Adult ADHD linked with dopamine levels

Aug 09, 2007

Adults with attention-deficit/hyperactivity disorder have a reduced response to the drug Ritalin, U.S. government scientists have found.

Ritalin -- methylphenidate -- increases brain dopamine levels, helping ADHD patients, the scientists noted, which suggests people with ADHD suffer from a dysfunction in the dopamine system.

Dr. Nora Volkow of the National Institute on Drug Abuse and colleagues studied 19 adults with ADHD who had never received medication, and 24 healthy controls.

Positron emission tomography brain scans were performed after blind injections of a drug that inactivates dopamine receptors. Scans were performed after injections of placebo and of Ritalin.

People with ADHD released less dopamine than controls did in response to the drug. The blunted response was associated with symptoms of inattention.

"The findings of reduced dopamine release in subjects with ADHD are consistent with the notion that the ability of stimulant medications to enhance extracellular dopamine underlies their therapeutic effects in ADHD," the researchers said.

The findings appear in the August issue of Archives of General Psychiatry.

Copyright 2007 by United Press International

Explore further: West Africa seals off Ebola outbreak epicentre

add to favorites email to friend print save as pdf

Related Stories

Huge waves measured for first time in Arctic Ocean

8 hours ago

As the climate warms and sea ice retreats, the North is changing. An ice-covered expanse now has a season of increasingly open water which is predicted to extend across the whole Arctic Ocean before the middle ...

Underwater elephants

8 hours ago

In the high-tech world of science, researchers sometimes need to get back to basics. UC Santa Barbara's Douglas McCauley did just that to study the impacts of the bumphead parrotfish (Bolbometopon muricatum) on cor ...

Recommended for you

West Africa seals off Ebola outbreak epicentre

2 hours ago

West Africa's Ebola-hit nations announced a cross-border isolation zone on Friday, sealing off the epicentre of the world's worst-ever outbreak as health chiefs warned the epidemic was spiralling out of control.

STDs on the rise in Miami area

6 hours ago

Rates of both chlamydia and syphilis in Miami-Dade have nearly doubled since 2006, according to new statistics from the Florida Department of Health.

User comments : 0