Sunny Climates Associated With Lower Prevalence Of ADHD
October 21, 2013

Sunny Climates Associated With Lower Prevalence Of ADHD

Brett Smith for - Your Universe Online

Attention-deficit/hyperactivity disorder, or ADHD, is the most common childhood psychiatric disorder, yet also one of the least understood.

A recently published study in the journal Biological Psychiatry may shed new light on the condition, literally, as scientists have found sunny climates appear to have a preventative effect on children developing the disorder.

"The reported association is intriguing, but it raises many questions that have no answers," commented Dr. John Krystal, Editor of Biological Psychiatry. "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?"

Just a cursory look at data maps released by the Centers for Disease Control and Prevention (CDC) and the Department of Energy that show ADHD occurrence rates and solar intensities, respectively around the country, point to an interesting pattern – one indicative of an association.

In the study, researchers from Utrecht University in the Netherlands looked at multiple data sets from the US and nine other countries. After considering confounding factors, the study team found regions with the highest sunlight intensity had the lowest prevalence of ADHD, an indication that sunlight intensity has a 'protective' effect for ADHD.

The Dutch team also looked at this same relationship with respect to autism and significant depressive disorder diagnoses. They discovered their findings were specific to ADHD, with no affiliations seen between the other two disorders.

The study researchers cautioned against reading too much into their findings and said further work on the subject is necessary, including an eventual replication of these findings. They also noted the findings only point to an association -- not a cause-and-effect relationship -- between ADHD and solar intensity levels.

According to lead study author Martijn Arns, an expert of depression and ADHD at Utrecht University, the study’s preliminary findings could lead to more significant implications.

"From the public health perspective, manufacturers of tablets, smartphones and PCs could investigate the possibility of time-modulated color-adjustment of screens, to prevent unwanted exposure to blue light in the evening,” Arns said.

"These results could also 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,” he added. “For example, skylight systems in classrooms and scheduling playtime in line with the biological clock could be explored further."

ADHD is marked by a lack of focus, low attention capacity, hyperactivity, and impulsivity. Previous studies have found normal brain maturation is delayed in children with the condition. Many people with ADHD also report sleep problems and disorders. So much so, that sleep disorder treatments and other interventions designed to restore normal circadian rhythms have been shown to be beneficial in treating ADHD symptoms.

Thought to affect between 5 and 7 percent of the population, some experts have questioned if ADHD should even be labeled a disorder. Controversial author, radio personality and former psychotherapist Thom Hartmann has said that children with ADHD should be looked at as “different” not “disordered.”