Childhood asthma, eczema linked to adolescent psychotic experiences

UK research indicates that children with asthma and eczema are significantly more likely to have psychotic experiences during adolescence, boosting a previously reported relationship between schizophrenia and atopic disorders.

Golam Khandaker (University of Cambridge) and colleagues studied data on 7814 children who were followed up from birth to the age of 10 years. During this time, 14.4% were physician-diagnosed with asthma, 12.7% with eczema, and 7.3% with both asthma and eczema.

Among 6784 of the children who were interviewed at age 13 years, 14.2%, 15.2%, and 16.0% of those with eczema, asthma, and both conditions, respectively, had had psychotic experiences in the previous 6 months compared with 11.7% among those with no atopy.

This equated to a respective 33%, 37%, and 44% increased odds for psychotic experiences compared with those with no childhood atopy, after adjustment for confounders such as gender, socioeconomic status, and ethnicity.

Using available data on 3850 children, the team found that those with atopy had significantly higher levels of interleukin (IL)-6 and C-reactive protein at age 9 years than children without. However, this did not appear to mediate the association between atopy and psychotic experiences, and levels of the markers were not associated with the risk for psychotic experiences.

Khandaker and colleagues say that the findings are in line with previous reports of increased asthma prevalence among adult patients with schizophrenia and an increased risk for developing schizophrenia over time in individuals with atopic conditions.

They note that their failure to find an association between psychotic episodes and levels of IL-6, a purported state marker of acute psychosis, may be due to methodologic errors and should be explored more comprehensively in future studies.

Writing in Schizophrenia Research, the researchers explain that the effect of inflammatory cytokines on the developing brain has been suggested as a potential mechanism linking early-life infection to schizophrenia. The team also suggests that a common genetic pathway may underlie both atopy and schizophrenia.

“[I]t is possible that atopic conditions, in the presence of pre-existing genetic liability, can lead to a distinct or pathological immune response,” they write.

“In turn, this may lead to [central nervous system] alterations making these individuals susceptible to developing psychotic illness in adult life.”

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