Psychiatrist density and risk of suicide: A multilevel case-control study based on a national sample in Taiwan

Aim No previous studies, to our knowledge, have investigated the association between psychiatrist density and suicide, accounting for individual- and area-level characteristics. Methods We investigated all suicide cases in 2007-2017 identified from the national cause-of-death data files, with each suicide case matched to 10 controls by age and sex and each suicide case/control assigned to one of the 355 townships across Taiwan. Our primary outcome was the odds ratio (OR) of suicide and its 95% confidence interval (CI) estimated via multilevel models, which included both individual- and area-level characteristics. Townships with no psychiatrists were compared with the quartiles of townships with psychiatrists (density per 100,000 population): quartile 1 (Q1) (0.01–3.02); quartile 2 (Q2) (3.02–7.20); quartile 3 (Q3) (7.20–13.82); and quartile 4 (Q4) (>13.82). Results A total of 40,930 suicide cases and 409,300 age- and sex-matched controls were included. We found that increased psychiatrist density was associated with decreased suicide risk (Q1: adjusted OR [aOR], 0.95 [95% CI, 0.90–1.01]; Q2: aOR, 0.90 [95% CI, 0.85–0.96]; Q3: aOR, 0.89 [95% CI, 0.83–0.94]; Q4: aOR, 0.89 [95% CI, 0.83–0.95]) after adjusting for individual-level characteristics (employment state, monthly income, physical comorbidities, and the diagnosis of psychiatric disorders) and area socioeconomic characteristics. Conclusions The psychiatrist density–suicide association suggests an effect of increased availability of psychiatric services on preventing suicide. Suicide prevention strategies could usefully focus on enhancing local access to psychiatric services.