There likely is no causal effect of allergic disease on mental health, according to a study published online Oct. 5 in Clinical & Experimental Allergy.

Ashley Budu-Aggrey, Ph.D., from the University of Bristol in the United Kingdom, and colleagues used Mendelian randomization (MR) to investigate a possible causal relationship between atopic disease and mental health phenotypes.

The researchers found strong evidence of an association between the broad allergic disease phenotype and self-reported depression (odds ratio, 1.45), anxiety (odds ratio, 1.25), bipolar disorder (odds ratio, 1.29), and neuroticism (β = 0.38). Similar associations were seen for asthma, atopic dermatitis, and hayfever with the mental health phenotypes, although weaker associations were seen for atopic dermatitis and hayfever with bipolar disorder. For either direction, there was little evidence of causality.

"Few of the observed associations between allergic disease and mental health were replicated. The causal effect we did identify appears to be much lower in magnitude than that suggested observationally," the authors write. "Therefore, intervening to prevent onset of allergic disease is unlikely to directly prevent the onset of mental ill-health. But future work should aim to investigate whether interventions that aim to improve allergic disease have a causal effect on mental health (and vice versa)."

One author disclosed financial ties to the pharmaceutical industry.

Abstract/Full Text