Prospective associations between somatic illness and mental illness from childhood to adulthood

The association between somatic illness and psychiatric illness is well established in adults but is less clear in childhood and adolescence. A cohort of over 700 randomly selected children in Upstate New York were studied from ages 1-10 years in 1975 to young adulthood in 1992. Psychiatric and physical health were assessed by means of follow-up youth and parent interviews at 8-, 2 1/2-, and 6-year intervals (in 1983, 1985-1986, and 1991-1993). Cross-sectional and longitudinal analyses investigated: 1) the consistency of the relation between physical illness and mental illness in childhood; 2) the specificity of major depressive disorder (MDD) in accounting for the relation; 3) the specificity of immunologically mediated medical disorders in this relation; and 4) whether this relation was attributable to risks associated with low socioeconomic status. Cross-sectionally, ill health was associated with increased risk of psychiatric disorders at all ages, with significant odds ratios (ORs) ranging from 1.76 to 3.26. In prospective analyses, ill health increased the risk of new-onset MDD at all ages (ORs = 2.05-4.48). MDD also predicted subsequent ill health, independent of prior health problems (ORs = 3.81 and 4.04). Relations were not attributable to familial socioeconomic status. Associations were particularly strong between MDD and medical disorders associated with alterations in immunologic factors (ORs = 1.83-6.41). Theories of common immune-mediated vulnerabilities to medical illness and depression are consistent with these associations.