The coronavirus disease 2019 (COVID-19) pandemic, a global health crisis, profoundly impacted all aspects of daily life. Adolescence, a pivotal stage of psychological and social development, is heavily influenced by the psychosocial and socio-cultural context. Hence, it is imperative to thoroughly understand the psychosocial changes adolescents experienced during the pandemic and implement effective management initiatives. We examined the incidence rates of depressive and anxiety disorders among adolescents aged 10-19years globally and regionally. We utilized data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 to compare pre-pandemic (2018-2019) and pandemic (2020-2021) periods. Our investigation covered 204 countries and territories across the six World Health Organization regions. We conducted a comprehensive literature search using databases including PubMed/MEDLINE, Scopus, and Google Scholar, employing search terms such as "psychosocial", "adolescent", "youth", "risk factors", "COVID-19 pandemic", "prevention", and "intervention". During the pandemic, the mental health outcomes of adolescents deteriorated, particularly in terms of depressive and anxiety disorders. According to GBD 2021, the incidence rate of anxiety disorders increased from 720.26 [95% uncertainty intervals (UI) = 548.90-929.19] before the COVID-19 pandemic (2018-2019) to 880.87 per 100,000 people (95% UI = 670.43-1132.58) during the COVID-19 pandemic (2020-2021). Similarly, the incidence rate of major depressive disorder increased from 2333.91 (95% UI = 1626.92-3138.55) before the COVID-19 pandemic to 3030.49 per 100,000 people (95% UI = 2096.73-4077.73) during the COVID-19 pandemic. This worsening was notably pronounced in high-income countries (HICs). Rapid environmental changes, including heightened social anxiety, school closures, economic crises, and exacerbated racism, have been shown to adversely affect the mental well-being of adolescents. The abrupt shift to remote learning and the absence of in-person social interactions heightened feelings of loneliness, anxiety, sadness, and stress among adolescents. This change magnified existing socioeconomic disparities, posing additional challenges. These complexities profoundly impact adolescents' well-being, especially vulnerable groups like those from HICs, females, and minorities. Acknowledging the underreporting bias in low- to middle-income countries highlights the importance of addressing these mental health alterations in assessments and interventions within these regions as well. Urgent interventions are crucial as the pandemic-induced mental stress may have lasting effects on adolescents' mental health.