Increased Sunshine Time Decreases Mental Health Distress

A new study shows that the amount of exposure to sunshine affects the mental health of the population at large, and not just those diagnosed with Seasonal Affective Disorder (SAD).

Researchers at Brigham Young University (BYU, Salt Lake City, UT, USA) conducted a study to examine a range of weather and atmospheric phenomena and their association with time-bound mental health data. In all, 19 different weather and pollution variables were examined and correlated with an archive of self-reported mental health data available for 16,452 university students participating in mental health treatment over a period of six years.

The results showed that seasonal changes in sun time could best account for relationships between weather and pollution variables and variability in mental health distress. A separate analysis that examined study participants suicidal ideation – though not statistically significant – demonstrated a similar pattern. Initial results also showed a relationship between pollution and changes in mental health distress; however, this was mediated by sun time. The study was published in November 15, 2016, issue of Journal of Affective Disorders.

“On a rainy day, or a more polluted day, people assume that they'd have more distress. But we didn't see that. We looked at solar irradiance, or the amount of sunlight that actually hits the ground,” said lead author Professor Mark Beecher, PhD, of the BYU counseling and psychological services. “We tried to take into account cloudy days, rainy days, pollution, but they washed out. The one thing that was really significant was the amount of time between sunrise and sunset.”

Light is a major factor in SAD, which in manifested by emotional depression, a drop in physical energy, increased appetite, and drowsiness, all resulting from the complex relationship between sunlight, melatonin, and serotonin. As darkness falls, melatonin levels naturally increase; as the morning light emerges, melatonin levels decrease. Serotonin levels rise following exposure to bright light.

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