In the largest study of its kind, researchers have found that people suffering from major depressive disorder (MDD) are also more likely to have higher body temperatures, opening the door to treatments that could help regulate this function and potentially alleviate debilitating symptoms.
University of California San Francisco (UCSF) researchers analyzed collected data from more than 20,000 individuals across seven months and from 106 countries. Using the same participant pool, scientists looked at the self-reported temperature data of 20,863 individuals (53% male, 47% female) and the Oura Ring wearable sensor data of 21,064 people (56% male, 44% female). In total, 559,664 body temperature assessments were taken, translating to an average of 27 readings per day for each participant.
At the same time, monthly mental health assessments were completed, using the widely used Patient-Reported Outcomes Measurement Information System (PROMIS) depression measure, which is a reliable ranking system to gauge depression levels (mild to severe).
“To our knowledge, this is the largest study to date to examine the association between body temperature – assessed using both self-report methods and wearable sensors – and depressive symptoms in a geographically broad sample,” said the study’s lead author Ashley Mason, associate professor of psychiatry at UC.
What they found was that body temperature was linked to the severity of depression symptoms, independent of variables such as age and sex. They also found that an increase in severity levels matched corresponding higher temperatures. While they also spotted a trend in higher depression scores and a lack of temperature fluctuation over 24-hour periods, the data wasn’t statistically significant.
Previous studies have sampled less than 300 participants, and in a controlled setting. This real-world data analysis beyond a laboratory environment is critical in understanding the relationship between body temperature and MDD – and to develop new treatment methods centered around thermoregulatory dysfunction.
While it sounds counterintuitive, potential treatments include temperature-raising therapies such as hot yoga and sauna sessions, to trigger the body's self-cooling mechanisms.
“Ironically, heating people up actually can lead to rebound body temperature lowering that lasts longer than simply cooling people down directly, as through an ice bath,” said Mason. “What if we can track the body temperature of people with depression to time heat-based treatments well?”
MDD was ranked the third cause of the burden of disease worldwide in 2008, and the World Health Organization believes it will ascend to the number-one spot by 2030. Because it’s multifactorial, linked to biological, genetic, environmental and psychosocial factors, it’s incredibly complex to effectively treat.
While little is still known about how body temperature and depression – such as whether it’s tied to dysfunctional self-cooling mechanisms or heat-generating metabolic processes, the researchers believe their results make the case for exploring novel thermoregulatory therapies.
"Clarifying the biological pathways through which body temperature is altered in some individuals with depression may reveal more specific pathogenic mechanisms amenable to targeted treatment for individuals with depression and elevated body temperature," the researchers noted in the study.
“Given the climbing rates of depression in the United States, we’re excited by the possibilities of a new avenue for treatment,” said Mason.
The research was published in the journal Scientific Reports.
