ADHD - you can see it in the eyes

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ADHD - you can see it in the eyes

http://www.smh.com.au/news/Health/ADHD--you-can-see-it-in-the-eyes/2005/01/17/11\

05810845640.html

Scientists have developed a simple eye test that can diagnose

hyperactive children.

Attention deficit hyperactivity disorder (ADHD) affects up to 7percent

of school-age children in Britain and the condition can prove hard to

diagnose.

Researchers from Brunel University in west London have come up with a

10-minute test to identify children likely to need special attention

because of ADHD.

The Pavlidis test involves children looking at a spot of light on a

computer screen and following it with their eyes as it moves in

different patterns.

Until now diagnosis of the disorder has been achieved through subjective

questionnaires. The Brunel team believes it has found the world's first

objective and biological test for the condition.

Pavlidis and Panagiotis Samaras, from the university's school of

sport and education, looked at whether there was a significant link

between the eye movements of children aged four to six and the symptoms

of the disorder.

The researchers found significant differences in the eye movement of

children with the disorder and children without it. The ADHD group had

much more erratic patterns of eye movement.

The computerised test correctly identified 93 per cent of children as

either having the disorder or normal.

" This biological test proved to be objective, and highly accurate, and

can be used at pre-school age, " Professor Pavlidis said. " The discovery

is also important internationally as the test operates equally

effectively regardless of language, race, culture and IQ. "

Professor Pavlidis said early diagnosis of ADHD would allow children to

receive proper treatment that would reduce learning, behavioural and

secondary psychological problems.

Children with the disorder are often treated with medication, such as

Ritalin, to control their symptoms. The drugs can help them lead a more

normal life, but can also have side effects.

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A recent news release described Harvard researchers' findings: drugs

like and including Ritalin induce depresssion-like traits and

learned helplessness (A-.

A. Attention Deficit Drugs May Have Long-Term Effects

http://www.abcnews.go.com/wire/US/reuters20031208_12.html

Dec. 8 -- WASHINGTON (Reuters) - Drugs given to children to treat

attention deficit hyperactivity disorder could have long-term effects

on their growing brains, studies on rats suggest.

Several studies published on Monday show that rats given a popular

ADHD drug were less likely to want to use cocaine later in life, but

also often acted clinically depressed and behaved differently from

rats give dummy injections.

While rats are different from humans, the studies suggest that

doctors should watch children for long-term effects, too.

In the United States between 3 percent and 5 percent of children are

diagnosed with attention deficit disorder, marked by reduced ability

to concentrate, difficulty in organizing and impulsive behavior.

Patients are commonly prescribed stimulants but the practice is

sometimes controversial.

Carlezon of McLean Hospital and Harvard Medical School in

Boston and colleagues raised two groups of rats. One was given

Ritalin, known generically as methylphenidate, during the rat

equivalent of pre-adolescence, while the other was given a salt water

injection.

When they matured, the rats were tested for " learned helplessness " --

how quickly they gave up on behavioral tasks under stress.

" Rats exposed to Ritalin as juveniles showed large increases in

learned-helplessness behavior during adulthood, suggesting a tendency

toward depression, " Carlezon said in a statement.

But rats, which generally like cocaine, were less likely to eat it if

they had been give Ritalin.

Carlezon said he did not believe the effects were specific to

Ritalin, made by Swiss drug giant Novartis. It could instead be a

general effect of stimulant drugs, many of which act by increasing

the activity of a key message-carrying chemical called dopamine.

Higher dopamine levels could affect the way brain cells cement their

connections during development, Carlezon wrote in the Dec. 15 issue

of the journal Biological Psychiatry.

A team at the University of Texas Southwestern Medical Center at

Dallas found that adult rats were less responsive to rewarding

stimuli and reacted more to stress if they had been given

methylphenidate as youngsters.

A third study done by a team at Finch University of Health

Sciences/The Chicago Medical School found changes in how dopamine

neurons responded to methylphenidate.

" These three studies remind us how limited our knowledge is of the

neurochemical and functional characteristics of the human brain

during childhood and adolescence and on the effects of psychotropic

drugs on brain development, " Dr. Insel, Director of the

National Institute of Mental Health, wrote in a commentary.

B. Biol Psychiatry. 2003 Dec 15;54(12):1330-7.

Enduring behavioral effects of early exposure to methylphenidate in rats.

Carlezon WA Jr, Mague SD, Andersen SL.

Department of Psychiatry, Harvard Medical School, McLean Hospital, Belmont,

Massachusetts 02478, USA.

BACKGROUND: Methylphenidate (MPH) is a stimulant prescribed for the

treatment of

attention-deficit/hyperactivity disorder (ADHD). Stimulant drugs can cause

enduring behavioral adaptations, including altered drug sensitivity, in

laboratory animals. We examined how early developmental exposure to

stimulants

affects behavior in several rodent models. METHODS: Rats received MPH or

cocaine

during preadolescence (P20-35). Behavioral studies began during

adulthood (P60).

We compared how early exposure to MPH and cocaine affects sensitivity to

the

rewarding and aversive properties of cocaine using place conditioning.

We also

examined the effects of early exposure to MPH on depressive-like signs

using the

forced swim test, and habituation of spontaneous locomotion, within

activity

chambers. RESULTS: In place-conditioning tests, early exposure to MPH or

cocaine

each made moderate doses of cocaine aversive and high doses less rewarding.

Early MPH exposure also caused depressive-like effects in the forced

swim test,

and it attenuated habituation to the activity chambers.CONCLUSIONS: Early

exposure to MPH causes behavioral changes in rats that endure into

adulthood.

Some changes (reduced sensitivity to cocaine reward) may be beneficial,

whereas

others (increases in depressive-like signs, reduced habituation) may be

detrimental...

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