A study of the “three A’s” - common allergic diseases - shows that individuals with these diseases are also at an increased risk of psychiatric disorders. This connection likely stems from inflammation and psychological stress, and scientists from the Tri-Service General Hospital in Taiwan hope that medical professionals will take heed.
The present study is the first to identify a link between three common allergies, the “three A’s” - also known as asthma, allergic rhinitis (or hay fever), and atopic dermatitis (or eczema), and a risk of developing psychiatric disorders. Specifically, researchers found that people with these allergic conditions are 1.66 times more likely to develop a psychiatric disorder.
The query started when one researcher, lead author Dr. Nian-Sheng Tzeng, noticed that patients with one of the three A’s were also suffering emotionally. Tzeng wanted to “clarify whether these allergic diseases are associated with psychiatric disorders.”
Tzeng and others conducted a review of the literature surrounding allergic diseases and psychiatric and emotional disorders. Some studies described connections between the two conditions, but not all findings contained supportive evidence. Tzeng decided to look specifically at the three A’s and their connection to the overall risk of psychiatric disorders.
The study contained health information from a health insurance claims database from people of all ages in Taiwan, ranging over 15 years. There were 46,647 people with allergic diseases, and 139,941 people with no allergic disease. Researchers found that 10.8 percent of people with allergic diseases developed psychiatric disorders during the study timeline, but only 6.7 percent of people without allergic disease developed such disorders.
Asthma and hay fever, but not atopic dermatitis, posed a particularly high risk for psychiatric disorders. Additionally, using certain asthma medications lowered the risk.
What is the basis behind the connection? Researchers theorize that a large role is played by inflammation, which is linked to many disorders (psychiatric, depression, anxiety, allergies). Psychological stress could also be a factor.
Further studies need to be done to conclusively assess the cause of the link between allergic diseases and psychiatric disorders, but for now, Tzeng and others want to at least let medical professionals know about the connection.
"We would like to let clinicians who care for patients with allergic diseases know that their risk for psychiatric diseases may be higher," Tzeng said. "Assessing their emotional condition and monitoring their mental health could help to avoid later psychiatric problems."
The present study was published in the journal Frontiers in Psychiatry.