A research team has confirmed that a virus-derived protein holds the key to determining why overfatigue and major stress can lead to depression.

The researchers, from the Jikei University School of Medicine, discovered that the protein dramatically increases the risk of depression. They said that people who have this protein are 12.2 times more likely to develop this mental health problem.

HHV6 is the virus that causes exanthema subitum, a disease in infants. Almost all people are infected during their infancy, and after that, they carry the latent virus in their bodies.

Normally, the virus remains dormant, but when the body is fatigued, HHV6 is awakened and is present in saliva to escape from the weakening host. Some of the virus reaches and infects the olfactory bulb, the center in the brain connected to the sense of smell, by flowing up from the mouth to the nose.

The Asahi Shimbun: Virus-derived protein triggers depression - June 15, 2020