Objective: We examined long-term outcomes of attention-deficit/hyperactivity disorder (ADHD) in a population-based sample of childhood ADHD cases and controls, prospectively assessed as adults.
Methods: Adults with childhood ADHD and non-ADHD controls from the same birth cohort (N = 5718) were invited to participate in a prospective outcome study. Vital status was determined for birth cohort members. Standardized mortality ratios (SMRs) were constructed to compare overall and cause-specific mortality between childhood ADHD cases and controls. Incarceration status was determined for childhood ADHD cases. A standardized neuropsychiatric interview was administered.
Results: Vital status for 367 childhood ADHD cases was determined: 7 (1.9%) were deceased, and 10 (2.7%) were currently incarcerated. The SMR for overall survival of childhood ADHD cases versus controls was 1.88 (95% confidence interval [CI], 0.83-4.26; P = .13) and for accidents only was 1.70 (95% CI, 0.49-5.97; P = .41). However, the cause-specific mortality for suicide only was significantly higher among ADHD cases (SMR, 4.83; 95% CI, 1.14-20.46; P = .032). Among the childhood ADHD cases participating in the prospective assessment (N = 232; mean age, 27.0 years), ADHD persisted into adulthood for 29.3% (95% CI, 23.5-35.2). Participating childhood ADHD cases were more likely than controls (N = 335; mean age, 28.6 years) to have ≥1 other psychiatric disorder (56.9% vs 34.9%; odds ratio, 2.6; 95% CI, 1.8-3.8; P < .01).
Conclusions: Childhood ADHD is a chronic health problem, with significant risk for mortality, persistence of ADHD, and long-term morbidity in adulthood.