While modern society has given us enormous advancements to continue working and playing beyond the setting sun, such changes to our day/night rhythms may make us more prone to depression.

This reveal comes courtesy of a new study published in Molecular Psychiatry that links light pollution with an increase in major depressive disorder. Researchers used female hamsters (since females, both rodent and human, are more likely to suffer from depression) and exposed them to different sources of bright and dim lights; with the latter typical of light pollution found in urban areas.

After four weeks of this exposure, the hamsters were producing more TNF – a protein secreted in response to injury or inflammation. Released consistently, that alone could play a role in increased risk for depression. The researchers also noted that melatonin, a powerful antioxidant and “synchronizer” of our biological clocks, was suppressed.

“The results we found in hamsters are consistent with what we know about depression in humans,” Tracy Bedrosian, the first author the on the new study, told reporters.

The good news is that by simply minimizing the amount of dim light at night, the hamsters biological functions returned to normal levels. So turning off that iPad, television, or bright light above your head a bit earlier could help. For urban dwellers, light-block curtains might also help.

The researchers found that 8 full hours of darkness daily appeared to do the trick.

You can read the full study here – preferably during the daytime hours.