Objective: The aim of this study is to identify the clinical characteristics in adolescents newly diagnosed with ADHD. Method: Data of patients aged 7 to 17 years diagnosed with ADHD were collected and analyzed. The patients were divided into adolescents aged 13 to 17 years (Group I) and children aged 7 to 12 years (Group II): 592 males and 231 females. Group I consists of 450 participants, and Group II consists of 373 participants. Results: Adolescents were predominantly inattentive (63.8%); most of Group II patients had combined or hyperactive ADHD (70.8%). Learning disorders were more common in adolescents (51.2% vs. 39.7%) and treated mainly with long-acting methylphenidate (MPH), and Group II patients were treated mainly with short- and medium-acting MPH. Newly diagnosed adolescents were less likely to exhibit behavioral comorbidities. Headache and insomnia were reported more in adolescents, and stimulant rebound effect was more in younger children. Conclusion: Although the biological nature of ADHD is similar in both age groups, the primary symptomatology and associated comorbidities are prone to age-dependent changes.
Keywords: ADHD; adolescents ADHD; comorbid psychopathology.