Mental health among adolescents is a critical public health concern. This study aimed to investigate trends in suicidal ideation, suicide attempts, and sleep disturbances among Chinese high school students from 2014 to 2023, encompassing the COVID-19 pandemic period. Data were drawn from five waves (2014, 2016, 2018, 2021, 2023) of the School-based Chinese Adolescents Health Survey (SCAHS) in Guangdong province. A total of 110,193 high school students in grades 7-12 were included in the analysis. The weighted prevalence and its trends of suicidal ideation, suicide attempt, and sleep disturbance was analyzed. From 2014 to 2018, the weighted prevalence of suicidal ideation increased from 16.3% to 18.0%, suicide attempt increased from 2.8% to 3.7%, and sleep disturbances increased from 28.0% to 29.1%. These trends peaks in 2021 (18.5%, 4.2%, and 31.5% for suicidal ideation, suicide attempt and sleep disturbance, respectively). By 2023, all prevalence showed significant decreases from their peaks: suicidal ideation, suicide attempt and sleep disturbance declined to 17.4%, 3.4%, and 27.7, respectively. Students aged 11-14 years and girls consistently showed higher prevalence in suicidal behaviors throughout study period. This study reveals fluctuating trends in suicidal behaviors and sleep disturbance among high school students over a decade in China, with pronounced effects during the COVID-19 pandemic. While recent declines are encouraging, the persistent burden, particularly among girls and students aged 11-14 years, underscores the urgent need for targeted mental health interventions for these high-risk groups, as well as continued surveillance to inform public health policy and practice.
