Abstract
BACKGROUND: Interpersonal trust is an important target for the conceptualization, identification, and treatment of psychiatric disorders marked by interpersonal difficulties. A core feature of adolescent externalising disorders is interpersonal impairment. However, research investigating trust is scarce. A relatively novel approach for studying trust in psychopathology is through examination of social decision making using behavioural economic games. OBJECTIVE: To employ a modified trust game in order to determine whether externalising adolescents exhibit perturbed decision making in social and/or nonsocial contexts. METHODS: Externalising inpatient adolescents (n = 141) and non-externalising psychiatric controls (n = 122) completed self-report measures of psychopathology and invested in an iterative trust game played under two conditions: social (trust) and nonsocial (lottery condition), each consisting of five consecutive trials. RESULTS: Externalising adolescents showed a limited increase in trust investments, compared to a significant increase in lottery investments, across early game trials relative to psychiatric controls. This significant three-way interaction between experimental group, game condition, and trials became most evident at the second trial of games. Between-group differences on trust investments were non-significant. However, externalising adolescents invested significantly less in the trust relative to lottery condition, an effect unobserved in psychiatric controls. CONCLUSIONS: This study tentatively suggests that adolescent externalising disorders may be associated with an insensitivity to normative social exchange which may arise, in part, from a lack of anticipated co-player reciprocity. It is not the level of trust that may distinguish externalising adolescents but perhaps the form of which the trust exchange takes shape. Conclusions are tempered by the fact that the employed trust game did not include feedback in the form of co-player repayments.