What is the relationship between sleep and depression? Between 10 and 24 years old, the rate of depression increases rapidly, and an onset of major depression disorder (MDD) during this time normally means a lifetime of depressive episodes. Therefore, it is very important to determine if something could be changed to prevent or modify the onset of MDD. One potentially modifiable behavior is sleep. Sleep changes a great deal during adolescents, and a lot of children and adolescents with MDD have sleep problems.
There have been a few studies that have suggested that poor sleep and sleep disturbances could lead to depression, but those have been in older teens and adults. Therefore, a team of researchers from SRI International, University of Pittsburgh, University of Melbourne, and the University of Witwatersrand decided to use previously collected data from a very large study (Adolescent Brain Cognitive Development study) to see how both sleep disturbances and total sleep time were associated with depression symptoms both at baseline, and one year later in early teens without a diagnosis of MDD.
In this analysis, sleep disturbances included disorders of starting and maintaining sleep, disorders of excessive sleeping, and disorders of transitioning between sleeping and waking (all three of these disorders have been previously associated with mental health concerns), and number of hours of typical total sleep. The mental health measures included internalizing symptoms (anxious, depressive, overcontrolled), externalizing symptoms (aggressive, hyperactive, non-compliant, and undercontrolled), and depression symptoms.
A total of 11,875 participants, aged 9-10 years, were included in this study from 17 different states. This group of participants were about equally males and females, and majority non-Hispanic participants. On average, the scores for these participants on the mental health scales were within the normal range, and there were very low levels of sleep disturbance problems at baseline. At baseline, the researchers found that more sleep disturbances were associated with poorer mental health.
The most important main results from this study were that even accounting for mental health symptoms at baseline, baseline sleep disturbances significantly predicted mental health symptoms one year later. Looking at only the depression symptoms model, the researchers found an interaction with sex, in that the association between excessive sleeping at baseline and depression symptoms 1 year later was stronger among girls than among boys. These researchers also found that short baseline total sleep (5-7 hours per night) also significantly predicted externalizing symptoms (aggression, hyperactivity, non-compliance, and being undercontrolled) 1 year later.
These results are incredibly important, because they show that problems with sleep disturbance in pre-teens can significantly predict their depression symptoms one year later. They also found that girls might be at higher risk of developing depressive symptoms resulting from sleep problems compared to boys. These results were also seen among pre-teens that the vast majority did not have mental health issues at baseline, so these results are very generalizable even to those who do not believe they have or will have mental health symptoms in the future. Therefore, preventing depression symptoms and preventing MDD is incredibly important, and it seems as though fixing sleep problems might be a potential way to achieve that goal.