[Mental Health apps: innovations and challenges].

Apps are widely used worlwide and are candidate for a growing role as mobile and digital health support services. Their ubiquitous characteristics and their wide dissemination make this technology particularly appealing for psychiatry and addiction medicine. Apps allow for ecological momentary assessment and intervention. It is hypothezised they are able to reach people, to engage them in app related services and to promote behavior change and empowerment. It seems that apps could reach target populations. Sustainable engagement is however still challenging for most of them. Some specific apps are possibly able to promote a given behavior in a specific population.