Recently, a growing number of adolescents have been afflicted with mental disorders, with annual morbidity rates on the rise. This trend has been exacerbated by the global coronavirus disease 2019 (COVID-19) pandemic, leading to a surge in suicide and self-harm rates among this demographic. To investigate the impact of the COVID-19 pandemic on adolescent bipolar disorder (BD), along with the underlying factors contributing to heightened rates of suicide and self-harm among adolescents. A comprehensive statistical analysis was conducted utilizing clinical interviews and self-reports obtained from patients or their guardians. Diagnostic criteria for BDs were based on the Diagnostic and statistical manual of mental disorders, international classification of diseases-11, and the National institute of mental health research domain criteria. Statistical analyses were performed using SPSS 26.0 software, with significance set at P < 0.05. A cohort of 171 adolescents diagnosed with BD between January 1, 2018, and December 31, 2022, was included in the analysis. The gender distribution was 2.8:1 (female to male), with ages ranging from 11 to 18 years old. Major factors contributing to adolescent BDs included familial influences, academic stress, genetic predisposition and exposure to school-related violence. Notably, a significant increase in suicide attempts and self-harm incidents was observed among adolescents with BD during the COVID-19 pandemic. Statistical analysis indicated that the pandemic exacerbated familial discord and heightened academic stress, thereby amplifying the prevalence of suicidal behavior and self-harm among adolescents. The COVID-19 pandemic has exacerbated familial tensions and intensified the incidence of suicide and self-harm among adolescents diagnosed with BD. This study underscores the urgent need for societal, familial and educational support systems to prioritize the well-being of adolescents and offers valuable insights and guidelines for the prevention, diagnosis and treatment of adolescent BDs.