There exists a comorbidity between atopy and schizophrenia.

A new study published in Frontiers in Psychiatry examined the probable association between atopic disorders—eczema, allergic rhinitis and asthma, and nonclinical psychotic experiences.

This was a large cross-sectional, observational population-based study that evaluated psychotic experiences in a Dutch population sample through an online survey. Overall, 6,479 participants – 14 years of age or above, filled out the Questionnaire for Psychotic Experiences, together with questions screening for atopic disorders—eczema, allergic rhinitis and asthma. Prevalence rates were calculated; odds ratios (ORs) was determined – age, gender and years of education as covariates.

The findings revealed that individuals diagnosed with one or more atopic disorders had an increased risk of psychotic experiences as compared to controls. Analysis of individual symptoms showed an OR of 1.27 for hallucinations while delusions only showed a trend. With each additional atopic disorder, the risk of psychotic experiences increased. This was observed for hallucinations alone, but not for delusions alone. Furthermore, atopy was associated with hallucinations across all modalities. The results did not appear to be driven specifically by any one atopic disorder. 

It was inferred that atopic disorders—asthma, eczema and allergic rhinitis, increase the risk of psychotic experiences in a dose-response manner. The results indicated the role of immunological components in the predisposition for psychosis.