Effect of Ego Depletion on Interpersonal Trust among Individuals with Substance Use Disorders

Individuals with substance use disorders (SUD) undergo treatment to recover from addiction. However, exerting self-control, which is essential for successful abstinence from drug addiction, can cause ego depletion. This study experimentally investigated the effect of ego depletion on interpersonal trust and examined possible changes in the ego depletion effect across different abstinence periods. This study employed a 2 (ego depletion: high vs. low) × 2 (partners: non-SUD vs. SUD) mixed factorial design. The participants were 273 male individuals with SUD and with periods of drug abstinence ranging from several days to 2 years, who resided in a compulsory drug rehabilitation center. The participants were first asked to complete an ego depletion task, followed by a decision-making task in a trust game, first with a non-SUD stranger, and then with a SUD stranger. Ego depletion was not related to trust in non-SUD strangers. However, ego depleted participants were more likely to trust SUD strangers than non-ego depleted participants. Moreover, this ego depletion effect fluctuated near the end of SUD treatment. This study highlights the importance to ensure follow-up outpatient care and offer social support services for individuals with SUD after compulsory SUD treatment.