A sharp general linear decrease in the levels of hyperactive/impulsive symptoms was observed from ages 8 to 16 years in this population-based sample of twins. A less pronounced decrease was observed for inattention symptoms. Important interindividual differences were detected (faster or slower decreases vs persistence, or even increases in inattention symptoms for a subset of children). These interindividual differences in the developmental course of symptoms were mostly explained by genetic influences, mostly independent from those influencing the baseline level of symptoms. Developmental models will be crucial in identifying genetic variants and specific environmental influences explaining why some children remit from ADHD, whereas others persist. The confirmation of large genetic influences on the developmental course of ADHD symptoms is important for both clinicians and patients. For clinicians, the maintenance or increase in symptoms (a decline being normative in the population) might represent a marker of vulnerability reflecting genetic liability and warrant closer follow-up. It also raises the question of the necessity to inform patients and their relatives about the higher risk of persistence in families of index cases with persistent symptoms.
Pingault JB, Viding E, Galéra C, Greven CU, Zheng Y, Plomin R, Rijsdijk F.
Genetic and Environmental Influences on the Developmental Course of
Attention-Deficit/Hyperactivity Disorder Symptoms From Childhood to Adolescence.
JAMA Psychiatry. 2015 May 6. doi: 10.1001/jamapsychiatry.2015.0469. [Epub ahead