Facial emotion recognition deficits in abstinent cannabis dependent patients.

Cannabis is clearly the most popular illicit drug in North America, Europe and in other parts of the world. Evidence is accumulating for the involvement of the endocannabinoid system in emotional processing. However, only few studies examined emotional processing in chronic, heavy cannabis users and these studies were performed in cannabis dependent patients who were abstinent for 12-48 hours. The aim of this study was to investigate facial emotion identification and discrimination abilities in patients with cannabis dependence who were abstinent for at least 1 month.The study included 30 males with cannabis dependency according to DSM-IV criteria and who had been abstinent for at least 1 month and 30 healthy controls. All the subjects were evaluated with Facial Emotion Identification Test (FEIT) and Facial Emotion Discrimination Test (FEDT).The main finding of this study was the presence of deficits in both identification and discrimination of facial emotions in cannabis dependent patients during abstinence. In addition, when we examined negative and positive emotions separately, we found out that abstinent cannabis dependent patients performed significantly worse than controls in the identification of negative emotions but not positive emotions.Our findings indicate that facial emotion recognition deficits which have previously been observed in current cannabis users are still detectable in abstinent cannabis dependent patients and do not improve quickly with abstinence (an average of 3.2 months).