[Affective disorders: analysis of their comorbidity in the more frequent psychiatric disorders]

Comorbidity is defined as the presence of two or more independent diseases in the same subject. This paper reviews the comorbidity of affective disorders with other mental disorders. We focus on the disorders of anxiety, schizophrenia, dependence on psychoactive substances, eating disorders, personality disorders and obsessive-compulsive disorder. To this end, we have carried out an extensive review that has taken account of numerous studies, as well as of different diagnostic orientations (categorical or dimensional). In general the presence of affective symptoms and/or disorders in the context of other mental pathologies is high. Moreover, comorbidity has a high transcendence with respect to clinical prognosis (worse response to treatments, greater symptomatic persistence, greater tendency to chronicity and greater risk of mortality) and the social consequences (decline in work performance and greater use of resources). Nonetheless, we must bear in mind that the analysis of the comorbidity of affective disorders in other mental disorders is complex and controversial, not only because of its high frequency, but also because of the existence of symptomatic overlap, scarcity of signs and pathognomonic symptoms, variability of diagnostic criteria, applied methodological differences, as well as a scarcity of longitudinal and prospective studies.