Studies Linking Ritalin and Depression Highlight Risk of Overdiagnosing ADHD
 

From Health Lover, Ilena Rosenthal
http://ilenarose.blogspot.com

Studies Linking Ritalin and Depression Highlight Risk of
Overdiagnosing ADHD

HEALTH JOURNAL
By TARA PARKER-POPE
January 25, 2005; Page D1

New research is raising questions about the long-term effects of
Ritalin and other drugs widely used to treat attention-deficit
hyperactivity disorder.

While most people agree that Ritalin and similar drugs can
dramatically improve the lives of kids suffering from ADHD, doctors
and parents have long been concerned about how the drugs might affect
a child's developing brain.

Now, new studies in rats suggest that methylphenidate, the generic
name for Ritalin, may permanently alter the brain and may lead to
depression in adulthood.

While the studies have limits -- a rat's brain is obviously very
different than a child's -- the research nonetheless highlights the
need to be sure of an ADHD diagnosis before putting a child on
medication. ADHD has been estimated to affect 3% to 12% of children
and is twice as common among boys as in girls.

But the criteria for the disorder -- such as whether a child is easily
distracted, doesn't seem to listen or can't sit still -- are highly
subjective and could easily describe many healthy children. Some
psychiatrists believe that as many as 15% of kids diagnosed with ADHD
actually suffer from some other problem that wouldn't be helped by
drugs -- such as a learning disability, a sleep disorder or even a
difficult relationship with a teacher.

Efforts are increasing to make ADHD diagnoses less subjective. Now,
"many kids are put on Ritalin when there's very weak evidence," says
Eric Nestler, chairman of the psychiatry department at the University
of Texas-Southwestern Medical Center in Dallas.

This latest research has particular significance for healthy children
who have been wrongly diagnosed and put on ADHD medication. In
December at the annual meeting of the American College of
Neuropsychopharmacology, researchers from Harvard Medical School's
McLean Hospital in Belmont, Mass., presented a study on depressive
symptoms that developed in adult rats exposed to Ritalin early in
life. Researchers at the University of Texas-Southwestern in Dallas
have reported similar findings.

While a rat study certainly can't be the final word on the risks or
benefits of any drug, the animals are a particularly valuable proxy to
monitor drug effects in a young brain, because for ethical reasons
it's difficult to study children.

In both rat studies, young rats were exposed daily to Ritalin or a
placebo, using doses that mimicked Ritalin use in childhood. The
treatment was stopped for a period of time, and adult rats were tested
for signs of depression and despair. The researchers found that rats
exposed to Ritalin were less interested in sugar water and sexual
activity than their counterparts who had never been given the drugs.

And in stressful situations, Ritalin rats gave up on tasks more
quickly. In a Harvard test, the rats were left to swim in a tank. The
Ritalin rats gave up and floated after about three minutes, nearly two
minutes sooner than other rats.

Notably, the rats were also exposed to cocaine. The Ritalin rats were
far less interested in the drug than other rats. That suggests kids
exposed to Ritalin probably aren't at higher risk for abusing drugs.
But it may also indicate that brain pathways involved in pleasure and
aversion, which can subsequently influence behavior, have been
changed, increasing the risk for depression.

The research measures only the impact of Ritalin on a healthy rat
brain. As a result, the studies are best extrapolated to healthy kids,
and emphasize the importance of getting the right diagnosis before
putting a child on Ritalin. While only Ritalin was studied, scientists
say it's reasonable that other stimulants used to treat ADHD, such as
Concerta or Adderall, would likely show similar effects.

"In defense of parents, they figure giving Ritalin is like giving
aspirin," says William Carlezon, a Harvard associate professor of
psychiatry and co-author of the most recent study. But "one of the
important implications of our work is that the effect of Ritalin
doesn't go away."

ADHD can be difficult to diagnose, and doctors rely on reports from
teachers and parents to determine how disruptive the problems really
are. But such methods are notoriously unreliable. In one recent McLean
study, data collected from 1,000 children showed some teachers never
rated any kids with ADHD while others singled out nearly all the boys
as potentially ADHD. "Teachers differ significantly in their
sensitivity and tolerance for certain behaviors," says Martin Teicher,
director of the Developmental Biopsychiatry Research Program at
McLean.

Dr. Teicher has developed the McLean Motion and Attention Test, or
M-Mat, which uses a computer to confirm an ADHD diagnosis. During the
15-minute test, the child completes a task on the computer while
wearing a headband with an infrared light. The light allows a video
camera to track his or her movements and fidgeting. A normal child
will fidget about 1,000 times, while a child with ADHD has been shown
to move three to four times more.

In children whom a doctor had previously diagnosed as having ADHD, the
computer agrees about 85% of the time. Dr. Teicher notes that the test
isn't a substitute for the opinions of teachers, parents and doctors
in diagnosing behavioral problems, but that it can be useful for
helping to ferret out the estimated 15% of cases in which a learning
disability or other problem has been mistaken for ADHD. It can also
help confirm whether a drug like Ritalin is working.

McLean researchers are working with a private firm to expand use of
the test, which is now used in about 60 hospitals around the country.
For a list of hospitals who offer the M-Mat, go to
http://www.mclean.harvard.edu/resear...lunit/dbrp.php.