[Severe depression and addictions].

Addictive co-morbidities (or co-occurrent disorder, double diagnosis, associated diagnosis) associated with depression are diagnoses which must be made independently and not only seen as a cluster as symptoms of the disorder or as disorders induced by taking the toxin. The association of an addictive disorder with depression raises a prognostic problem as this association results not only in mutual worsening of the two disorders but in a further problem of penalising access to care with an important sub-diagnosis. This is a common association ; however as 30 to 50% of patients admitted to psychiatric units in Europe have a mental disorder combined with substance abuse (alcohol, sedatives, cannabis). In this article we describe the different findings reported in the literature showing how this association is strong and may have consequences in terms of delayed diagnosis and prognostic and therapeutic impact. We also show that regardless of the origin of the association (attempted self-medication, addiction-induced depression, consequence of depression or a fortuitous association), dual psychiatric and addiction medicine practice is always justified even if this is frequently complex because of the ways in which the different facilities available to us operate in isolation.