Temporal trends and patterns in suicidal ideation among adolescents in 23 countries from 2003 to 2021

Although suicidal ideation is a significant issue among adolescents, previous studies have largely relied on cross-sectional data collected at a single time point or have been limited to individual countries, providing limited insight into temporal trends across diverse populations. Therefore, we aimed to examine temporal trends in suicidal ideation among adolescents across 23 countries. We analyzed data from the Global School-Based Student Health Survey (2003-2021), which included adolescents aged 13-15 years in 23 countries. Each participant participated in multiple surveys, and survey years varied by country. Prior to trend estimation, we compared linear and quadratic fits where more than three surveys were available to identify near-linear patterns. Temporal trend was quantified as the average annual percentage change (AAPC), which was calculated by weighted log-linear regression on the log prevalence rates of the survey years, applied separately to boys and girls. The study analyzed 185,941 school-attending adolescents (46.45% male) across 23 countries. The prevalence of suicidal ideation showed significant upward trends in six countries: Myanmar (AAPC, 32.04%/year; 2007-2016), Guyana (AAPC, 8.88%/year; 2010-2014), Saint Vincent and the Grenadines (AAPC, 3.87%/year; 2007-2018), Mongolia (AAPC, 3.67%/year; 2010-2013), Bolivia (AAPC, 3.02%/year; 2012-2018), and Seychelles (AAPC, 2.54%/year; 2007-2015). Conversely, five countries exhibited significant declines, including Benin (AAPC, -8.60%/year; 2009-2016), Kuwait (AAPC, -6.40%/year; 2011-2015), and the Maldives (AAPC, -4.33%/year; 2009-2014). Sex-specific differences in trends were nominally significant (p < 0.05) in six countries-Benin, Kuwait, Argentina, Saint Vincent and the Grenadines, Thailand, and Guyana-but only two (Saint Vincent and the Grenadines and Thailand) remained statistically significant after Bonferroni correction. In five of these countries (excluding Guyana), girls exhibited more unfavorable patterns, showing either a greater increase or a smaller decrease in suicidal ideation compared to boys. This study highlights divergent trends in adolescent suicidal ideation across 23 countries, with rising prevalence in some regions and notable sex differences. The findings underscore the need for continued surveillance and context-specific mental health interventions.