Canadian researchers found that ADHD in children is genetically linked to smoking. According to the study, kids with ADHD are two times more prone to start smoking.
A research published in Archives of Disease in Childhood has identified a genetic marker that makes kids with ADHD more likely to pick up smoking. Researchers believe their study shows that the “cognitive deficits” the brain experiences in childhood because of ADHD leaves the door open for smoking later on.
The team of scientists collected DNA samples from 454 children aged 6 to 12, all with an ADHD diagnosis. They also asked their mothers if they smoked during pregnancy. Only 394 mothers responded to that question, and 171 confessed they smoked while they were pregnant. The study also found a connection between smoking during pregnancy and ADHD in kids later on.
“This may also explain why children with ADHD are more likely to be born to mothers who smoked during pregnancy” said Dr. Ridha Joober, lead researcher with the Douglas Mental Health University Institute in Montreal. “This genetic variant – and there are probably many others – increases the risk for smoking in mothers and the risk for ADHD in their children”.
Researchers looked at five DNA sequence variations, also known as SNPs (single nucleotide polymorphisms) in the genes known to determine various behaviors among smokers. Parents and siblings also gave DNA samples. One of the variations in the DNA sequences was linked to the number of cigarettes one smokes a day and ADHD.
Children that presented the SNP marker are more likely to develop behavioral problems and have issues focusing. The gene that links ADHD and smoking is creating a gateway for tobacco later on. Moreover, according to study authors the genes are more likely to be behind ADHD than environmental factors during pregnancy such as smoke exposure.
“For a long time, smoking during pregnancy has been associated with a higher risk of ADHD in the offspring” said Dr. Joober. “However, the nature of this association was very much debated and one the hypotheses was that two [results] are due to common factors that increase smoking in mothers and ADHD in their children” the study author explained adding that this “shows for the first time that this common link could be genes”.