Researchers at Ohio State University Medical Center have found that hamsters exposed to chronic dim light at night over a few weeks were prone to symptoms of depression. The darkness-deprived rodents reduced their physical activity compared to hamsters in normal light-dark conditions, showed greater signs of distress when stressed, and were less interested in things that once delighted them, like sugar water, according to Time.com. The research suggests the same could be true for humans.

The American Medical Association also warns that over-exposure to light suppresses melatonin, a hormone believed to fight tumors and cancer. Plus, changes in the body’s circadian rhythms from light-dark imbalances could make one more susceptible to obesity, diabetes and reproductive problems.

Meanwhile, light pollution from TVs, computers, streetlights, mobile devices, insomniacs’ bedside lamps, traffic and neighbors has supposedly surged over the past 50 years, a trend that coincides with increases in depression, the article states.