A new study has confirmed that young smokers with attention deficient hypersensitivity disorder (ADHD) are at an increased risk of becoming seriously addicted to nicotine.
Massachusetts General Hospital researchers have also found that individuals with more ADHD-related symptoms are at greater risk of becoming dependent on nicotine than those with fewer symptoms.
"Knowing that ADHD increases the risk of more serious nicotine addiction stresses the importance of prevention efforts aimed at adolescents and their families," said Dr Timothy Wilens, director of the Substance Abuse.
"It also gives us clues about how the neurotransmitter systems involved in ADHD and tobacco use may be interacting," he added.
During the study, the participants were taken from two long-term studies - one in boys and the other in girls - that analysed a variety of factors in children and adolescents with ADHD compared with a matched control group.
The researchers found that smokers with ADHD began using tobacco about a year and a half sooner than did control group members, while moderate or higher levels of nicotine dependence were reported by 21 percent of AHDH participants but less than 1 percent of controls.
The study suggests biological mechanisms that may underlie both ADHD and nicotine dependence.
"We've already shown that nicotine-based medications can treat ADHD symptoms, and it's known that the children of mothers who smoked during pregnancy are at greater risk of ADHD," said Wilens.
"It looks like interplay between the dopamine system, more substantially related to ADHD and addiction, and the cholinergic system related to smoking is probably important.
"Further investigations of the neurobiological aspects and potential issues of self-medication should help us better understand what is going on," he added.
The study appears in the Journal of Pediatrics.