The severity of psychiatric comorbidities associated with ADHD in adults is not linked to the age of onset, a recent Taiwanese study reports.
The aim of this study was to compare the risk of developing comorbid psychiatric disorders in adults aged 17–40 years with early-onset ADHD, late-onset ADHD, and without ADHD, in order to verify the DSM-5 age-of-onset criterion.* Adults with ADHD (n=214; as diagnosed using DSM-IV criteria) and adults without ADHD (n=174) received interviews† to identify the presence of psychiatric comorbidities. Patients with ADHD were further categorised by their recalled age of ADHD onset, falling into early-onset (age <7 years) or late-onset (age 7–12 years) groups. The risk of lifetime psychiatric comorbidities was compared between the ADHD and control groups using Cox proportional hazards regression analyses.
Results of this study indicated that adults with early-onset ADHD experienced significantly more past and current hyperactive symptoms than adults in the late-onset group (p<0.001 for both). Overall, adults with ADHD were more likely to develop a range of psychiatric disorders compared with adults without ADHD, including conduct disorder, oppositional defiant disorder, mood disorders, anxiety disorders, substance use disorders and sleep disorders. Furthermore, after adjustment for age and sex, researchers identified no differences in the risk of these comorbidities relating to the age of onset of ADHD.
Ultimately, the results of this study demonstrate that adults with ADHD are at significant risk of developing psychiatric comorbidities, and suggest that the time of (recalled) ADHD onset does not alter this risk. Although it is important to note that this conclusion is based on the recalled, and potentially inaccurate, onset of ADHD by patients in a single geographical location (Taiwan), this study further validates the DSM-5 ADHD age-of-onset criterion.
*Diagnostic and Statistical Manual of Mental disorders, 5th Edition; age-of-onset criterion: maximum age of onset of ADHD for individuals aged ≥17 years is 12 years
†Interviews conducted using a modified version of the Chinese Kiddie-Schedule for Affective Disorders and Schizophrenia-Epidemiological version (K-SADS-E)
Lin YJ, Yang LK, Gau SSF. Psychiatric comorbidities of adults with early- and late-onset attention-deficit/hyperactivity disorder. Aust N Z J Psychiatry 2016; 50: 548-556.