Diagnostic and Statistical Manual for Mental Disorders – 5th edition (DSM-5) criteria for the diagnosis of adult ADHD require symptom onset before 12 years of age. However, findings of a prospective longitudinal study conducted in Brazil question the assumption that adult ADHD is a continuation of the childhood disorder. The majority of adults who otherwise met the DSM-5 criteria for ADHD in this study did not experience early symptom onset; conversely, symptoms in most children with ADHD did not persist beyond adolescence.
A cohort of 5249 children born in Brazil in 1993 was assessed for ADHD at 11 years of age using the Strengths and Difficulties Questionnaire, parent-report and self-report. At 18–19 years of age, a second assessment for ADHD was performed using the DSM-5, omitting the age-at-onset criterion. ADHD was diagnosed in 8.9% of children (n=393) and 12.2% of young adults (n=492).
Persistence of ADHD into young adulthood was reported in 17.2% of children. Conversely, in young adults with ADHD, only 12.6% were considered to have had ADHD as children. At the second assessment, individuals with either a persistent or new diagnosis of ADHD demonstrated higher rates of comorbidities, suicide attempts, criminality and traffic incidents compared with young adults without ADHD.
A potential limitation of the study was the use of parent-reported responses for childhood diagnosis of ADHD, whereas diagnosis in young adults was based on self-reports; however, this reflects a shift in responsibilities also seen in real-world practice. Intriguingly, the findings suggest the existence of two syndromes, childhood-onset ADHD and late-onset ADHD.
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Caye A, Rocha TB, Anselmi L, et al. Attention-deficit/hyperactivity disorder trajectories from childhood to young adulthood: evidence from a birth cohort supporting a late-onset syndrome. JAMA Psychiatry 2016; 73: 705-712.