This nationwide Finnish cohort study examined the co-occurrence of ASD, ADHD, tic disorder (TD), and OCD in individuals with eating disorders (AN, BN, other/unspecified EDs; N=4,240, born 1991–2001) versus population controls (N=16,494), and extended the analysis to full and half siblings (N=36,301) to assess familial aggregation.
Individuals with AN had markedly elevated odds of ASD (OR 6.62), ADHD (OR 3.30), and OCD (OR 10.67) vs. controls. Other/unspecified EDs showed the highest ASD odds overall, reaching OR 32.40 in males. Full siblings of AN probands had ~2× odds for ASD and ~3× odds for OCD compared to siblings of controls; siblings of other/unspecified ED probands had 2–3× elevated odds for ASD, ADHD, TD, and OCD.
The study is limited to clinically diagnosed (ICD-10) cases in Finnish registers, likely underestimating true prevalence. The cohort spans births 1991–2001 in a single country, limiting generalizability. BN did not show statistically significant associations, possibly reflecting smaller subgroup power.
Screen individuals with eating disorders—especially AN and atypical/unspecified EDs—for ASD, ADHD, and OCD, as odds are dramatically elevated (up to 10-fold for OCD). Consider neurodevelopmental evaluation for their full siblings as well, given 2–3-fold familial risk.
