Nature vs. Nurture
ADHD is a neurobiological disorder. Differences in brain chemistry and activity have been well documented in numerous studies. Even so, the question of whether the environment contributes to ADHD symptoms remains. A study published June 25, 2015 in Scientific Reports looked at this question by comparing the length of eye gaze of newborns between one and four days old and the later incidence of behavioral issues. Previous research completed by the same scientists showed that difference in attention style in baby’s between the ages of 4 and 10 months old could predict behavior and temperament in childhood. The researchers pointed out that even at this young age, there could be environmental factors, such as amount of stimulation, that could contribute to the results. The aim of the new study was to eliminate the possibility of environmental factors and the researchers looked at infants between the ages of one and four days old.
In the recent study, scientists looked at 80 newborns. Each newborn was shown images and the “dwell time” was measured. Dwell time is the amount of time a gaze remains on a given stimuli. The study was followed up with parent questionnaires when the children were between 3 and 10 years old. The results of the study showed that the babies who had the shortest dwell times:
- Were more hyperactive and impulsive later in childhood
- Had more behavioral problems in childhood
The scientists expressed their surprise at the wide differences in dwell time between the infants and how well visual attention predicted later outcomes.
What It Means
It is well accepted that ADHD runs in families, showing that, in many cases, it is inherited or “in your genes.” But there has also been the question of how much parenting styles and the environment can influence or exacerbate symptoms of ADHD and behavior. The researchers believe this study shows that these considerations - nurture - are minimal. Any environmental factors that might influence ADHD are those that occur in the womb, not after birth.
The Eyes as a Mirror to ADHD
A study completed in 2014 at Tel Aviv University found that analyzing eye movements and blinking can help to diagnose ADHD. In that study, participants took a standardized, computerized ADHD test. About half of the participants had ADHD and half did not. Those with ADHD showed more involuntary eye movements and blinking during the test than those who did not have ADHD. The researchers of this study expressed hope that the information could be used to develop a diagnostic tool for ADHD.
Based on these studies, our eyes might hold the key to diagnosing ADHD or at least having an objective test to help prepare for possible behavioral difficulties during childhood.
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