Infections and autoimmune disorders can take their toll on your physical wellness, but now Danish researchers have found that these disorders can affect other aspects of your wellbeing. According to their new study, published June 12th in the journal JAMA Psychiatry, infections and autoimmune disorders may increase your risk of developing mental health problems, such as depression, later in life.
Of the three million people who were involved in the study, those who were hospitalised for infections were 62% more likely to go on to develop a mood disorder than with people not hospitalised for infections. Likewise, those who were hospitalised for an autoimmune disease – which occur when your immune system goes awry and attacks your body’s own cells or tissues – were 45% more likely to subsequently develop a mood disorder.
The study included people born in Denmark between 1945 and 1996 who were followed until the end of 2010. The results also revealed a correlation between risk of mood disorder and the number of times a person was hospitalised. Compared to those who weren’t hospitalised for an infection, those who were hospitalised three times with infections during the study had double the risk of a mood disorder, and those who were hospitalised seven times had triple the risk.
Scientists hypothesise that the inflammation that infections or autoimmune disease bring may affect your brain in a way that raises your risk of mood disorders, and the new study supports this theory. The researchers commented that they estimate infections could be responsible for up to 12% of mood disorders, but the link first needs to be confirmed in further studies. However, it’s important to bear in mind that, at this point, only an association has been found.
According to Ian Gotlib, a professor of psychology at Stanford University, who was not involved in the study, the researchers were unable to prove that infections or autoimmune diseases are the cause of mood disorders, as other factors may explain the link, such as stress or the experience of hospitalisation. He added that the study was “impressive” and raised important questions, but future studies need to untangle whether infections are really the cause of mood disorders, or if the two just happen to occur together.