New research suggests young people with attention deficit
hyperactivity disorder (ADHD) who smoke are at significantly
greater risk of developing drug and alcohol misuse problems than
those who do not.
Previous research has shown that cigarette
smoking is a gateway for the subsequent alcohol and drug misuse and
dependence.
This study, published online today by the British Journal
of Psychiatry, shows that smokers with ADHD are at especially
high risk.
The researchers studied 651 young people in
America – 213 with ADHD and 438 without (the control group). They
interviewed the youths to assess their smoking and substance use
habits, and followed them up over a period of 10 years. Among these
youths, the overall rate of smoking was 28% (34% in the ADHD group
and 25% in the control group). The group with ADHD started smoking
earlier – the average age of onset for them was 13.9 years,
compared to 15.4 years for the control group.
At the age of 23, rates of alcohol dependence
were 7% for non-smokers without ADHD, 10% for non-smokers with
ADHD, 18% for smokers without ADHD and 35% for smokers with ADHD.
Similar results were observed for drug addiction. Smokers with ADHD
had an estimated drug dependence rate of 43%, compared with 3% for
non-smokers without ADHD, 6% for non-smokers with ADHD and 11% for
smokers without ADHD.
The team then carried out a second analysis by
restricting the sample to those young people who did not show signs
of alcohol or drug misuse or dependence at the four-year
follow-up.
In this smaller group, they found that smokers
with ADHD had a significantly higher risk for drug dependence
compared to the other three groups. Smokers with ADHD had an
estimated drug dependence rate of 34%, compared to 8% for
non-smokers with ADHD, 10% for smokers without ADHD and 5% for
non-smokers without ADHD.
The reasons why cigarette smoking acts as a
gateway for drug and alcohol misuse is not entirely clear, but it
may be because nicotine affects the way dopamine (a mood-enhancing
chemical) is transmitted in the brain, which may in turn reinforce
other addictive behaviours.
Lead researcher Dr Joseph Biederman, of
Massachusetts General Hospital in Boston, said: "We found that
smoking greatly and significantly increased the risk of young
people with ADHD developing alcohol and drug misuse and dependence.
This has important public health implications, and suggests that if
smoking could be prevented in young people with ADHD then a large
amount of problems associated with alcohol and drugs could also be
prevented."
For further information, please
contact:
Liz Leicester
or Deborah Hart in the Communications
Department.
Telephone: 020 7235 2351 Extensions. 6298 or 6127
References:
Biederman J, Petty CR, Hammerness P, Batchelder H and Faraone SV. Cigarette smoking as a risk factor for other substance misuse: 10-year study of individuals with and without attention-deficit hyperactivity disorder. British Journal of Psychiatry, 2012, epub ahead of print publication bjp.bp.111.100339