The purpose of this project is to identify and later modify psychosocial factors associated with nonadherence to diabetic regimens. Type I (insulin dependent) diabetics between 12 and 55 years of age and their families will serve as subjects in the project. An initial study will identify social learning factors that are predictive of adherence to several different aspects of diabetic regimens (insulin administration, urine testing, diet, and exercise). Structured interviews will be conducted with patients and their families to assess predictor variables (e.g., self-efficacy, health locus of control, self-control behaviors, perceived barriers to adherence, and degree of family support). Subjects will be stratified according to age and then randomly assigned to one of two conditions to assess the possible reactive effects of repeated testing on adherence to regimen and diabetic control. For half of the participants, interviews will be conducted initially and at a 6 month follow-up. The remaining participants will be assessed at 2 month and 4 month intervals in addition to the initial and final meetings. Measures of compliance will include recently developed self-report scales and week-long self-monitoring records. Measures of control will include blood glucose levels, 24 hour urine tests, A1C hemoglobin levels, and HDL cholesterol assessments. Psychosocial variables identified as predictors of adherence in the first study will provide the basis for later intervention studies. Within-subject, multiple baseline designs will be employed to develop cost-effective, individualized behavior therapy programs for improving adherence. Finally, we will conduct pilot work for a randomized trial to determine the relative efficacy and cost-effectiveness of a) health education, b) self-monitoring and goal setting, and c) a multifaceted behavioral treatment program.