RESUMEN
OBJECTIVE: To compare the characteristics of childhood-onset versus late-onset Attention Deficit Hyperactivity Disorder (ADHD) in a sample of treatment-seeking patients. METHOD: Among total of 101 adult patients who were recently diagnosed for ADHD, using the Diagnostic Interview for Adult ADHD (DIVA 2.0), 56 subjects exhibited childhood-onset ADHD, versus 45 displayed late-onset ADHD. Both groups were compared according to their sociodemographic, clinical, and neuropsychological features, providing crude (OR) and adjusted odds ratios (aOR), and their 95% confidence intervals [95% CI]. RESULTS: Compared to late-onset ADHD, patients with childhood-onset had a lower educational score, (OR = 0.52; 95% CI [0.35, 0.76]), a greater score of impulsivity (aOR = 1.09; 95% CI [1.03, 1.16]), an increased number of hyperactive-impulsive ADHD symptoms (aOR = 1.9; 95% CI [1.46, 2.47]), and higher rates childhood trauma (aOR = 1.07; 95% CI [1.01, 1.13]), cannabis use disorder (aOR = 1.07; 95% CI [1.01, 1.13]), and working memory impairment. No difference was observed concerning age, sex, psychiatric symptoms, quality of life, and autonomy. CONCLUSION: Childhood-onset adult ADHD displayed a more severe profile, relative to late-onset ADHD.