Number of Childhood Symptoms of ADHD Strongly Linked to Adult Risk of Smoking
DURHAM, N.C. -- The greater the number of reported symptoms
of attention-deficit hyperactivity disorder (ADHD) shown in
childhood, the greater the risk a person is of becoming a
regular smoker, according to researchers at Duke University
The research team cautions that their findings do not mean
that a diagnosis of ADHD as a child leads a person to become a
smoker, and they emphasized that their study only looked at
self-reported symptoms of ADHD and not at a clinical diagnosis.
However, the findings make it all the more important that
children who exhibit a high number of ADHD symptoms receive
additional or specialized education about the hazards of
smoking, they said.
ADHD is a common psychiatric disorder that affects
approximately five percent of school aged children and is
characterized by difficulty paying attention, hyperactivity and
impulsivity. In order to meet the criteria for having ADHD, a
person must exhibit a certain number of symptoms in multiple
settings and be impaired as a result of these symptoms.
"We wanted to know why people with ADHD smoke more often
than those who don't have ADHD," said Scott H. Kollins, Ph.D.,
assistant professor of psychiatry at Duke and lead author on
the study. "It may be something about the symptoms themselves
that cause people to smoke, but we aren't certain of that. What
our data clearly show is that for every symptom of ADHD
reported in childhood, the stronger the likelihood that person
would smoke regularly during adolescence or early adulthood.
This relationship held true even for individuals reporting
fewer than the number of symptoms we see in people with a
diagnosis of ADHD."
The research team sought to determine whether ADHD symptoms
increased the lifetime risk for regular smoking, regardless of
current smoking status. To determine the ADHD-smoking link, the
team used a database of information gathered from thousands of
young adults surveyed as part of the National
Longitudinal Study of Adolescent Health, a nationally
representative sample of adolescents. The researchers used data
on 13,852 adolescents in the survey for whom complete survey
data were available on ADHD symptoms and tobacco use. The
survey participants were asked to rate their frequency of a
range of ADHD symptoms of inattentiveness and impulsivity, as
well as reporting their smoking status.
"We have established a strong association between ADHD
symptoms and smoking," Kollins said of the researchers'
analysis of the data. "Specifically, we found a strong
relationship between the age of onset of smoking and the number
of reported symptoms of ADHD in childhood. Smokers who reported
the most inattentive or hyperactive-impulsive symptoms as
children started smoking, on average, a year earlier than those
reporting the fewest numbers of symptoms. This extra year of
smoking is very important from a public health
Among current smokers in the sample, more ADHD symptoms were
also associated with higher consumption of cigarettes per
"The results were surprising because we learned that the
smoking risks aren't necessarily related to having ADHD itself,
but rather for each symptom of ADHD that you have, the greater
your chances of becoming a smoker," said Joseph McClernon,
Ph.D., assistant research professor of psychiatry at Duke and
an author on the study. "We need to figure out why this
relationship is there. We want to understand the mechanisms
that underlie what we've found and see if that information can
be used to prevent smoking or help more people quit."
Additional research is needed to more precisely determine
the nature of the relationship between the symptoms of ADHD and
smoking risk. The investigators said, for example, they would
like to determine whether specific symptoms or clusters of
symptoms are more strongly associated with the risk of becoming
a regular smoker.
The team is already examining the differences between adult
smokers with and without ADHD in smoking cessation programs.
The researchers are particularly interested in learning whether
those with ADHD have a harder time quitting and if their
withdrawal symptoms are any worse.
"We think people with ADHD may benefit in some way from
either more intensive cessation programs or modified programs
that are more in tune with their needs, McClernon added. "They
may require treatments we haven't imagined yet."
The researchers point out there may be problems with
presenting smoking prevention programs to children with
symptoms of ADHD. They are concerned that a certain percentage
of young students who need the information the most aren't
going to really "get it" because of their inability to pay
close attention during presentations or classes.
"We may need to get more creative in how we think about
talking to kids about smoking," added McClernon. "If your kids
show signs of ADHD, it's probably a good idea to be even more
proactive about talking with them about smoking and not
starting in the first place."
Bernard Fuemmeler, Ph.D., of the National Cancer Institute,
is also an author on the study.