This is an ongoing, longitudinal study of 8-to-13 year-old children with insulin-dependent diabetes mellitus (IDDM) who have been followed since the IDDM was diagnosed. The project continuation will assure: (a) a minimum of 5-year follow-up on all Ss, (b) follow-up of up to 10-years on early recruits (thus, some Ss will be studied up to late adolescence/early adulthood), and (c) time to analyze fully our extensive data base. The study's objectives include the following: (a) establish the incidence of depression as an initial response to/later sequela of IDDM, (b) test the hypothesis that an initial depressive reaction is akin to """"""""mourning"""""""" and a good prognosticator of later adjustment, (c) examine over time the interface of psychosocial and medical variables, (d) delineate the characteristics of coping, (e) delineate predictors of poor """"""""metabolic control"""""""", (f) test the hypothesis that adolescents have """"""""unique"""""""" problems, increased psychiatric illness and worsening of metabolic control, (g) examine precursers of adolescent adjustment and medical status, and (h) delineate the psychologic/functional impact of the onset of diabetic complications. The project entails a repeated assessment design with 95 newly diagnosed juvenile diabetics and their parents. Ss and their parents are evaluated via a broad-based, standardized test battery to assure reliable and valid data, and replications. Diverse variables are assessed; e.g., clinical/psychiatric symptoms, attitude toward IDDM, social and educational functioning, familial parameters. Both clinician- and self-rated scales are used. Medical and all salient outcome variables are assessed independently. The study will provide guidelines to medical staff as to the longitudinal characteristics and process of coping with IDDM among children, adolescents, and their parents, and young adults. Identification of risk rates and correlates of psychiatric illness, including depression, may facilitate early intervention. Delineation of the interface of psychosocial and medical variables may clarify unresolved issues in the field and provide data for clinical management, psychosocial intervention, and patient education.