Persistent Insomnia Symptoms Linked to a Greater Depression Risk

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A study found persistent or progressive insomnia symptoms are associated with greater risks of developing depression.¹ Si-Jing Chen, from Université Laval in Quebec, will present the research at the SLEEP 2024 Annual Meeting in Houston.

Insomnia is a known risk factor depression. According to Johns Hopkins Medicine, people with insomnia may have a tenfold greater risk of developing depression than people who sleep well.² Not only that, 75% of people with depression often have trouble falling or staying asleep.

Sleep experts say either one can increase the risk of the other. Insomnia can lead to depression and vice versa. Poor sleep may make it hard for someone to regulate their emotions and increases their risk of developing depression in the future. As with depression, individuals often face daily stresses, such as concerns related to finances, spouses, a commute, that can keep them up at night.

Although insomnia is a known risk factor for depression, insomnia’s long-term effect on depression was not well-studied.¹

Chen and colleagues sought to identify the various trajectories of insomnia symptoms over 5 years and assess their associations with depression in adults. They leveraged participants from a population-based study on insomnia in Canada who completed annual sleep and health status surveys for 5 consecutive years.

The current study only included participants who did not have depression at baseline and had data on their depression status for ≥ 1 follow-up time. Investigators identified potential depression cases using a cutoff score of ≥ 20 on Beck Depression Inventory-II.

The team used latent growth mixture modeling to identify trajectories of insomnia symptoms over the 5 years, measured by the Insomnia Severity Index (ISI).

The study included 2725 participants with a mean age of 49.5 years (range: 18 – 94 years) and more than half female (60.9%). Participants were broken into 5 insomnia trajectory groups: good sleepers (23.9%), individuals with stable low insomnia severity (4.8%), subthreshold cases with gradual improvement (6.1%), and individuals with persistent insomnia symptoms (30.4%).

Investigators found the 4 insomnia trajectory groups all demonstrated greater risks of developing depression at follow-up periods, compared with good sleepers. The progressive insomnia symptom group especially had a greater depression risk (relative risk [RR], 18.80; 95% confidence interval [CI], 9.94 – 35.55).

Chen and colleagues observed subthreshold cases with gradual improvement were less likely to develop depression than those with persistent (RR, 0.55; 95% CI, 0.35 – 0.86) and progressive insomnia symptoms (RR, 0.34; 95% CI, 0.21 – 0.56). Even after removing the sleep item from the Beck Depression Inventory-II, the results stayed the same.

“Our findings indicate that insomnia symptoms, particularly when becoming persistent or progressive, are associated with greater risks of developing depression, which underscores the importance of timely addressing and managing insomnia in the prevention of depression,” investigators concluded.

References

1. ^{Chen, S, Ivers, H, Sevard, J, et al. Trajectories of Insomnia Symptoms and Prediction of Depression in Adults: A 5-Year Longitudinal Study. Abstract presented at SLEEP 2024. Houston, TX. June 1-5, 2024.}
2. ^{Depression and Sleep: Understanding the Connection. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/depression-and-sleep-understanding-the-connection#:~:text=Depression%20and%20sleep%20problems%20are,falling%20asleep%20or%20staying%20asleep. Accessed May 31, 2024.}