To Örebro University

Cerebral palsy (CP) is a chronic, non-progressive neurological disorder characterized by motor dysfunction believed to be due to disturbances to the developing brain. Several studies have reported that the symptoms of attention-deficit/hyperactivity disorder (ADHD) may be common among individuals with CP. Likewise, clinically diagnosed ADHD has been associated with CP, both within individuals and across siblings. However, it is unknown whether ADHD and CP co-aggregate within extended families, which would further support the presence of shared familial factors in the etiology of the two disorders. To further assess the relationship between ADHD and CP, we conducted a population-wide familial co-aggregation study.

With the use of Swedish national registries we defined a birth cohort born 1960–2010, 5 178,255 individuals, and their biological relatives. We then identified individuals diagnosed with ADHD and/or CP and investigated the familial co-aggregation of ADHD and CP using logistic regression.

ADHD was associated with CP within individuals, adjusted odds ratio (OR) = 2.10 (95% confidence interval: 1.94–2.27), and across relatives with ADHD being associated with CP in mothers, OR = 1.51 (1.20–1.93), fathers, OR = 1.82 (1.44–2.29), full siblings, OR = 1.28 (1.16–1.41), and cousins, OR = 1.11 (1.05–1.17).

Our preliminary findings suggest that ADHD and CP share etiological factors, which may also include genetic factors. This may have consequences for our understanding of both ADHD and CP. Furthermore, shared etiological mechanisms underlying ADHD and CP may indicate that the psychological and pharmacological treatments of ADHD could have a role in the treatment of some of the impairments common among individuals with CP.