Short Sleepers May Face Increased Risk for Depression, New Study Finds

Getting less than five hours of sleep per night may raise your risk of developing depression. While poor sleep is often seen as a side effect of depression and other mental health conditions, a new genetic study suggests the opposite may be true. In other words, short sleep may precede depressive symptoms.

The lead author explains, "We have this chicken or egg scenario between suboptimal sleep duration and depression. They frequently co-occur, but which comes first is largely unresolved." To explore this further, researchers analyzed genetic and health data from about 7,100 people with an average age of 65.

The study found that participants with a strong genetic predisposition to short sleep were significantly more likely to develop depressive symptoms. In contrast, those with a strong genetic predisposition to depression were not more likely to experience short sleep. The researchers also examined non-genetic associations between sleep duration and depression and found that short sleepers were 2.5 times more likely to develop depression.

These findings suggest that poor sleep precedes depressive symptoms. Previous investigations have shown that depression is about 35% heritable, and genetic differences account for 40% of variations in sleep duration.