This study proposes to collect a third wave of data in a continuing effort to advance the systematic investigation of the role of Social Support in the general Stressor Illness model. Previously we have collected two waves of data (at a one year interval) from a representative sample of adults (N=1100) in the Albany-Troy-Schenectady area of New York State. This design, which reinterviews the same respondents three years after the initial interview, will give us one year, two year and three year intervals in which to examine the causal patterns among the principal model variables. This three-wave panel design provides for substantial statistical reliabilitiy in the construction of casual models relating stressors and social support to illness (primarily depressed mood). The data will allow the examination of other measured variables for the concepts in the basic causal model. It will also permit specification of these causal models in terms of other social and personality variables which have been found meaningful in previous analyses (e.g., age, sex, marital status and self-esteem). The analysis of the data will rely principally on the use of structural equation modelling techniques to incorporate both unobserved and measured variables, to estimate equation and measurement errors and to identify any potential rciprocal effects among the unobserved variables (i.e., stressors, social support, illness). We will also use the technique of decomposition of effects in regression analysis to specify the direct and indirect effects of model variables on the ultimate dependent variable(s). Other non-linear, tabular analytic techniques will also be used. The ultimate objective of this proposal is to firmly establish a rigorous stressor-social support-illness model, specified for each meaningful segment of the age structure, sex roles, marital status an cohort-period variations. This research design represents a distinctly advanced step in examining the causal roles played by stressors and social support in the epidemiology of depression and other disorders.