Association between parental ADHD and adverse offspring outcomes: Evidence from a nationwide Swedish register-based study

The potential associations between parental ADHD and a broad spectrum of offspring health outcomes remain uncertain. We explored associations between parental ADHD and multiple adverse outcomes in offspring. We used linked Swedish national registers to identify all individuals born in Sweden between 2000 and 2014 (N = 1,164,580) and followed them from birth until emigration, death, or December 31, 2020. After matching, 56,853 individuals with parental ADHD and 544,716 individuals without parental ADHD were included in the analysis. Parental ADHD was identified through ADHD diagnoses or ADHD medication prescriptions. Offspring of parents with ADHD were matched to ten individuals whose parents had no ADHD diagnosis. Stratified Cox regression models with robust standard errors were used to estimate associations between parental ADHD and 24 offspring outcomes. Offspring of parents with ADHD had higher rates of most adverse outcomes, compared with those without parental ADHD. Parental ADHD was associated with an increased rate of offspring psychiatric disorders (range of hazard ratios [HRs]: 1.49 for intellectual disability - 4.47 for ADHD), behavioral outcomes (range of HRs: 1.08 for falls - 1.82 for assault/victimization), and somatic disorders (range of HRs: 1.04 for type 1 diabetes-2.47 for sleep disorder). After adjusting for offspring lifetime ADHD, associations weakened but remained significant, except for intellectual disability and epilepsy. Rates were elevated for both maternal and paternal ADHD and highest when both parents with ADHD. Parental ADHD was associated with elevated risks of a broad range of adverse outcomes in offspring, encompassing psychiatric, behavioral, and somatic conditions. These findings highlight the broad intergenerational impact of ADHD and the need for early identification and family-focused preventive strategies.