Based on a new psychopathological model of adjustment disorders (AJD), we propose that AJDs are particular forms of stress response syndromes, in which intrusions, avoidance of reminders, and failure to adapt are core symptoms. We aim to demonstrate that these AJD symptom groups constitute a disorder that is distinct from posttraumatic stress disorder (PTSD), complicated grief disorder, major depressive disorder, and subsyndromal depression, by estimating their prevalence and comorbidities. A representative sample of elderly persons from Zurich, aged 65 to 96 years, was assessed by standardized interviews or self-report questionnaires. Index events for AJD were indicated by 52% of the sample set, with a 2.3% current prevalence of AJD. Prevalence rates for other disorders were 0.7% PTSD, 4.2% subsyndromal PTSD, 4.2% complicated grief disorder, 2.3% major depressive disorder, and 9.3% subsyndromal depression. The comorbidity rate for AJD and other Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition disorders is 46%, and that between AJD and subsyndromal disorders is 38%. Use of mental health care for AJD is low. This article concludes that the new concept of AJD constitutes a meaningful psychopathological model and thus warrants a place in standardized psychiatric taxonomies. Although this study was restricted to a sample of the elderly, it provides evidence regarding AJD prevalence, comorbidity, and associated health care use, all of which indicate its utility.