NIH Research Suggests Stimulant Treatment for
ADHD Does Not Contribute to Substance Abuse Later in Life
Early Evaluation for Substance Abuse Still Important for This
High Risk Group
Treating children as early as age six or seven with stimulants
for Attention Deficit Hyperactivity Disorder (ADHD) is not likely
to increase risk of substance abuse as adults, according to two
studies funded by the National Institutes of Health (NIH). However,
the studies also showed treatment with stimulants did not prevent
substance abuse later in adulthood. The studies, conducted by researchers
at New York University School of Medicine (NYU) and the Massachusetts
General Hospital/Harvard Medical School (Mass General) are being
published in this month’s American Journal of Psychiatry.
"There has been widespread debate on the possible link between
stimulant medications for children and adolescents with ADHD and
substance abuse later in life," said NIH Director Elias Zerhouni. "Researchers
supported by several NIH institutes are working to resolve this
issue so we can offer scientifically valid information to clinicians
and parents concerned about the treatment of their children with
stimulant medications."
The NYU study evaluated substance abuse behaviors in 176 young
men who had been treated for ADHD when they were children to determine
whether there was a relationship between the age when stimulant
treatment was initiated and subsequent drug abuse in adulthood.
They found that those children who began treatment when they were
younger (6-7 years old) had substance abuse rates no different
than from a comparison group who did not have ADHD (27 percent
vs 29 percent); however those who began treatment when they were
older (8-12 years old) had higher rates of substance abuse (44
percent), which was accounted for by co-occurring antisocial personality
disorder. "Overall, our results suggest that early stimulant
treatment does not appear to have negative outcomes for substance
abuse in children with ADHD," said Salvatore Mannuzza, Ph.D.,
M.Ph., lead author of the study.
The Mass General researchers, led by researcher Joseph Biederman,
M.D., conducted a ten-year follow-up study of boys with ADHD, now
grown up. They also found no evidence that prior treatment with
stimulants affected the rate of substance use disorders for alcohol,
drugs, or nicotine.
"Because the use of stimulants in children did not decrease
the risk of later substance abuse, it is still critical that young
people with ADHD be screened for substance abuse," said NIDA
Director Nora Volkow. "Further, treatment approaches need
to go beyond standard ADHD strategies towards integrated treatments
that target both ADHD and substance abuse as soon as symptoms emerge."
Researchers point out both studies had limitations, including
small samples, non-randomized study designs, and an exclusively
male population that was not racially balanced.
"Prospective studies are also needed on a larger sample of
adolescents treated with stimulant medications to more carefully
evaluate the consequences of stimulant exposure, since this is
a period of particular vulnerability for drug abuse and dependence," added
Volkow.
There are at least two reasons for concern about drug abuse in
children treated with stimulants for ADHD. First — stimulants
are widely prescribed and like drugs of abuse, they increase dopamine
concentrations in the brain, and can themselves be abused. In addition,
studies have shown that the earlier an individual is exposed to
some substances with abuse potential, the greater the risk of substance
abuse as an adult. However, there is also evidence of impaired
dopamine activity in the brains of individuals with ADHD, which
could explain both their high risk for drug abuse, and why stimulant
drugs in this population can relieve ADHD symptoms without the
added risk for later substance abuse. In other words, the risk
of substance abuse in patients with ADHD most likely has nothing
to do with the use of stimulant medications; however, more research
is needed.
The NYU study was funded by the National Institute on Drug Abuse
(NIDA) and the National Institute of Mental Health; the Mass General
study was funded by the National Institute of Child Health and
Human Development and NIDA.
Attention Deficit Hyperactivity Disorder is the most commonly
diagnosed behavioral disorder in children and adolescents in the
United States. It is estimated that between three and five percent
of children have ADHD, or at least two million children in the
United States. The median age of onset of ADHD is seven years,
although the disorder can persist into adolescence and occasionally
into adulthood. The principal characteristics of ADHD are inattention,
hyperactivity, and impulsivity. Because many normal children have
these behaviors, but at a level appropriate to their stage of development,
it is important that any child suspected of having ADHD receive
a thorough examination. Also, because symptoms may be caused by
another disorder, appropriate diagnosis by a well-qualified professional
is essential. Methylphenidate and amphetamine are the most commonly
used stimulant medications to treat ADHD.
More information on ADHD can be found on the Web site of the National
Institute on Mental Health at http://www.nimh.nih.gov/health/publications/the-numbers-count-mental-disorders-in-america.shtml#ADHD.
The National Institute on Drug Abuse is a component of the National
Institutes of Health, U.S. Department of Health and Human Services.
NIDA supports most of the world's research on the health aspects
of drug abuse and addiction. The Institute carries out a large
variety of programs to ensure the rapid dissemination of research
information to inform policy and improve practice. Fact sheets
on the health effects of drugs of abuse and further information
on NIDA research can be found on the NIDA web site at http://www.drugabuse.gov.
The National Institute of Mental Health (NIMH) mission is to reduce
the burden of mental and behavioral disorders through research
on mind, brain, and behavior. More information is available at
the NIMH website at www.nimh.nih.gov.
The NICHD sponsors research on development, before and after birth;
maternal, child, and family health; reproductive biology and population
issues; and medical rehabilitation. For more information, visit
the Institute’s Web site at www.nichd.nih.gov.
The National Institutes of Health (NIH) — The Nation's
Medical Research Agency — includes 27 Institutes and
Centers and is a component of the U.S. Department of Health and
Human Services. It is the primary federal agency for conducting
and supporting basic, clinical and translational medical research,
and it investigates the causes, treatments, and cures for both
common and rare diseases. For more information about NIH and
its programs, visit www.nih.gov.
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