A study conducted by a Japanese research team from Jikei University School of Medicine in Tokyo has revealed a significant discovery regarding the potential trigger for depression later in life. The team's findings, published in a U.S. science journal in February, suggest that an infection with the human herpes virus type 6 (HHV6) during infancy could play a role in the development of depression. While genetic factors have long been suspected as likely causes of depression, this research introduces the concept that certain virus infections in early life may also contribute to the mental health condition.
The team focused on SITH1 proteins produced by HHV6, particularly noting that individuals with these proteins are more susceptible to developing depression. The HHV6 virus, commonly acquired in infancy and carried throughout life, particularly manifests in saliva when a person feels run down, eventually spreading to the brain and potentially leading to reinfection which produces SITH1 proteins. Through experiments involving mice, the researchers were able to uncover part of the mechanism through which depression develops, shedding light on the link between the virus and mental health issues.
one that readily produces the protein and another that does so with difficulty. The researchers found that a significant percentage of patients with depression were infected with the type of HHV6 that can easily produce SITH1 proteins, compared to healthy individuals. This observation highlights a potential connection between the virus's gene types and susceptibility to depression. Additionally, the study showed that HHV6 is mainly transmitted from mothers to infants, raising the possibility that the virus transmitted from the mother could make the child more prone to developing depression, contrary to the belief that genetic factors alone were closely linked to mental health issues.