Diseases such as bronchial asthma and eczema, scientists have associated with the risk of depression, anxiety, schizophrenia, bipolar disorder. Evidence suggests that this risk increases with severe allergies. There is a theory that the increased level of inflammation in allergies may contribute to the occurrence of mental disorders.
However, it remained unknown whether allergies and associated inflammation are a causative factor in psychiatric disorders. The fact is that the studies that were carried out could only show the connection between these problems. In a new study, scientists have tried to solve this problem.
Scientists at the University of Bristol analyzed data from the British Biobank, a long-term study that collected genetic data from approximately 500,000 volunteers. Using conventional epidemiological research methods, they, like the authors of previous studies, found a significant relationship between diagnoses of allergic and mental illness. Then the scientists applied genetic analysis methods.
The authors of the study found out which of the Biobank participants had genes that predispose to allergies or mental disorders. Then they checked how often the other develops against the background of the genetic risk of one of these conditions. This research method is called Mendelian randomization. It is believed that the data obtained in this way allows scientists to draw conclusions about the causal relationship between diseases.
Mendelian randomization showed that allergies are unlikely to be the cause of mental illness, and mental health problems are not the cause of allergies.
One of the findings of the research is that allergy prevention, while a very important task in itself, is unlikely to help reduce the prevalence of mental disorders.