Featured Research

from universities, journals, and other organizations

ADHD Appears To Be Associated With Depressed Dopamine Activity In The Brain

Date:
August 8, 2007
Source:
JAMA and Archives Journals
Summary:
Adults with attention-deficit/hyperactivity disorder show a blunted response to the drug methylphenidate (Ritalin), which increases brain dopamine levels, according to a new report. This suggests that dopamine dysfunction may be involved with ADHD symptoms, and may contribute to substance abuse that often occurs simultaneously.

Adults with attention-deficit/hyperactivity disorder (ADHD) show a blunted response to the drug methylphenidate (Ritalin), which increases brain dopamine levels, according to a report in the August issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

Related Articles


This suggests that dopamine dysfunction may be involved with ADHD symptoms and may contribute to substance abuse that often occurs simultaneously.

ADHD is the most prevalent psychiatric disorder among children, according to background information in the article. "Despite decades of research, the specific neurobiological mechanisms underlying this disorder still remain unclear," the authors write. "Genetic, clinical and imaging studies point to a disruption of the brain dopamine system, which is corroborated by the clinical effectiveness of stimulant drugs (methylphenidate hydrochloride and amphetamine), which increase extracellular dopamine in the brain."

Nora D. Volkow, M.D., of the National Institute on Drug Abuse, Bethesda, Md., and colleagues studied 19 adults with ADHD (average age 32) who had never received medication and 24 healthy controls (average age 30). Brain scans were performed using positron emission tomography (PET) and a drug known as raclopride labeled with carbon 11 ([11C]raclopride), which binds with dopamine receptors.

Scans were performed twice, after injections of placebo and of methylphenidate; the participants did not know which drug they had received. Participants also were asked to report the severity of their ADHD symptoms, whether they could detect the drug, if they liked or disliked it, and if it made them feel "high," tired, alert, anxious or restless.

In individuals with ADHD, methylphenidate caused less of a decrease in the amount of [11C]raclopride that bound to dopamine receptors in areas of the brain associated with attention than it did in those without ADHD. Since levels of methylphenidate in the blood were the same in both groups, this suggests that those with ADHD released less dopamine in response to the drug than controls. This blunted response was associated with symptoms of inattention. Exploratory analyses also found evidence of reduced [11C]raclopride binding in the hippocampus and amygdala in those with ADHD. These areas of the brain are part of the limbic system, involved in emotional responses as well as consolidating and retrieving memories.

"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 authors write.

Individuals with ADHD also reported liking methylphenidate more than individuals without ADHD, the authors note. "The reinforcing responses to methylphenidate were negatively correlated with the dopamine increases, suggesting that decreased dopaminergic activity may also be involved in modulating the magnitude of the reinforcing effects of methylphenidate," they continue. "This suggests that dopamine dysfunction is involved with symptoms of inattention but may also contribute to substance abuse comorbidity in ADHD."

Reference: Arch Gen Psychiatry. 2007;64(8):932-940.


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Cite This Page:

JAMA and Archives Journals. "ADHD Appears To Be Associated With Depressed Dopamine Activity In The Brain." ScienceDaily. ScienceDaily, 8 August 2007. <www.sciencedaily.com/releases/2007/08/070806164505.htm>.
JAMA and Archives Journals. (2007, August 8). ADHD Appears To Be Associated With Depressed Dopamine Activity In The Brain. ScienceDaily. Retrieved March 31, 2015 from www.sciencedaily.com/releases/2007/08/070806164505.htm
JAMA and Archives Journals. "ADHD Appears To Be Associated With Depressed Dopamine Activity In The Brain." ScienceDaily. www.sciencedaily.com/releases/2007/08/070806164505.htm (accessed March 31, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Tuesday, March 31, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
S. Leone in New Anti-Ebola Lockdown

S. Leone in New Anti-Ebola Lockdown

AFP (Mar. 28, 2015) — Sierra Leone imposed a three-day nationwide lockdown Friday for the second time in six months in a bid to prevent a resurgence of the deadly Ebola virus. Duration: 01:17 Video provided by AFP
Powered by NewsLook.com
These Popular Antibiotics Can Cause Permanent Nerve Damage

These Popular Antibiotics Can Cause Permanent Nerve Damage

Newsy (Mar. 27, 2015) — A popular class of antibiotic can leave patients in severe pain and even result in permanent nerve damage. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins