Attention-deficit/hyperactivity disorder (ADHD) causes difficulties
in paying attention, keeping still, and suppressing impulsive behaviors.
It can lead to problems in school and on the job and create tensions
with family members and other people. In addition, research has shown
that children with ADHD have an elevated risk of becoming abusers of
drugs and alcohol. Studies that have tracked children to adulthood have
found higher rates of transition to abuse among those with ADHD compared
to those without the disorder. Conversely, studies with adult substance
abusers, particularly cocaine abusers, have found that when they were
children a high percentage had ADHD that was undiagnosed and therefore
NIDA-supported researchers have been trying to learn why ADHD
increases the risk of drug and alcohol abuse. Two possible explanations
have been suggested. First, the disorder itself may be responsible.
Alternatively, the medications used to treat the disorder may be to
ADHD is usually treated with behavioral therapy and prescription
stimulants, especially RitalinŽ (methylphenidate), DexedrineŽ, or
AdderallŽ. Such therapy frequently reduces symptoms, but some
clinicians have feared that giving prescription stimulants to children
may get them in the habit of taking stimulants, and, as a result, they
may be more likely to take illicit stimulants, such as cocaine and
methamphetamine. Another possibility is that the use of prescription
stimulants for treating ADHD may sensitize the brain to the rewarding
properties of stimulants, and, as a result, patients who use illicit
stimulants may be more likely to become addicted to them.
Some children treated for ADHD with stimulant medications experience
adverse effects, such as tics or loss of appetite. These children may be
treated instead with tricyclic antidepressants (TCAs), a class of
medications that includes imipramine, desipramine, and nortriptyline.
Just as with mild stimulants, some clinicians are concerned that giving
these mood-altering medications to children may get them in the habit of
taking drugs to feel better and so they may be more at risk of using
If ADHD treatment medications increase the risk of drug abuse, then
using them might do more harm than good over the course of the child's
lifetime. However, two new NIDA-supported studies suggest that treatment
medications may be part of the solution to drug abuse in ADHD, rather
than the problem.
One study found that children who were medicated for their ADHD were
less likely to become substance abusers during 4 years of followup than
were children with ADHD who were not medicated. The other study found
that administering an ADHD medication to adult cocaine abusers with the
disorder reduced their cocaine use.
Boys Treated for ADHD Abuse Drugs Less Than Untreated Boys
Researchers at Massachusetts General Hospital and the Harvard Medical
School, both in Boston, compared the incidence of substance abuse and
dependence in 56 boys with ADHD who were being treated with either
stimulants or TCAs at the beginning of the study, 19 boys with ADHD who
were not receiving any medications, and 137 boys without ADHD. All boys
were Caucasian and were followed for 4 years and then evaluated for
abuse of or dependence on marijuana, alcohol, hallucinogens, stimulants,
or cocaine. At the time of evaluation, the boys were at least 15 years
Treating ADHD with medications appeared to reduce the tendency to
abuse drugs and alcohol. While 75 percent of the unmedicated ADHD boys
had started abusing these substances in the previous 4 years, this was
true of only 25 percent of the medicated ADHD boys and 18 percent of the
boys without ADHD. The researchers calculated that treating ADHD with
medications reduced the risk of substance abuse or dependence by 84
Dr. Joseph Biederman, the principal investigator of the study, calls
this very important information for the field of pediatrics. "These
are the first data to refute the argument that ADHD medications increase
the risk that children will become addicts," he says. "There
have been studies consistent with these findings for many years, but now
we have solid statistical evidence that these medications decrease,
rather than increase, vulnerability to addiction, at least in adolescent
Why treatment with medications should reduce the incidence of
substance use disorders in boys with ADHD is not known, says Dr.
Biederman, just as what causes ADHD and how medications reduce ADHD
symptoms are also unknown. "I can only speculate that by reducing
ADHD symptoms, the medications allow the children to interact better
with their families and friends and to perform better in school,"
he says. "As a result, they are less likely to be ridiculed and
rejected by other children and to fail in school. Because of this, they
are less likely to be depressed and to take drugs in an attempt to treat
their depression." He says that another reason may be that the
medications reduce the tendency of ADHD children to be impulsive, which
often leads them to engage in risky activities, such as taking drugs.
Other researchers have reported that some adult cocaine abusers with
childhood histories of ADHD state that when they first started using
cocaine, the drug initially improved their ADHD symptoms. Their
concentration improved, they were less impulsive, and they felt calmer.
This would suggest that young people with ADHD who abuse cocaine and
other stimulants may be doing so to self-medicate their ADHD symptoms
rather than to treat depression resulting from rejection and failure.
"In some cases, young people with ADHD are not properly
diagnosed and treated, and, as a result, they have terrible
problems," says Dr. Arthur Horton of NIDA's Division of Treatment
Research and Development (DTRD). "Their lives are not going well,
so they try different things to make themselves feel better. They don't
know that RitalinŽ will alleviate their symptoms. If they happen to try
cocaine, they might find that it initially makes them more focused and
able to deal with life, so they keep taking it, and that's how they get
DTRD Director Dr. Frank Vocci points out that more research needs to
be done before definite conclusions can be drawn about the relationship
between ADHD therapy and substance abuse. "As it stands, this study
clearly supports the idea that medications protect individuals with ADHD
from becoming substance abusers during childhood and adolescence,"
he says. "However, whether or not they become substance abusers
when they reach adulthood is still an open question."
Dr. Biederman says that his group is continuing to collect data on
his sample as they age. Another followup study is currently under way on
the young men, who are now between 16 and 27 years old. This study
should help answer the question of whether ADHD medication therapy can
protect against substance abuse in late adolescence and early adulthood.
The researchers are also following a group of girls with ADHD and a
comparison group of girls without ADHD. A key question to be answered
will be whether gender differences exist in the effects of stimulants,
including the effects on substance abuse.
Treatment That Includes Methylphenidate Helps Adult Cocaine Abusers
In addition to helping protect children with ADHD from becoming
substance abusers, methylphenidate may also help adult cocaine abusers
with ADHD reduce their drug use. In a pilot study, Dr. Frances Levin and
researchers at Columbia University in New York City gave methylphenidate
for up to 12 weeks to 12 adult cocaine abusers with ADHD. Patients also
received individual weekly relapse prevention therapy, which involved
identifying situations in which they were likely to return to cocaine
use and developing strategies to avoid cocaine use in these situations.
Of the 12 patients who entered the study, 7 could be reached for a
3-month assessment. Patients reported a reduction in ADHD symptoms,
cocaine use, and craving; urine tests confirmed that their cocaine use
had in fact decreased significantly.
At present, Dr. Levin cannot say whether methylphenidate, the
behavioral therapy, or a combination of both was responsible for the
positive results. To answer this question and to determine whether these
preliminary results can be reproduced among other cocaine abusers with
ADHD, she is conducting a large clinical trial in which neither the
patients nor their therapists know whether the patients are receiving
methylphenidate or placebo.
Biederman, J., et al.
Pharmacotherapy of attention-deficit/hyperactivity disorder reduces risk
for substance use disorder. Pediatrics 104(2):e20, 1999 (www.pediatrics.org).
Gawin, F.; Riordan, C.;
and Kleber, H. Methylphenidate treatment of cocaine abusers without
attention deficit disorder: A negative report. American Journal of
Drug and Alcohol Abuse 11(3-4):193-197, 1985.
Levin, F.R., Evans, S.M.;
McDowell, D.M.; and Kleber, H.D. Methylphenidate treatment for cocaine
abusers with adult attention-deficit/hyperactivity disorder: A pilot
study. Journal of Clinical Psychiatry 59(6):300-305, 1998.
Levin, F.R., and Kleber,
H.D. Attention-deficit/hyperactivity disorder and substance abuse:
Relationships and implications for treatment. Harvard Review of
Psychiatry 2:246-258, 1995.