Endotoxin-Induced Inflammation Worsens Depressive Symptoms in Older Adults with Insomnia: JAMA

Researchers then tracked changes in mood using the Profiles of Mood States depression subscale (POMS-D), along with secondary measures of depressive symptoms and inflammatory cytokine levels. Results were striking. Compared to controls, participants with insomnia who received endotoxin showed a 3-fold greater increase in depressive mood (interaction F₁₀,₁₄₇₈ = 4.7; P < .001).

These effects persisted longer and were clinically meaningful. Interestingly, both insomnia and control groups had similar rises in cytokines, but only the insomnia group showed a link between inflammation and mood changes (β = 0.33; 95% CI, 0.26–0.41; P < .001). These findings highlight how insomnia may amplify emotional responses to inflammation, even in the absence of clinical depression.

recommend close monitoring of depressive symptoms in older adults with insomnia during infections or other pro-inflammatory events. Prevention strategies that address both sleep dysfunction and inflammation-related risk are crucial.