Researchers recently took a look genomic data from 700,000 people, all of whom had completed a DNA analysis from the company 23andMe and opted into the study. Participants were asked to complete a health survey, which asked whether or not they considered themselves a morning person or a night owl.

While the study didn’t find any difference between being a morning or night person and a person’s risk of obesity of diabetes, it did find a connection between night owls and being prone to depression, anxiety, and schizophrenia. The results of the study were published this week.

That said, the reason for the link is currently unknown, and instead points out a need for further research in the area.

Some theories include the genes in early risers potentially offering some sort of protection against mental health issues, the amount of light early risers are exposed to, and perhaps the societal advantages of feeling more awake in a 9-5 world.

In the study, both groups of people ultimately got around the same amount of sleep at night, and that’s important. Another recent study found that not getting enough sleep at night can ultimately lead to coronary artery disease or even a stroke.