[Smartphone apps as a new psychiatric treatment]. 
The number of smartphone apps for people with mental health issues is undergoing a dramatical growth in these years.  We review the available literature on the topic, discuss opportunities and theoretical considerations using smartphone apps in psychiatric treatment and provide an overview of approaches that are currently in progress in this field in Denmark.  In a systematic literature search we found four small clinical trials with positive results.  However, none of the studies were randomised controlled trials, and the results have to be interpreted with caution.