Purpose
Based on the 2020 census, 16.47% of Indonesia’s 270.2 million population were adolescents. Although the adolescence period has been identified as a critical developmental period, there remains a large gap in prevalence data available for mental disorders in Indonesia. Indonesia – National Adolescent Mental Health Survey (I-NAMHS) is the first national representative adolescent mental health survey conducted in Indonesia. It aims to assess mental disorder prevalence in Indonesia as well as several other risks and protective factors identified as contributing to adolescent mental health. This survey is a collaboration between Universitas Gadjah Mada (UGM), the University of Queensland (UQ), and the Johns Hopkins Bloomberg School of Public Health (JHSPH). I-NAMHS fits within a larger, multi-country project, National Adolescent Mental Health Surveys (NAMHS), alongside colleagues in Kenya (K-NAMHS) and Vietnam (V-NAMHS).

Methods
I-NAMHS was a cross-sectional national survey that covered 6,580 households throughout 34 provinces. For each household, an unmarried adolescent aged 10-17 years old and their primary caregiver were interviewed. There were six mental disorders included in I-NAMHS: social phobia and generalized anxiety disorder (GAD) (grouped as anxiety disorder), major depressive disorder, attention-deficit hyperactivity disorder (ADHD), conduct disorder, and post-traumatic stress disorder (PTSD). I-NAMHS used the Diagnostic Interview Schedule for Children, Fifth Edition (DISC-5) to diagnose the disorders which were based on the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Data collection was conducted between 8 March and 30 November 2021 by trained resident enumerators. To respond to the pandemic, data collection was phased out based on the safety level issued by the government. All field staff were equipped with personal protective equipment and had to comply with the strict health protocol.

Results
There were 5,760 households participating in I-NAMHS (response rate at 92.2% after excluding ineligible households). The mean of adolescent age was 13.5 years old and 96.4% attended school. One in three (34.9%) adolescents showed symptoms of a mental disorder in the past 12 months but did not warrant a mental disorder diagnosis, while 5.5% had a mental disorder in the past 12 months. Anxiety disorder was the most common mental disorder experienced by adolescents (3.7%), followed by major depressive disorder, conduct disorder, and PTSD & ADHD at 1.0%, 0.9%, and 0.5%, respectively. Around 1% of adolescents had two or more mental disorders in the past 12 months. No difference in prevalence was seen between males and females or younger and older adolescents.

Conclusions
Anxiety was the most common mental disorder among adolescents 10-17 years old in Indonesia. Still, a big group of adolescents experienced symptoms that were not enough for a mental disorder diagnosis, highlighting vulnerabilities among adolescents in Indonesia. This result was the first nationally representative adolescent mental disorder prevalence in Indonesia, which would contribute to informing the stakeholders in managing adolescent mental health problems in Indonesia.

Sources of Support
The University of Queensland in America (TUQIA) through support from Pivotal Ventures. The funding for NAMHS is administered by The University of Queensland (UQ) which, in turn, provided the funding for I-NAMHS to UGM.