- Nearly 30% of the genetic risk factors associated with hypomania in adolescents were also associated with ADHD in childhood and adolescence, according to a study of more than 13,000 twin pairs.
- There was no significant association between environmental factors and the hypomania-ADHD association.
Why this matters
- Up to 10% of youths with hypomania have an increased risk of bipolar disorder (BD), and prior research found increased rates of BD among people with a history of ADHD.
- 13,532 Swedish twin pairs (age, 9 or 12 years) were identified from the Child and Adolescent Twin Study in Sweden.
- 3784 and 3013 participants followed up at 15 and ≥18 years of age, respectively.
- Funding: Swedish Research Council, Swedish Foundation for International Cooperation in Research and Higher Education.
- ADHD symptoms were significantly associated with hypomania at ages 15 and 18 (Pboth<.001>
- 21%-22% (hypomania; age 15) and 13%-29% (hypomania; age 18) of the variance in hypomania was associated with shared genetic risk factors for ADHD traits.
- Environmental factors played a negligible role in the association.
- Genetic overlap with hypomania was greater with hyperactivity-impulsivity (range, 10%-25%) than with inattention (range, 6%-16%).
- Accuracy of ADHD-BD comorbidity rate may be affected by BD misdiagnosis.
Coauthored with Chitra Ravi, MPharm