Altered neural processing of social reward in male heroin abstainers.

Individuals who are addicted to drugs often face unfavourable social conditions and difficulty with social adaptation. Both may be closely related to impaired social cognitive ability. This study posits that social cognitive impairments likely arise from blunted social reward processing in drug users. This study aimed to explore the electrophysiological mechanism of social reward processing in people who abstain from using heroin (heroin abstainers). Twenty-eight male heroin abstainers and 27 matched controls completed the social incentive delay task. At the same time, their corresponding behaviour and electroencephalography data were recorded. The feedback-related negativity (FRN) elicited by positive outcomes was significantly more positive than that elicited by negative outcomes for the healthy controls. However, no significant difference in FRN was found between negative and positive outcomes among the heroin abstainers. There was no significant difference in P3 (a positive event-related potential component after FRN) elicited by negative and neutral outcomes in the heroin abstainers. Meanwhile, negative outcomes elicited greater P3 than neutral outcomes in the healthy controls. In addition, this study also found that withdrawal time was negatively correlated with the difference wave of FRN for the heroin abstainers. Heroin abstainers may be hyposensitive to the processing of social reward outcomes. In other words, they may have insufficient motivation to acquire social rewards. Abnormal social reward processing found in heroin abstainers can be improved with an increase in abstinence time. These results deepen our understanding of the social reward impairments associated with chronic drug use.