Sunshine May Mitigate ADHD-related Symptoms

Exposure to sunlight may help to mitigate ADHD-related symptoms, researchers from Yale University discovered.

Despite being the most common childhood psychiatric disorder, researchers are still unsure what causes ADHD, though genetics and other risk factors, such as premature birth, low birth weight and environmental exposures to toxins like lead, clearly play a role. Worldwide prevalence is estimated between 5 to 7 percent; however, it varies greatly on a regional level -- an observation that prompted researchers led by Dr. Martijn Arns to explore a possible relationship between sunlight and ADHD.

The team collected and analyzed multiple data sets from the United States and nine other countries and, in doing so, identified a relationship between solar intensity and ADHD prevalence.

In order to validate their research, the scientists searched for a similar relationship with autism. The findings, they discovered, were specific to ADHD.

Dr. John Krystal is the editor of Biological Psychiatry, which published the study. Krystal points out that while interesting, it's unclear whether this is a case of causation or simply correlation.

"The reported association is intriguing, but it raises many questions that have no answers," he said in a statement. "Do sunny climates reduce the severity or prevalence of ADHD and if so, how? Do people prone to develop ADHD tend to move away from sunny climates and if so, why?"

While Arns agrees that more research is needed to corroborate and further explore the relationship between the two, he argues that the implications are significant.

The results, he says, "point the way to prevention of a sub-group of ADHD, by increasing the exposure to natural light during the day in countries and states with low solar intensity, For example, skylight systems in classrooms and scheduling playtime in line with the biological clock could be explored further."