Potential Genetic Overlap Between Insomnia and Sleep Symptoms in Major Depressive Disorder: A Polygenic Risk Score...

Area of Science:

• Genetics
• Sleep Medicine
• Psychiatry

Background:

• Insomnia and hypersomnia are more prevalent in individuals with depression compared to the general population.
• Sleep disturbances significantly impact the course of depression.
• Recent large-scale genome-wide association studies (GWAS) have identified genetic factors associated with insomnia.

Purpose of the Study:

• To determine if polygenic risk score (PRS) for insomnia, derived from population-based GWAS, predicts insomnia in individuals with major depressive disorder (MDD).
• To investigate the genetic overlap between insomnia in the general population and insomnia in a depressed cohort.

Main Methods:

• Utilized data from the largest available GWAS for insomnia and other sleep traits.
• Calculated PRS for sleep variables from population-based samples.
• Tested PRS predictive power for sleep variables in Psychiatric Genomics Consortium - Major Depressive Disorder (PGC MDD) subjects.
• Performed leave-one-out analysis to assess the influence of individual studies.

Main Results:

• A significant association was found where PRS for insomnia, using a p-value threshold of 0.05, predicted insomnia in the PGC MDD sample (R² = 1.75e-3, p = 0.006).
• Less than 1% of variance in insomnia was explained by the variants tested, consistent with the polygenic nature of both depression and insomnia.

Conclusions:

• This study is the first to explore the genetic overlap of insomnia between the general population and a major depressive disorder sample.
• The findings suggest shared genetic factors contribute to insomnia in both general and depressed populations.
• Identifying this genetic overlap has potential implications for developing novel therapeutic targets for insomnia in depressed individuals.