PSYCHOPATHOLOGY AS A PREDICTOR OF DISABILITY - A POPULATION-BASED FOLLOW-UP-STUDY IN BALTIMORE, MARYLAND

To determine whether psychopathology is associated with disability as a result of underlying physical illness or whether such psychopatholog y antedates disability and is an independent determinant of disability , the authors conducted a nested case-control study within the Epidemi ologic Catchment Area Follow-up Study in Baltimore, Maryland. From a 1 981 random sample of 3,481 persons from Baltimore interviewed for psyc hopathology, disability, and other comorbidity, 1,920 who were alive i n 1993 were traced and were reinterviewed with a similar instrument, W ithin the study population, 168 new cases of disability were identifie d as occurring between 1981 and 1993, as measured by the inability to perform activities of daily living. These cases were compared with 1,7 15 controls who reported no disability. The sociodemographic factors t hat were significantly related to incident disability in this analysis were age, female gender, and less than a high school education. These comparisons revealed associations of incident disability in activitie s of daily living with almost all antecedent chronic physical illnesse s. Significant age- and gender-adjusted associations were observed bet ween incident disability in activities of daily living and antecedent (in 1981) alcohol abuse and dependence (odds ratio (OR) = 2.5, 95% con fidence interval (CI) 1.5-4.2), major depressive disorder (OR = 4,2, 9 5% CI 2.2-8.3), and phobia (OR = 1.9, 95% CI 1.3-2.8), The adjusted od ds ratio for the joint effect of antecedent depression and chronic phy sical illness on incident disability in activities of daily living was 17.0 (95% CI 6.9-41.7). There was a significant independent effect of antecedent major depression on activities of daily living disability. The effect of psychopathology on incident disability is nonspecific a s to type of baseline chronic physical illness. Such a finding has imp ortant implications for defining strategies to prevent disability. Am J Epidemiol 1998;148:269-75.