Trends in the Incidence and Lethality of Suicidal Acts in the United States, 2006 to 2015.

Importance: Understanding changes in the incidence rates and lethality of suicidal acts may explain increasing suicide rates. Objective: To examine trends in the incidence rates and lethality of suicidal acts from 2006 to 2015 among persons aged 10 to 74 years. Design, Setting, and Participants: This cross-sectional study was conducted from May 2, 2018, to January 30, 2019. Medically treated nonfatal suicide attempts were identified from the 2006 to 2015 Nationwide Inpatient Sample and Nationwide Emergency Department Sample databases. Suicides were identified from the 2006 to 2015 mortality files of the National Vital Statistics System. Main Outcomes and Measures: The incidence rate of suicidal acts was calculated by dividing the number of total suicidal acts by the US population. Lethality was measured through the case fatality rates (CFRs) of suicidal acts by dividing the number of suicides by the total number of suicidal acts. Results: A total of 1 222 419 (unweighted) suicidal acts, which included both suicides and nonfatal suicide attempts, were identified from 2006 to 2015. Overall, the incidence rates of total suicidal acts increased 10% from 2006 to 2015 (annual percentage change [APC], 0.8%; 95% CI, 0.3%-1.3%), and the CFRs of suicidal acts increased 13% during the 2006 to 2015 period (APC, 2.3%; 95% CI, 1.3%-3.3%). In subgroup analyses, incidence rates increased by 1.1% (95% CI, 0.6%-1.6%) per year for female individuals during the 2006 to 2015 period but remained stable for male individuals. The CFRs increased for both sexes (APC, 5.0% [95% CI, 3.1%-6.9%] since 2010 for female individuals; 1.6% [95% CI, 0.6%-2.5%] since 2009 for male individuals). Incidence rates increased among adolescents from 2011 to 2015 and among older adults aged 65 to 74 years throughout the 2006 to 2015 period. Conversely, the CFRs increased since 2009 among persons aged 20 to 44 years (APC, 3.7%; 95% CI, 2.5%-5.0%) and since 2012 for those aged 45 to 64 years (APC, 2.7%; 95% CI, 0.0%-5.4%). Persons aged 20 to 44 years and 45 to 64 years experienced increases in suicidal acts by more lethal means, whereas adolescents and older adults aged 65 to 74 years showed increased incidence by all means. Conclusions and Relevance: This study found increased suicidal acts among female persons, adolescents, and older adults aged 65 to 74 years, implying the need to address emerging or exacerbating suicide risk factors for these populations. The findings on the increased lethality particularly among persons aged 20 to 64 years highlighted the need to reduce access to materials that could be used as lethal means among persons at risk of suicide. These findings on population-level epidemiologic patterns can be used to guide the development of comprehensive suicide prevention strategies.