Body temperature correlates with depressive symptom severity: analysis and extension of prior findings in observational cohorts with more than 19,000 participants.

Objective: Prior studies have reported that higher body temperature correlates with greater depressive symptoms, but did not adjust for potential confounders. Methods: We used linear regression models and linear mixed models to assess associations between self-reported depressive symptoms and body temperature (once-daily self-reported temperature from a thermometer and minute-level distal temperature from a commercially available wearable device, worn on the finger). Adjusted models covaried for biological sex, age, daylight length, ambient temperature, and number of medical conditions. Distal body temperature metrics included awake and asleep temperatures, the asleep-awake temperature difference, and the diurnal temperature amplitude. Distal body temperature models also covaried for daylight length and ambient temperature over time. Finally, we used adjusted logistic regression models to assess associations between all body temperature metrics and four categories of depressive symptom severity. Results: In an adjusted linear regression model, the positive association between depressive symptoms and self-reported body temperature remained significant ( Conclusion: Higher body temperature was associated with increased depressive symptoms, and this association was robust to adjustment for potential confounders. These findings support body temperature as a physiological correlate of depressive symptom severity and motivate further investigation of thermoregulatory measures as part of multimodal approaches for monitoring depressive symptoms.