Objectives: The aims of the present study were to examine the current psychiatric comorbidity among children and adolescents with and without persistent attention-deficit hyperactivity disorder (ADHD) as compared to school controls, and to determine the factors predicting psychiatric comorbidity.

Method: The sample included 296 patients (male, 85.5%), aged 11–17, who were diagnosed with DSM-IV ADHD at the mean age of 6.7 ± 2.7 years and 185 school controls. The ADHD and other psychiatric diagnoses were made based on clinical assessments and confirmed by psychiatric interviews. The ADHD group was categorized into 186 patients (62.8%) with persistent ADHD and 110 (37.2%) without persistent ADHD.

Results: Compared to the controls, the two ADHD groups were more likely to have oppositional defiant disorder (ODD), conduct disorder (CD), tics, mood disorders, past and regular use of substances, substance use disorders and sleep disorders (odds ratios (ORs) = 1.8–25.3). Patients with persistent ADHD had higher risks for anxiety disorders, particularly specific phobia than the controls. Moreover, patients with persistent ADHD were more likely to have ODD than their partially remitted counterparts. Advanced analyses indicated that more severe baseline ADHD symptoms predicted ODD/CD at adolescence; longer methylphenidate treatment duration was associated with an increased risk for tics and ODD/CD at adolescence; and older age predicted higher risks for mood disorders and substance use disorders.

Conclusion: Reduced ADHD symptoms at adolescence may not lead to decreased risks for psychiatric comorbidity, and identification of severe ADHD symptoms at childhood and age-specific comorbid patterns throughout the developmental stage is important to offset the long-term adverse psychiatric outcomes of ADHD.