Genetic variants that increase the risk of attention deficit hyperactivity disorder (ADHD) may also contribute to worse working memory performance in children . This is the main conclusion of a study led by researchers from the Barcelona Institute for Global Health (ISGlobal, a centre supported by the ”la Caixa” Foundation, whose findings were recently published in Psychological Medicine.
ADHD is a neurodevelopmental disorder that arises in childhood. In addition to inattention and hyperactivity, the symptoms of this condition include certain cognitive difficulties such as poor working memory performance . “Working memory is a crucial capacity not only for storing recent information, but also for processing it correctly,” commented Silvia Alemany, coordinator of the study and researcher at ISGlobal. “In this study, we wanted to determine whether genetic variants linked to ADHD were also expressed in cognitive functions such as memory and attention during childhood.”
The team behind the study used data from 1,667 healthy children between the ages of seven and ten years who were participating in BREATHE, a project that studies the impact of environmental pollution on children’s cognitive development. Over a one-year period, the researchers analysed the working memory and attention performance of the sample population, while also assessing the children’s polygenic risk of developing ADHD.
The findings showed that the higher a child’s genetic susceptibility for ADHD, the lower his or her working memory performance. “We observed that genetic susceptibility linked to ADHD was associated with poorer working memory performance in children who, for the most part, did not show symptoms of this disorder,” commented Sofia Aguilar-Lacasaña, lead author of the study and researcher at ISGlobal. “However, genetic variants associated with ADHD did not seem to affect the children’s cognitive-developmental trajectory as assessed over the entire one-year period. The children’s scores improved by the end of the year regardless of their genetic susceptibility for ADHD, although those who had high susceptibility had worse scores at the start of the study period.”
Stronger Association in Boys Than in Girls
“Interestingly, when the data were broken down by sex, we saw that the effects of higher ADHD risk on working memory performance were more pronounced in boys than in girls,” commented Aguilar-Lacasaña. While it is true that rates of ADHD are higher in boys, the findings could possibly be explained by genetic susceptibility for ADHD operating via different mechanisms in boys and girls.
This is the first study to examine the association between polygenic risk for ADHD and cognitive development over a one-year period. “Our findings enhance our understanding of the genetic origin of working memory capacity and suggest that genetic risk variants for ADHD may contribute to worse memory performance,” concluded Alemany.
Aguilar-Lacasaña, S., Vilor-Tejedor, N., Jansen, P., López-Vicente, M., Bustamante, M., Burgaleta, M., Alemany, S. (2020). Polygenic risk for ADHD and ASD and their relation with cognitive measures in school children . Psychological Medicine, 1-9. doi:10.1017/S0033291720003189