Summary of Research on Sleep and Depression
Key Findings
Researchers have found a connection between consistently sleeping less than five hours nightly and an increased risk of developing depressive symptoms. Contrary to previous beliefs, the study suggests that sleep might precede the onset of depression. Genetic data from 7,146 individuals showed that those genetically predisposed to shorter sleep were more prone to depression. On the other hand, a genetic inclination for depression did not increase the odds of shorter sleep.
Key Facts
- People with a stronger genetic predisposition to short sleep (<5 hours nightly) had a heightened likelihood of developing depressive symptoms over a span of 4-12 years.
- Individuals sleeping five hours or less were 2.5 times likelier to show depressive symptoms.
- Sleep duration and depression both carry some hereditary component, with twin studies indicating 35% heritability for depression and 40% for sleep duration variances.
Overall Research Summary
The study, led by UCL researchers, analyzed data from individuals with an average age of 65 and found that short sleep was associated with the onset of depressive symptoms. Both sleep duration and depression are partly inherited from one generation to the next. The study assessed the strength of genetic predisposition among participants and found that people with a stronger genetic predisposition to short sleep were more likely to develop depressive symptoms over 4-12 years, but genetic predisposition to depression did not increase the likelihood of short sleep. Participants who slept five hours or less were 2.5 times more likely to develop depressive symptoms, while people with depressive symptoms were a third more likely to suffer from short sleep. Sleep duration and depression were also found to fluctuate over time.
Research Opinion
As a psychiatrist, I believe that this study’s findings are important in understanding the complex relationship between sleep and mental health. The evidence of a genetic association between short sleep and depression could potentially lead to new interventions and treatment approaches targeting sleep patterns to prevent the onset of depressive symptoms.
Dr Harper Johnson-Smith, MD, Cure of Mind