health professionals have long known that depression can be triggered by the challenge life events such as the loss of a loved one, marital problems or job loss. Genes may play a role and neurochemical changes in the brain may also be important. It comes as a surprise to learn that infections may also be important in psychological depression.
Linking infection in Denmark for depression and suicide:
The depression that leads to suicide may be an unexpected risk associated with repeated infections. Danish epidemiologists examined the medical records of more than 7 million people for 30 years. What they found is that people who have been hospitalized for treatment of infection are 40 percent more likely to commit suicide.
Those who have been hospitalized for at least seven infections have an astonishing 300 percent increased risk of suicide. Although suicide is rare, this association is significant. The connection with hospitalization and infection account for about 10 percent of suicides in Denmark during the decades under analysis.
In an editorial suggests that inflammation caused by an infection can affect the brain and lead to depression. Some pathogens, such as HIV and toxoplasmosis, seem to have a particular affinity for the nervous system. The editorialists suggest that people with depression or suicidal behavior may need to be examined and treated for such infections.
[JAMA Psychiatry, online aug. 10, 2016]