We have a new clue to depression, and we found it in an unexpected place: body temperature.

The study involved more than 20,000 participants from one hundred countries.

Depression is something that goes beyond our brain. Like many other diseases, this psychological illness manifests itself in other aspects of our physiognomy. For example, our body temperature.

Fever and depression. The study found a link between body temperature and depression. The team responsible for the analysis noticed a positive relationship between the variables, meaning the occurrence of depressive symptoms was associated with higher body temperature in the participants.

The dependence was proportional: the greater the severity of symptoms, the higher the body temperature. They also observed an apparent association between temperature variability and depressive symptoms, but this was not found to be statistically significant, so no conclusions can be drawn about it.

Apart from statistical incidence, little is known about this association. For example, the team noted that it was still a mystery whether this increase in body temperature could be due to loss of control, increased production of temperature through metabolic processes, or whether it was a combination of factors.

More than 20,000 participants. To conduct the study, the team collected information from 20,880 participants from 106 countries. In the study, which lasted seven months in 2020, participants wore a thermometer device to measure their body temperature and reported daily temperature and depression symptoms.

“To our knowledge, this is the largest study examining the association between body temperature (both self-measured and using wearable sensors) and depressive symptoms in a geographically large sample,” psychiatrist Ashley Mason explained in a press release. work. The study was published in the journal Scientific reports.

An old suspicion. Although this is probably the largest analysis, it is not the first analysis to point to this relationship. A study published in 2003 indicated the existence of this relationship and its possible connection to the 5-HTT protein, the “serotonin transporter.”

Correlation and cause. The present study finds an association between temperature and depression but does not indicate a possible form of causal direction, if any. Based on known data, it is not possible to determine whether depression causes fever or whether elevated body temperature may increase the risk of depression.

It also cannot be ruled out that there is an underlying cause for both that is not seen by the analysis: stress or inflammatory processes can independently cause both depressive symptoms and increased body temperature.

Cold or heat as therapy? Understanding what’s going on can help us better understand depression and therefore give us the tools we seek to combat it. Until now, heat has been used to improve the condition of patients. The team adds that these therapies may make sense because of a “rebound effect” that helps the body regain its ability to regulate heat.

In Hatak | The Great Mystery of Our Body Temperature: It Continues to Fall Around the World, and We Still Don’t Know Why

Image | Polina Tankilevich