Does our type of sleep influence the risk of depression?
Depression is becoming increasingly common these days. Researchers have now found that if you get up early in the morning, women can reduce their risk of developing depression.
- Researchers examined the so-called sleep-wake preferences and depression rates of 32,000 female nurses.
- Early risers had a 12 to 27 percent lower risk of depression.
- Night people were married less frequently, generally lived more often alone and were more prone to irregular sleep patterns.
- The same genetic pathways that influence sleep type can also affect our mood.
In their current study, scientists from the University of Colorado Boulder and Brigham and Women’s Hospital found that women who wake up early in the morning have a reduced risk of developing depression. The doctors published the results of their study in the English-language journal "Journal of Psychiatric Research".
Early risers reduce their risk of depression
If you're one of those women who get out of bed early in the morning, it reduces their risk of depression. This could be due to the fact that so-called early risers are exposed to daylight for longer, the authors suspect.
Data from 32,000 women were evaluated
For their study, the doctors analyzed the data from more than 32,000 nurses. The experts found that our sleeping habits have an impact on the risk of developing depression. These sleeping habits are partly determined by our genetics. Even after considering environmental factors such as exposure to light and work plans, which also influence sleep behavior, the result remained. "The results found could be related to the overlap of genetic pathways related to sleep type and mood," said study author Celine Vetter of the University of Colorado Boulder in a press release.
Night people have a greatly increased risk of depression
Previous studies have shown that so-called revelers suffer from depression up to twice as often. However, since these studies often used data from a single point in time and did not take into account many other factors that also influence the risk of depression, it was difficult to determine whether depression causes people to stay awake longer or whether our type of sleep increases the risk of depression, the doctors explain.
Participants were asked about their sleeping behavior
To clarify the question, the researchers used data from women with an average age of 55 years. In 2009, all subjects were still free from depression, the scientists explain. These women were asked about their sleeping habits. 37 percent of the participating women described themselves as early risers, 53 percent described themselves as intermediate types and ten percent of the participants were so-called night people.
Subjects were medically monitored for four years
The women were medically monitored for four years to determine which participants developed depression. The researchers also explain various risk factors for depression, such as body weight, physical activity, chronic illnesses, length of sleep or night shift work.
The risk of depression among early risers was reduced by up to 27 percent
The researchers found that late sleepers or revelers are less likely to be married, more likely to live alone, and are more likely to smoke. In addition, such people have unpredictable sleep patterns, the doctors explain. Taking these factors into account, they found that early risers were still 12 to 27 percent less likely to experience depression than intermediate types studied. Night owls were at six percent higher risk than the examined intermediate types, although this finding was not statistically significant, explain the doctors.
Sleep type is heavily influenced by genetics
The results show that our type of sleep has an effect on the risk of depression that is not due to environmental and lifestyle factors, says Vetter. The tendency to be an early bird or a night person is between 12 and 42 percent genetic. Some studies have already shown that certain genes (including PER2 and RORA) affect when we prefer to sleep and when we are awake, while also influencing the risk of depression.
What is influenced by our type of sleep?
When and how much light the human body receives is influenced by the type of sleep. The effect of light also affects the risk of depression, adds Vetter. Although the study suggests that sleep type is an independent risk factor for depression, it's only a minor effect. This does not mean that night people are automatically doomed to develop depression, the expert adds.
Notes for night people
Night people should try to get enough sleep and exercise and spend more time outdoors. In addition, those affected should insulate the light at night and try to get as much light as possible during the day, the scientists advise. (as)