Pathologies duelles et polyconsommation sont fréquemment associées et rendent difficiles un diagnostic catégoriel et des soins spécifiques. La déconstruction du tableau clinique en dimensions fonctionnelles et en endophénotypes permet de proposer un traitement pragmatique adapté aux besoins, aux ressources et à l’écologie du patient via une pharmacopsychothérapie incluant : (1) des stratégies substitutives de réduction des risques et des dommages (modalité de consommation, produit, comportement) ; (2) une combinaison graduée de psychothérapies (approche de réhabilitation psychosociale) et ; (3) une pharmacologie dimensionnelle (dimensions élémentaires et endophénotypes) et un traitement spécifique lorsque le diagnostic catégoriel est possible. Cette approche intégrative permet de traiter en ambulatoire les patients les plus complexes.

Dual disorders are common and polydrug use is the norm. In patients combining both, the clinical presentation results from a mixture that makes a categorical diagnosis as well as a specific and stepped care difficult to establish. However complex the clinical picture, its deconstruction by elementary functional dimensions and endophenotypes (e.g. impulsivity) allows for pragmatic, gradual and integrative holistic treatment suited to the patient's needs, resources and ecology. There are currently no validated strategies in the literature. According to our experience and the Research Domain Criteria approach, we propose a framework that provides functional understanding (drug's functions in the psychic economy) and treatment of addictions which are considered to be dysfunctional adaptive strategies. Motivation- and education-based treatment aims at restoring functional autonomy and quality of life in accordance with the patient's needs, and combines dimensional pharmacopsychotherapy, including: (1) substitutive strategies of harm reduction: substitution of consumption modalities and/or substances and/or behaviours (e.g. how to cope differently, starting from strategies applied by the patients and reinforcing what intuitively better works for them); (2) an integrative psychotherapy based on psychosocial rehabilitation modalities and introduced gradually, to first address the most basic functions (life rhythms, negative emotions, etc) then the more and more complex issues (social processes, cognitions) and; (3) a behavioral pharmacology according to medication's mechanism of action (neuroscience-based nomenclature) allowing for treatment of elementary dimensions and endophenotypes, complemented by specific treatments when categorical diagnosis is possible. In our experience, such an integrative approach allows for efficient treatment of the most complex patients in an outpatient setting.