Cognitive profile partly mediates allergy-associated decrease in mental health

Background There is a well-established link between allergies and mental health. While both atopic and food allergies are associated with increased levels of depression and anxiety, it is unclear what the mechanism behind this relationship is. Several theories touch upon potential psychological mechanisms, but until now putative cognitive mechanisms of the link between mental health and allergies have been unexplored. Methods We employed tablet-based deep cognitive phenotyping, and also recorded mental health, socio-economic status, and allergies in 533 children aged 7-9 years. We then employed mediation analyses to test whether cognitive mechanisms mediated the association between allergies and mental health. Findings In line with previous research, we found children with allergies reported higher levels of anxiety and depression. Furthermore, compared to children without allergies, they showed faster processing speed, equal verbal short-term memory, and worse performance on tests of fluid reasoning, number sense, search organisation, and spatial short-term memory. We confirmed that these variables predicted allergic state using logistic regression. Most importantly, we found that cognition partially mediated the relationship between allergy and both anxiety and depression. Interpretation Our results suggest that allergies bias children towards particular cognitive profiles, which in turn are risk factors for anxiety and depression. This supports the view that early cognitive interventions could reduce the number of allergic children that develops comorbid psychiatric conditions. Funding This study was supported by grant TWCF0159 from the Templeton World Charity Foundation to DEA, and by the UK Medical Research Council.