Longitudinal findings from the normative aging study: 1. Does mental health change with age?

Longitudinal changes in self-reported symptoms were investigated using the Cornell Medical Index (CMI) in a sample of 2,041 men. The average man completed 5 CMIs (range = 2-8) over 17 (range = 2-25) years. Using a two-stage growth model, we first regressed symptoms against time on study for each man. The average slope of physical symptoms showed a moderate increase over time, but the average slope of psychological symptoms showed little change. Next, individual differences in change were examined using age at entry as an explanatory variable. Age accounted for 50% of the variance in physical symptoms at entry and 7% of the variance in slopes, but explained neither baseline level nor change in psychological symptoms. Rather, a U-shaped curve described the relation between age and psychological symptom change. These results, in concert with a developmental perspective, may help reconcile conflicting findings on aging and mental health.