Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

ADD & ADHD Health Center

Font Size

ADHD Gene Discovered

Attention Deficit More Common in Kids with 'Snap-25' Mutation
WebMD Health News


Sept. 24, 2002 -- A gene missing in hyperactive mice may explain some human cases of ADHD.

ADHD -- attention deficit/hyperactivity disorder -- runs in families. It's more common in boys than in girls. If one twin has ADHD, the other is very likely to have it, too. These facts make scientists think that the tendency to get ADHD is inherited. So far, the search for an ADHD gene has turned up many clues, but no smoking gun.

One of these clues came in 1996, when researchers found that a strain of hyperactive mice lacked a gene called SNAP-25. When genetic engineers put the gene back into these mice, they weren't hyperactive any more.

Now an Irish research team finds that humans with a certain variation of their SNAP-25 gene are 50% more likely than those without the variation to be hyperactive. The researchers did genetic tests on 93 families in which at least two members had ADHD. Not everyone who had the SNAP-25 variation had ADHD. Not everyone with ADHD had a variation in their SNAP-25 gene. But carrying the variant gene increased the chance of having ADHD, especially when the gene was inherited from the father.

The research team, led by Michael Gill, MD, PhD, of Trinity College, Dublin, concludes that ADHD is the result of many things acting together. They note that because there were relatively few people in their study, the link between SNAP-25 and ADHD must be confirmed in other studies.

The study appears in the September issue of Molecular Psychiatry.

Today on WebMD

Post it notes
Symptoms and treatments.
Close up of eye
What's zapping your focus?
man driving car
How to manage your impulses.
contemplating woman
Learn to stop procrastinating.
concentration killers
Woman taking a vitamin or supplement
ADHD and Substance Abuse
Reduce Side Effects ADHD Medications

boy eating egg
smiling man
ADHD in Marriage and Romantic Relationships
Adult man lying awake in bed