Health professionals have long known that depression can be brought on by challenging life events such as the loss of a loved one, marital difficulties or job loss. Genes can play a role and neurochemical changes in the brain may also be important. It comes as a surprise to learn that infections could also be important in psychological depression.
Linking Infection in Denmark to Depression and Suicide:
Depression leading to suicide may be an unexpected risk associated with repeated infection. Danish epidemiologists examined the health records of more than 7 million people for 30 years. What they found is that people who have been hospitalized for the treatment of infection are 40 percent more likely to commit suicide.
Those who have been hospitalized for at least seven infections have a startling 300 percent greater risk of suicide. Even though suicide is uncommon, this association is significant. The connection with hospitalization and infection accounted for about 10 percent of the suicides that took place in Denmark during the decades under analysis.
An accompanying editorial suggests that inflammation triggered by an infection may affect the brain and lead to depression. Some pathogens, including HIV and toxoplasmosis, seem to have particular affinity for the nervous system. The editorialists suggest that people with depression or suicidal behavior may need to be screened and treated for such infections.
[JAMA Psychiatry, online aug. 10, 2016]
