Study: Viruses are involved in the development of mental illnesses
Herpes is extremely common. Once you are infected with the virus, you will never get rid of it. It slumbers to break out again and again in the form of annoying bubbles. A German-American team of researchers found a connection between herpes viruses and the development of mental illnesses such as depression, bipolar disorders and schizophrenia. According to the scientists, the viruses disrupt the development of nerve cells and impede the immune system at important stages of development.
Researchers from the Institute of Virology and Immunobiology at the University of Würzburg, together with American colleagues from the Stanley Medical Research Institute, recently provided new information on the development of mental illnesses: The human herpes virus HHV-6 can infect nerve cells and thus possibly cause cognitive disorders. These disorders could be the cause of depression and bipolar disorders. The study results were recently published in the specialist journal "Frontiers in Microbiology".
Can viruses trigger mental illness?
According to the current study results, this conclusion is obvious, because the researchers found in their investigations that special mental disorders are 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 movements. In addition, they also influence feelings, perception, memory and language.
In the study, the research team examined patients with bipolar and severe depressive disorders. This led to the surprising discovery. A high infection rate with the herpes virus HHV-6 was found in the brains of the mentally ill. The Purkinje cells were affected, which also affect feelings and perception. "In patients with bipolar and severe depressive disorders, we were able to demonstrate an increased rate of active infections with human herpes viruses primarily in Purkinje cells of the human cerebellum," reports Dr. Bhupesh Prusty, group leader at the chair of microbiology, in a press release on the study results.
Herpes viruses as a new risk factor for depression?
"It has long been known that hereditary factors increase the risk of developing various types of psychiatric disorders such as bipolar disorders, severe depression and schizophrenia," said Dr. Prusty. In addition, there are always indications that environmental factors can play a role in the development. Viruses would be such an environmental factor, explains the virus expert.
How do herpes viruses affect our brain?
"Viruses can disrupt the development of nerve cells and hinder interaction with the immune system at important stages of development," explains the virologist. Most infections would initially pass without a trace, but the viruses could persist in various organs and tissues and become active again after years. The central nervous system and salivary glands are also places where the viruses nest, according to Prusty.
Increased infection rate for depression and bipolar disorder
Prusty's team found strong evidence that herpes viruses of the HHV-6A and HHV-6B types play a key role in the development of depression and bipolar disorders. The scientists analyzed two of the largest brain biopsy cohorts from the Stanley Medical Research Institute in the United States and actually found the first scientific evidence. Patients with depression or bipolar disorder had an increased rate of active infection with human herpes viruses in Purkinje cells.
Have dormant viruses been underestimated?
So far, there has been an assumption in science that viruses that "sleep" undetected in organs and tissues can never be responsible for a disease. "Studies like our current one prove that this thinking is wrong," summarizes Prusty. He also refers to another study that recently found a link between herpes viruses and Alzheimer's. These studies suggest that it is necessary to rethink the role of viruses. (vb)