 95% confidence interval [CI] 2.58-2.67), in Swiss citizens than in foreigners (IRR 2.02; 95% CI 1.97-2.07), and in older residents (>64 years) than in the age groups 30-64 years (IRR 1.35, 95% CI 1.32-1.37) and 10-29 years (IRR 2.37, 95% CI 2.32-2.43). After peaking in the 1980s, the overall suicide rate had declined in all of these population subgroups, with flattening trends over most recent years. The most common specific methods of suicide were hanging (accounting for 26.7% of all suicides) and firearms (23.6%). The rates of the specific suicide methods were usually higher in men, in Swiss citizens and in older residents, and they had typically declined over most recent decades in the population subgroups examined. However, some methods diverged from this general pattern, at least in some population subgroups. For instance, railway suicides most recently increased in younger and in male residents whereas suicides by gas and by drowning were only at a low level after rapid declines in the last millennium. CONCLUSIONS: Restricting access to lethal means (e.g., detoxification of domestic gas), improvements in health care and media guidelines for responsible reporting of suicides are possible explanations for the generally declining suicide rates in Switzerland. Whereas some methods (e.g., poisoning by gases or drowning) had become rare, others continue to account for many suicides every year, at least in some population subgroups (e.g., firearms in older Swiss men or railway suicides in younger and in male residents). As different methods of suicide are chosen by different people or subgroups of the population, preventive efforts should include differentiated strategies and targeted measures to further reduce suicides in Switzerland and elsewhere.