Navigation Links
Study says lead may be the culprit in ADHD

ADHD, or attention-deficit/hyperactivity disorder, is among the costliest of behavioral disorders. Its combination of inattention, impulsivity and hyperactivity leads to accidental injuries, school failure, substance abuse, antisocial behavior and more. Yet despite nearly a century of study, the disorder's roots remain mysterious.

Much of modern ADHD research has focused on heritability of the condition, and indeed evidence suggests that genes may account for as much as 70 percent of hyperactivity and inattention in children. But that leaves 30 percent unexplained, so recently the focus has shifted to the environment. What is it that triggers an underlying susceptibility and changes it into a full-blown disorder? New research suggests that the culprit may be an old villainleadand what's more it explains the causal pathway from exposure to disability.

Lead is a neurotoxin. This has been known for a long time, and in fact government regulation drastically reduced environmental lead a generation ago. But regulating automobile fuel and paint didn't entirely eliminate lead from the environment. It's found in trace amounts in everything from children's costume jewelry to imported candies to soil and drinking water. Every American today is exposed to low levels of the metal, and indeed nearly all children have measureable levels of lead in their bodies. According to psychological scientist Joel Nigg of the Oregon Health & Science University, this universal low-level exposure makes lead an ideal candidate for the disorder's trigger.

This was just a theory until quite recently, but two recent studies now provide strong evidence. The first study compared children formally diagnosed with ADHD to controls, and found that the children with the disorder had slightly higher levels of lead in their blood. This study showed a link only between blood lead and hyperactivity/impulsivity symptoms, not inattention. But a second study showed a robust link between blood lead and both parent and teacher ratings of ADHD symptoms, including both hyperactivity and attention problems. In both studies, the connection was independent of IQ, family income, race, or maternal smoking during pregnancy.

Nigg offers a causal model for the disabling symptoms associated with ADHD: Lead attaches to sites in the brain's striatum and frontal cortex, where it acts on the genes in these regionscausing them to turn on or remain inactive. Gene activity shapes the development and activity of these brain regions. By disrupting brain activity, the toxin in turn alters psychological processes supported by these neurons, notably cognitive control. Finally, diminished cognitive control contributes to hyperactivity and lack of vigilance. Nigg describes his new data and his explanatory model in the February issue of the journal Current Directions in Psychological Science.


Contact: Catherine Allen-West
Association for Psychological Science

Related medicine news :

1. Penn study finds pro-death proteins required to regulate healthy immune function
2. New study shows promise in reducing surgical risks associated with surgical bleeding
3. Study, meta-analysis examine factors associated with death from heatstroke
4. Study suggests loss of 2 types of neurons -- not just 1 -- triggers Parkinsons symptoms
5. Study says COPD testing is not measuring up
6. Preclinical study suggests organ-transplant drug may aid in lupus fight
7. Ability to cope with stress can increase good cholesterol in older white men, study finds
8. High alcohol consumption increases stroke risk, Tulane study says
9. Mailman School of Public Health study examines link between racial discrimination and substance use
10. Pitt study finds inequality in tobacco advertising
11. Stanford study highlights cost-effective method of lowering heart disease risks
Post Your Comments:
(Date:11/26/2015)... ... November 26, 2015 , ... Patients at Serenity Point ... come together on Thanksgiving Day to share the things that they are most ... Serenity Point YouTube channel, patients displayed what they wrote on index cards, describing ...
(Date:11/26/2015)... ON (PRWEB) , ... November 26, 2015 , ... ... of a real-time eReferral system for diagnostic imaging in the Waterloo region. Using ... BMD and Nuclear Medicine tests directly from their electronic medical record (EMR) without ...
(Date:11/26/2015)... ... 26, 2015 , ... The Catalent Applied Drug Delivery Institute ... integrate dose form selection in early phase drug development. The first of these ... bringing together the UK’s emerging life sciences companies, corporate partners, and investors, at ...
(Date:11/26/2015)... ... 2015 , ... PRMA Plastic Surgery is updating their record books yet again ... free flap breast reconstruction surgery! , “What an accomplishment for the PRMA team, says ... and it’s an honor to have served all of these women.” , PRMA is ...
(Date:11/26/2015)... Aliso Viejo, CA (PRWEB) , ... November 26, ... ... X users a new set of retro-fused, self-animating trailer titles with ProTrailer: Vintage. ... custom style options. These classically-influenced trailer titles work with any font, giving users ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... 2015 --> ... blends immunotherapy with Bremachlorin-photodynamic therapy for advanced cancer. ... immunotherapy with Bremachlorin-photodynamic therapy for advanced cancer.   ... immunotherapy with Bremachlorin-photodynamic therapy for advanced cancer.   ... that immunotherapy can be efficiently combined with photodynamic therapy ...
(Date:11/26/2015)... 26, 2015 --> ... SyMRI to find optimal contrast weighting of MRI for ... has signed a research agreement with SyntheticMR in order to ... SyMRI, it is possible to generate multiple contrast images from ... patient has left, thus making it possible to both fine ...
(Date:11/26/2015)... FRANCISCO , November 26, 2015 ... billion by 2022, according to a new report by Grand ... Chronic Kidney Disease (CKD) which demands kidney transplantation is expected ... and cost effective substitute for organ transplantation. --> ... billion by 2022, according to a new report by Grand ...
Breaking Medicine Technology: