RESULTS: The risk of psychiatric morbidity in children with type 1 diabetes compared with the general population was tripled within 6 months after the onset of diabetes (hazard ratio [HR] 3.0 [95% CI 2.7-3.4]) and doubled within the total observation period (HR 2.1 [95% CI 2.0-2.2]). An increased risk was noted in suicide attempts (HR 1.7 [95% CI 1.4-2.0]) and in most categories of psychiatric disorders. The risk of psychiatric disorders in probands declined from HR 2.7 (95% CI 2.2-3.3) for those in the cohort born 1973-1986 to 1.9 (95% CI 1.8-2.0) in those born 1997-2009. The risk for any psychiatric disorders among siblings of patients with type 1 diabetes was estimated to be HR 1.1 (95% CI 1.0-1.1), and there was no increased risk in any of the specific category of disorders.