The Nature journal published the largest study on human chronotype, that is the tendency of a person to wake up earlier or later. For this survey, they used samples of 697,828 people.
The sleep chronotype patterns are part of the circadian rhythm. Which is the daily cycle that regulates, hormone levels, and body temperature.

The investigation also proved that the level of light, age, and the times of sleep varies on genes. Morning people are more at risk to mental illnesses, while the night owls are more likely to suffer from alterations such as depression or schizophrenia.
Vía Forbes