Aims: Accurate recognition of facial expressions of emotion is critical in interpersonal interaction but is impaired in alcoholics, even after a period of abstinence. Little is known of whether other drug-dependent populations also show these impairments. This study aimed to investigate facial expression recognition by chronic opiate users.
Design: An independent group design was used to compare 20 participants receiving opiate substitution treatment, 20 ex-opiate users in rehabilitation (average abstinence of 6 months) and 21 unemployed healthy controls.
Measurements: The accuracy and speed of recognizing morphed emotional facial expressions were assessed using an emotional hexagon task.
Findings: Current opiate users were significantly more accurate than ex-users at recognizing expressions of disgust. They were also generally slower than controls in recognizing all expressions, and slower than ex-opiate users in recognizing surprise, happy and fearful expressions.
Conclusions: Opiate users in maintenance treatment show a heightened ability to recognize facial expressions of disgust. We suggest that this may reflect increased exposure to other people's expressions of disgust and/or priming by the physical and social environments encountered by opiate-dependent individuals. Further, opiate maintained individuals' global slowness in processing emotional expressions may reflect the sedative effects of methadone.