Association Between Smoking, Brain Activity, Genes, and ADHD

The study investigated the underlying mechanisms of smoking in young adults by examining the associations between smoking, brain activity, dopamine genes, and attention deficit hyperactivity disorder (ADHD). Four groups of young adults were recruited: (1) smokers with ADHD; (2) nonsmokers with ADHD; (3) normative control smokers; and (4) normative control nonsmokers. Smoking was assessed via questionnaires and salivary cotinine levels. Brain activity was examined via functional Magnetic Resonance Imaging (fMRI). Each nonsmoker underwent an fMRI scan during an experimental task consisting of mathematical problems. Smokers underwent two fMRI scans during similar experimental tasks under the following two conditions: (1) after smoking a cigarette and (2) after overnight abstinence. The association between the DRD4-7 repeat allele and smoking was explored.