Insulin-dependent diabetes mellitus (IDDM) is one of the most prevalent and serious health problems in youth. Even with careful treatment, IDDM can lead to serious cardiovascular and other major organ system complications. Treatment has focused primarily on adherence to a complex and difficult treatment regimen. Although many researchers have found that metabolic control and adherence are related to several psychosocial variables, causal relations have rarely been demonstrated and comprehensive causal models have not been developed. In a cross-sectional study, we used structural equation modeling to develop a preliminary causal model of the linkages among several important psychosocial variables and adherence and metabolic control in youth with IDDM. The major aim of the present proposal is to further develop and empirically test our preliminary causal model in a four-year longitudinal design, and to increase the amount of variance that is predicted by the model by including pertinent psychosocial variables that were not assessed in the preliminary study. The second aim of the proposal is to identify environmental factors that relate to poor health in a group of children (i.e., black females) who are at high risk for future cardiovascular and other major organ system complications. The third aim is to develop preliminary psychosocial intervention strategies for youth who are at high risk for poor control and future complications. These interventions will be based on the causal models developed during the first four years of the project. We plan to test the efficacy of these intervention strategies in future controlled comparative outcome studies.