Common pesticide may increase risk of ADHD

Mice exposed to a commonly used pesticide in utero and through lactation exhibited several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behaviour.

A commonly used pesticide may alter the development of the brain's dopamine system, responsible for emotional expression and cognitive function, and increase the risk of attention deficit hyperactivity disorder in children, according to a new Rutgers study.

The research published Wednesday in the Journal of the Federation of American Societies for Experimental Biology (FASEB J.), by Rutgers scientists and colleagues from Emory University, the University of Rochester Medical Center, and Wake Forest University discovered that mice exposed to the pyrethroid pesticide deltamethrin in utero and through lactation exhibited several features of ADHD, including dysfunctional dopamine signaling in the brain, hyperactivity, working memory, attention deficits and impulsive-like behaviour.

Attention deficit hyperactivity disorder most often affects children, with an estimated 11 percent of children between the ages of 4-17, about 6.4 million, diagnosed as of 2011.

Boys are three to four times more likely to be diagnosed than girls. While early symptoms, including an inability to sit still, pay attention and follow directions, begin between the ages of 3 to 6, diagnosis is usually made after the child starts attending school full time.

Importantly, in this study, the male mice were affected more than the female mice, similar to what is observed in children with ADHD.

The ADHD-like behaviours persisted in the mice through adulthood, even though the pesticide, considered to be less toxic and used on golf courses, in the home, and on gardens, lawns and vegetable crops, was no longer detected in their system.

Although there is strong scientific evidence that genetics plays a role in susceptibility to the disorder, no specific gene has been found that causes ADHD and scientists believe that environmental factors may also contribute to the development of the behavioural condition.

Using data from the Centers for Disease Control, National Health and Nutrition Examination Survey (NHANES) the study analyzed health care questionnaires and urine samples of 2,123 children and adolescents.

Researchers asked parents whether a physician had ever diagnosed their child with ADHD and cross-referenced each child's prescription drug history to determine if any of the most common ADHD medications had been prescribed.

Children with higher pyrethroid pesticide metabolite levels in their urine were more than twice as likely to be diagnosed with ADHD.

These findings provide strong evidence, using data from animal models and humans, that exposure to pyrethroid pesticides, including deltamethrin, may be a risk factor for ADHD, says lead author Jason Richardson, associate professor in the Department and Environmental and Occupational Medicine at Rutgers Robert Wood Johnson Medical School and a member of the Environmental and Occupational Health Sciences Institute (EOHSI).

"Although we can't change genetic susceptibility to ADHD, there may be modifiable environmental factors, including exposures to pesticides that we should be examining in more detail," says Richardson.

Young children and pregnant women may be more susceptible to pesticide exposure because their bodies do not metabolize the chemicals as quickly.

This is why, Richardson says, human studies need to be conducted to determine how exposure affects the developing fetus and young children.

"We need to make sure these pesticides are being used correctly and not unduly expose those who may be at a higher risk," Richardson says.

More information: "Developmental pesticide exposure reproduces features of attention deficit hyperactivity disorder." FASEB J fj.14-260901; published ahead of print January 28, 2015, doi: 10.1096/fj.14-260901

ADHD: Language problems common in children with ADHD

Children who have attention-deficit/hyperactivity disorder are nearly three times more likely to have language problems than kids without ADHD, according to new research.

And those language difficulties can have far-reaching academic consequences, the study found.

The study, published online April 21 in Pediatrics, looked at 6- to 8-year-olds with and without ADHD in Australia.

"We found that 40 percent of children in the ADHD group had language problems, compared to 17 percent of children in the 'control' group," said Emma Sciberras, a clinical psychologist and post-doctoral research fellow at the Murdoch Children's Research Institute in Victoria, Australia.

"Rates of language problems were similar in boys and girls with ADHD," she added.

Emma Sciberras

Children with ADHD commonly have trouble with school performance and social functioning.

The impact that language problems might have on these factors hasn't been well-studied, the study authors noted.

"The differences in academic functioning between children with ADHD and language problems, compared to those with ADHD alone, were quite large and clinically meaningful," said Sciberras.

Language problems refer to spoken language—both receptive and expressive language. Receptive language is the ability to listen and understand what's being said; expressive is the ability to speak and be understood.

In a separate study in the same issue of the journal, Sciberras and her colleagues looked at almost 400 children with ADHD, aged 5 to 13, and found almost two-thirds had one or more anxiety disorders.

When children with ADHD had two or more anxiety disorders—this was true for one-third of the kids—their quality of life, behavior and daily functioning suffered, the researchers said.

"It is very common for children with ADHD to experience additional difficulties," said Sciberras. "Both of these studies demonstrate that the additional difficulties that go along with ADHD, in this case anxiety and language problems, can make daily functioning even harder for children with ADHD."

The language study included 179 children diagnosed with ADHD and 212 without the attention disorder. Fewer than half of the children with ADHD were taking medications to help control their symptoms.

After adjusting for sociodemographic factors and other conditions, such as autism spectrum disorders, the researchers found that the risk of language problems was 2.8 times higher in children with ADHD.

When the researchers looked at how those language problems affected school work, they found lower math, reading and academic scores.

However, the researchers didn't find that language problems had an impact on social functioning.

"We were surprised that language problems were not associated with poorer social functioning for children with ADHD," Sciberras said.

"It could be that children with ADHD are already experiencing poorer social functioning due to other factors including their ADHD symptoms or other associated difficulties."

However, Sciberras cautioned that language troubles might become more problematic as these kids get older because social relationships get more complex with age.

One outside expert said the study is a good reminder for parents and physicians.

Bradley Berg

"If a child has ADHD and they're struggling in school, even though their ADHD symptoms are well-controlled, in addition to getting tested for learning disabilities, they should also be looked at for language difficulties as well. And that's not something we always think of," said Dr. Bradley Berg, medical director of McLane Children's Pediatrics at Baylor Scott & White Healthcare in Round Rock, Texas.

Whether speech-language interventions will help the youngsters with ADHD isn't clear, however.

Berg also pointed out that this issue is a "chicken-and-egg" problem.

He said "We don't know if these kids have;

• a language disorder that's causing them to not understand what's going on at school 
• and that's making them restless and fidgety because they're bored
• Or do they have ADHD and that's causing difficulty understanding the language. 
• Or is there something going on in an area of the brain that creates both of these problems?

It's possible that the findings from this Australian study might not translate to a U.S. population.

For one thing, medication trends might differ, Berg said. For children with ADHD who also suffer anxiety, Sciberras said medications might help, and a type of psychotherapy called cognitive behavioral therapy could also be useful.

The researchers are currently conducting a study to treat anxiety in children with ADHD.

"If parents are concerned that their child with ADHD has anxiety, language or any other additional difficulties that are not currently being managed, we encourage them to discuss their concerns with their child's treating clinician," she said.

Psychotropic drugs commonly prescribed to children with ASD

Psychotropic medications, singly and in combination, are commonly prescribed for children with autism spectrum disorders (ASD), according to research published online Oct. 21 in Pediatrics.

Donna Spencer, Ph.D., of OptumInsight in Eden Prairie, Minn., and colleagues reviewed claims data from 2001 to 2009 for 33,565 children with ASD to assess rates and predictors of psychotropic use.

The researchers found that 64 percent of children with ASD had filled a prescription for at least one psychotropic medication.

Polypharmacy was evident, with concurrent medication fills across at least two drug classes in 35 percent and across at least three classes in 15 percent.

Factors associated with greater risk of psychotropic use and multiclass polypharmacy included older age; psychiatrist visit; and evidence of comorbid conditions such as seizures, attention-deficit disorders, anxiety, bipolar disorder, or depression.

"Despite minimal evidence of the effectiveness or appropriateness of multidrug treatment of ASD, psychotropic medications are commonly used, singly and in combination, for ASD and its co-occurring conditions," the authors write.

More information: Psychotropic Medication Use and Polypharmacy in Children With Autism

Dyslexia: The First 100 most commonly used words chart

High frequency words are quite simply those words which occur most frequently in written material. For example, "and", "the", "as" and "it".

They are often words that have little meaning on their own, but they do contribute a great deal to the meaning of a sentence.

Some of the high frequency words can be sounded out using basic phonic rules, e.g. "it" is an easy word to read using phonics.

However, many of the high frequency words are not phonically regular and are therefore hard to read in the early stages.

These words are sometimes called tricky words, sight words or camera words.

In addition to being difficult to sound out, most of the high frequency words have a rather abstract meaning which is hard to explain to a child.

Below you can download our first 100 and second 100 most commonly used words chart for your classroom as a display or simply to put in front of your child when they are doing their homework to assist them with spelling.

Download First 100 High Frequency Words Chart - Bold Print.   

Download Second 100 High Frequency Words Chart - Bold Print.