Herpesviruses possible cause of mental illnesses

Study: Viruses are involved in the development of mental illness

Herpes is extremely common. Anyone who has once been infected with the virus will not let go. It slumbers to break out again and again in the form of annoying bubbles. A German-American research team found a link between herpesviruses and the development of mental illnesses such as depression, bipolar disorder and schizophrenia. According to the scientists, the viruses disrupt the development of nerve cells and hinder the immune system at important stages of development.

Researchers from the Institute of Virology and Immunobiology at the University of Würzburg have recently provided new information on the development of mental illness together with American colleagues at the Stanley Medical Research Institute: The human herpesvirus HHV-6 can infect nerve cells and possibly cause cognitive disorders. These disorders could be the cause of depression and bipolar disorder. The study results were recently published in the journal "Frontiers in Microbiology".

Can viruses cause mental illness??

The current study results suggest this conclusion, because the researchers found in their research that special mental disorders associated with an increased infection rate of the herpes virus HHV-6. The viruses infect so-called Purkinje cells in the human cerebellum. These cells primarily provide motor learning and fine control of muscle tension and movement. In addition, they also influence feelings, perception, memory and language.

Surprising discovery

In the study, the research team examined patients with bipolar and major depressive disorders. It came to the surprising discovery. In the brains of the mentally ill, a high infection rate with the herpesvirus HHV-6 was found. Involved were the Purkinje cells, which affect, among other things, feelings and perception. "In patients with bipolar and major depressive disorders, we have been able to demonstrate an increased rate of active human herpesvirus infections predominantly in Purkinje cells of the human cerebellum," reports Dr. Bhupesh Prusty, group leader at the Department of Microbiology, in a press release on the study results.

Herpesviruses as new risk factor for depression?

"It has long been recognized that hereditary factors increase the risk of developing various types of psychiatric disorders, such as bipolar disorder, major depression and schizophrenia," said Drs. Prusty. In addition, there are always indications that environmental factors can play a role in the development. Viruses are such an environmental factor, the virus expert explains.

How do herpes viruses affect our brain??

"Viruses can disrupt the development of nerve cells and interfere with the interaction with the immune system in important stages of development," explains the virologist. Although most infections would initially pass without a trace, the viruses could persist in various organs and tissues and become active again after years. The central nervous system and the salivary glands are also places where the viruses settle, said Prusty.

Increased infection rate in depression and bipolar disorder

The team around Prusty found strong evidence that herpesviruses of type HHV-6A and HHV-6B play a key role in causing depression and bipolar disorder. The scientists analyzed two of the largest brain biopsy cohorts of the Stanley Medical Research Institute in the US and actually found the first scientific evidence. Patients with depression or bipolar disorder had an increased rate of active human herpesvirus infections in Purkinje cells.

Have dormant viruses been underestimated??

So far, scientists have assumed that viruses that "dormant" unrecognized in organs and tissues can never be responsible for a disease. "Studies, such as our current ones, prove that this thinking is wrong," sums up Prusty. He also refers to another study that has recently found a link between herpes viruses and Alzheimer's. These studies suggest that a rethinking of the role of viruses is needed. (Vb)