A population-based study of atopic disorders and inflammatory markers in childhood before psychotic experiences in adolescence☆

OBJECTIVE Schizophrenia is associated with atopy and increased inflammatory markers. We report a population-based longitudinal study of the associations between childhood atopic disorders, subsequent serum inflammatory markers, interleukin 6 (IL-6) and C-reactive protein (CRP), and the risk of psychotic experiences (PEs). METHOD PEs were assessed at age 13 years (n=6785). Presence of clinician-diagnosed atopic disorders (asthma and eczema) was determined from parent-completed questionnaires at age 10 years (n=7814). Serum IL-6 and CRP were measured at age 9 years (n=5076). Logistic regression examined the association between (1) atopy and PEs, (2) inflammatory markers and PEs, and (3) mediating effects of inflammatory markers on the atopy-PEs association. Linear regression examined the association between atopy and inflammatory markers. Age, gender, social class, ethnicity and body mass index were included as potential confounders. RESULTS At age 10 years, about 14% of the sample was reported to have asthma, 12% eczema, and 7% both asthma and eczema. Compared with children with no atopy, risk of PEs at age 13 years was increased for all of these groups; adjusted odds ratios (95% CI) were, respectively, 1.39 (1.10-1.77), 1.33 (1.04-1.69), and 1.44 (1.06-1.94). Atopy was associated with increased serum IL-6 and CRP; however, this did not mediate association between atopy and PEs. Inflammatory markers were not associated with later PEs. CONCLUSION Childhood atopic disorders increase the risk of psychotic experiences in adolescence. Follow-up of these individuals will be useful to determine the effect of atopy and inflammation on different trajectories of early-life PEs.