People who are depressed very commonly do not sleep well. Thus poor sleep is typically considered to be one of the hallmarks of clinical depression. It turns out that the opposite may be true as well. Not getting enough sleep on a continual basis may lead to depression. So, can you avoid depression by getting enough sleep? Is the chronic lack of enough sleep the real cause of depression in many people? Or is it merely a warning sign of impending depression?
Sleeping Less Than 5 Hours a Night Raises the Risk of Depression
Researchers at the University College of London found in a study that getting less than 5 hours of sleep commonly led to depression. They were looking at folks with an average age of 65 years. The study did not start out trying to judge cause and effect. What they first found was an association between insufficient sleep and depression. When they looked at genetic susceptibility to depression and short sleep patterns, they concluded that not getting enough sleep often comes first and symptoms of depression come next.
Predispositions to Little Sleep Versus Predispositions to Depression
In the United Kingdom they have the English Longitudinal Study of Aging, AKA ELSA. The researchers in this study that looked at sleep and depression recruited 7,146 people from that study. Within that group there were people whose genetic makeup was such that they and many of their relatives typically got by on very little sleep every night. And there were people with family histories of depression. When they crossed checked for depression in the little sleep group and for little sleep in the prone-to-depression group, they found this. Within 4 to 12 years, people who habitually went without enough sleep were prone to develop depression. Folks with a family history of depression did not end up sleeping less in the coming years.
Genetic Predisposition for Depression or Insufficient Sleep
In the ELSA study they do genetic testing. They have discovered thousand of genetic variants that correlate with people developing depression and also ones that correlate with people not getting enough sleep or sleeping excessively. Within this study the researchers looked at both genetic and non-genetic predispositions for sleep patterns and symptoms of depression.
Routinely sleeping five hours or less per night makes people two and a half times more likely to develop symptoms of depression. People who were already depressed were three times more likely to not sleep well.
Interestingly, sleeping more than nine hours a night predisposed people to be one and a half times more likely to become depressed. However, when they looked out four to twelve years this correlation had gone away.
What Does the Sleep and Depression Study Tell Us?
This was a retrospective study. They looked back in time and found correlations between lack of sleep and depression. The study confirmed that folks who are depressed tend not to sleep well. They also found that not sleeping well is a predictor of getting depressed. However, the study does not tell us if poor sleep is simply a marker for pending depression or a cause of it.
To find out that part researchers will need to try to affect peoples’ sleep patterns going forward and see if that makes a difference in the incidence of depression or not. This is a bit like when they assumed that a high cholesterol caused heart disease but did not have clear evidence until they compared folks who received treatment to lower their cholesterol with those who did not receive treatment. Those studies proved that treating and lowering cholesterol reduces the incidence of heart disease. The same approach will be necessary to prove a lack of sleep and depression correlation.
Should You Be Getting Enough Sleep?
Not getting enough sleep is related to a lot of health problems and not just depression. Obesity in adults and children, diabetes and impaired glucose tolerance, cardiovascular disease and hypertension, anxiety symptoms, alcohol abuse, and depression are all related to not getting enough sleep. So, the quick answer is, get enough sleep because it likely help you avoid a lot of problems with your physical and mental health. While we are sleeping our brain and our body repair themselves and get us ready for the next day. When we do not sleep well, we do not carry out these repair and maintenance functions and that has a toll on life.