Isolated death (ID) (i.e., dying alone without anyone noticing for several days) has been suggested to be related to social isolation, mental disorder, and alcohol and/or drug abuse. A major transfer of patients with a mental disorder and/or alcohol and/or drug abuse from institutionalized care to treatment as outpatients has been enacted in Sweden during the past decade. On the basis of the assumption that such deinstitutionalization is likely to result in increased social isolation, our working hypothesis was that the incidence of ID among patients belonging to these categories has increased in Sweden. The present study involved all deaths subjected to a medicolegal examination in Stockholm County (with a population of approximately 1.9 million people) during the period 1992–2000. The pattern of ID (defined as cases involving a postmortem delay between death and discovery of at least 1 week), as well as the incidence of fatalities subjected to medicolegal examination with a record of mental disorder and/or alcohol and/or drug abuse was evaluated. Throughout this period, the proportion of the deceased with a record of a mental disorder was high among all the cases examined and higher still among the cases of ID, especially among those younger than 65 years of age. There was a rather limited increase in the incidence of ID and a much more pronounced increase in the number of former psychiatric patients whose deaths were subjected to medicolegal examination, but did not satisfy the criteria for ID. A record of alcohol and/or drug abuse was more common than a diagnosis of mental disorder among both the males and females who died at an age of less than 65, with a clear difference between the cases of ID and non-ID in the case of men. There was no significant increase in incidence over the course of this study. Thus, this study reveals a slight increase in the number of IDs and a more pronounced increase in the number of medicolegal examination of non-IDs of individuals with a record of a mental disorder.