Life expectancy associated with specific mental disorders and the contribution of causes of death: a population-based study in the region of Catalonia

There is strong evidence that people with mental disorders have a premature mortality, with physical diseases, as well as suicide, accounting for it in large part. However, there is a lack of studies focused on common mental disorders in Southern Europe. This study aims to calculate the reduction in life expectancy for different mental disorders according to all-cause mortality and for specific causes of death using national registers from Catalonia (Spain). This population register-based study includes clinical information on all adults over 18 years of age using the Catalan public healthcare system from January 2005 to December 2016 (355,540 females and 182,529 males with mental disorders). Mental disorders were classified into eleven categories, and causes of death were grouped as natural and unnatural and then further divided into nine groups. For each disorder, the life-years lost were estimated for all-cause mortality and for each specific cause of death in males and females. All mental disorders showed a shorter remaining life expectancy after diagnosis than the reference population of the same age. The disorders associated with the largest reduction in life expectancy were alcohol and drug dependence and abuse, and schizophrenia. Natural causes and, to a lesser extent, suicide, were the predominant contributors to excess mortality for all types of mental disorders. Our findings suggest that mental disorders are associated with premature mortality in Catalonia. Furthermore, natural causes are the primary contributors to premature mortality, indicating the need for better management of medical conditions in this population.