MRH Chemistry

ADHD diagnoses depend on a child's age relative to classmates and the teacher's perceptions of whether the child has symptoms.

ADHD is the most commonly diagnosed behavioral disorder for kids in the United States, with at least 4.5 million diagnoses among children under age 18, according to the Centers for Disease Control and Prevention.

However, there are no neurological markers for ADHD

Overall, the study found that about 20 percent -- or 900,000 -- of the 4.5 million children currently identified as having ADHD likely have been misdiagnosed.

"Too often, people dismiss ADHD as being down to bad parenting or poor diet. As a clinician, it was clear to me that this was unlikely to be the case. Now we can say with confidence that ADHD is a genetic disease and that the brains of children with this condition develop differently to those of other children."

The condition is highly heritable -- children with ADHD are statistically more likely to also have a parent with the condition and a child with an identical twin with ADHD has a three in four chance of also having the condition.

"Children with ADHD have a significantly higher rate of missing or duplicated DNA segments compared to other children and we have seen a clear genetic link between these segments and other brain disorders," explains Dr Nigel Williams. "These findings give us tantalising clues to the changes that can lead to ADHD."

ADHD is not caused by a single genetic change, but is likely caused by a number of genetic changes, including CNVs, interacting with a child's environment," explains Dr Kate Langley.

. But remember, genes are not everything.

. And that somewhere else is our

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behavior

If 40-80% of BMI comes from genes, then 20-60% comes from somewhere else

possibly tell how much of someone's weight is due to genes? And how much is due to life style choices? One way scientists try to pick apart genetic and environmental causes is to study sets of identical twins. Identical twins have the same DNA but can be put in different environments. This lets scientists directly tell what is due to genetics and what is due to genes. For example, in one study of obesity, sets of identical twins were fed extra food and forced to behave similarly (same amount of exercise, eating, etc.). During the study both twins in an identical twin pair gained about the same weight. But there were huge differences in the amounts of weight gained between sets of twins. This kind of study tells us that the tendency to gain more or less weight is in our genes. But twin studies can also show that some aspects of weight have to do with behavior too. For instance, scientists looked at identical twin pairs that exercised different amounts. As expected, the twin that exercised more weighed less. This shows that weight is not just genetic and that behavior is not all genetic. The fact that the twins had different exercise patterns definitely suggests that what we weigh has a large environmental component. So how much we weigh has to do with both our genes and our behavior. Just because someone's parents are heavy that does not mean their children will be heavier too. But it might mean that they will have trouble keeping the weight off. Good exercise habits and eating healthy foods can help maintain a normal weight. The opposite is also true. Your genes can predispose you to be normal weight. But if you eat too much food and do not exercise enough to use up the extra energy, then you will gain weight and eventually become overweight. Weight is really just a product of energy taken in (food you eat) minus energy used (for exercise, for heating our bodies, for helping digest our food, etc). So to lose weight, all you have to do is use more energy than you eat. And to gain weight, you just have to eat more food than you use up. Sounds simple, right? But of course it isn't--partly because of genes. Our genes can affect the amount of weight lost from dieting and exercise. They can also affect how much weight is gained when we eat too much. Our genes make proteins that work together to control everything from how often we get hungry to how we use energy from food. They even control how much exercise we can do at a time. Because our genes tell our bodies how to handle the food we eat, it's often hard for us to achieve a certain target weight. But what we weigh isn't only due to our genes. Katie Cunningham More Information How identical twins can look different even with the same genes.Obesity genesAppetite genes Back to Conditions Search Ask a Geneticist His parents were probablyoverweight. But notnecessarily.Identical twin studies showthat our weight is partgenetic and part en

Jason Babcock is the founder of Positive Science, a New York company that has developed eye-tracking devices over the last decade

John Franchak, a doctoral student at NYU and leader of the project

infants would be looking at their mothers constantly because that was common knowledge within [the field of] social cognition with infants." But in a room full of toys scattered everywhere and obstacles to climb on and crawl on, the infants only looked toward their mothers about half the time.  And even if they did look at their mothers, they looked at their mothers' faces only about 15 percent of the time.

toddlers almost always look directly at the object when reaching for it.

Toddlers are able to use information from their peripheral vision and still walk very well.

Another interesting finding was that while infants look directly at an obstacle before walking onto or over it, 75 percent of the time they don't always have to.

According to Franchak, down the line it could offer more research applications that could help infants with developmental disorders, medical research and applied research.   

C-section babies have a pattern of "at risk" microorganisms in their gastrointestinal tract that may make them more susceptible to developing the antibody Immunoglobulin E, or IgE,

children do think before they speak.

"If you're trying to lose weight, getting enough sleep gives you a fighting chance."

The model examines the looking-learning behavior of infants as young as 6 weeks through one year of age, through 4,800 simulations at various points in development involving multiple stimuli and tasks. As would be expected, most infants introduced to new objects tend to look at them to gather information about them; once they do, they are “biased” to look away from them in search of something new

an infant will linger on something that’s being shown to it for the first time as it learns about it, and that the “total looking time” will decrease as the infant becomes more familiar with it.

infants who don’t spend a sufficient amount of time studying a new object—in effect, failing to learn about it and to catalog that knowledge into memory—don’t catch on as well, which can affect their learning later on.

Sammy Perone, a post-doctoral researcher in psychology at the UI and corresponding author on the pape

To examine why infants need to dwell on objects to learn about them, the researchers created two different models. One model learned in a "responsive" world: Every time the model looked away from a new object, the object was jiggled to get the model to look at it again. The other model learned in a "nonresponsive" world: when this model looked at a new object, objects elsewhere were jiggled to distract it. The results showed that the responsive models“learned about new objects more robustly, more quickly, and are better learners in the end,

infants can familiarize themselves with new objects, and store them into memory well enough that when shown them again, they quickly recognized them

“if that’s the case, we can manipulate and change what the brain is doing” to aid infants born prematurely or who have special needs, Perone adds.