Are allergies linked to depression?

Do allergies play a role in depression? A new study suggests that depressed people who are allergic to pollen are more likely to experience a worsening of their symptoms during allergy season.

Partam Manalai of the University of Maryland School of Medicine in Baltimore and colleagues studied 100 volunteers who had been previously diagnosed as suffering from depression. The researchers assessed their mood during allergy season and compared it to another part of the year. They also took blood samples.

In a report being presented this week at the American Psychiatric Association's annual meeting in New Orleans, Manalai reported that the subjects' depression worsened when they were suffering from the stuffiness, sneezing and coughing caused by their allergies. But even those who did not have symptoms, but whose blood samples showed their immune systems were responding to pollen experienced more depression.

The findings indicate that allergies can make depression worse in those who suffer from both conditions. It's the first time that's been shown. While more research is needed to understand how allergies may make depression worse, the findings also indicate that treating a depressed person's allergies may help improve their mood, even if they aren't actually experiencing symptoms of an allergic reaction.

The findings are important, the researchers say, because half of people are estimated to suffer from allergies, including about one in five who are believed to be allergic to pollen. The results also fit with previous research that has shown an increase in suicides during the spring and fall allergy seasons.