A Virus May Trigger Depression Later in Life
A research team from the Jikei University School of Medicine in Tokyo has discovered a potential link between a specific virus and the development of depression later in life. This finding challenges the long-held belief that depression is primarily caused by inherited genes.
The team's research, published in a U.S. science journal in February, focuses on the human herpes virus type 6 (HHV6) and its role in producing SITH1 proteins. These proteins have been previously linked to the development of depression.
HHV6 is a common virus that infects almost everyone during infancy. It typically causes a mild fever known as exanthema subitum. While the virus remains dormant in the body after the initial infection, it can become reactivated under certain conditions, such as stress or illness.
When reactivated, HHV6 spreads from the mouth to the nose and then to the brain, producing SITH1 proteins. The research team found that individuals with these proteins are more likely to develop depression than those without them.
Further experiments involving mice confirmed that HHV6 reinfection can affect brain cells, providing insight into the mechanism of depression development.
one that readily produces the protein and another that does so with difficulty. Interestingly, 68% of 28 patients with depression were infected with the easily-producing form, compared to only 29% of 35 healthy individuals.
This suggests that the type of HHV6 a person is infected with may influence their risk of developing depression. Additionally, the researchers found that 47% of patients with depression infected with the easily-producing form had family members with depression, suggesting a potential link between maternal transmission of the virus and vulnerability to the disorder.
While genetic factors have long been associated with depression, this research suggests that the virus itself, rather than the mother's genes, may play a crucial role in making a child susceptible to depression.
Professor Kazuhiro Kondo, a member of the research team, believes that understanding the mechanism behind this link could lead to the development of new treatment strategies for depression.