Differentiating Non-Suicidal Self-Injury and Risky Drinking: a Role for Outcome Expectancies and Self-Efficacy Beliefs

Social cognitive theory articulates a role for two key thought processes in governing volitional behaviour: outcome expectancies and self-efficacy expectancies. These cognitions are behaviour-specific, and should thus differentiate people who engage in one behaviour over another. This paper presents the results of a study applying social cognitive theory to explore how outcome expectancies and self-efficacy expectancies differentially relate to non-suicidal self-injury (NSSI) and risky alcohol use amongst a sample of young adults. A sample of 389 undergraduate students completed self-report questionnaires assessing their engagement in NSSI, alcohol consumption, their beliefs about the anticipated consequences of self-injury and alcohol consumption (outcome expectancies), and their belief in their ability to resist self-injury or risky drinking (resistance self-efficacy). Generally, people who self-injure rather than drink are characterised by a belief in the ability to resist drinking, coupled with stronger positive, and weaker negative, NSSI expectancies. People who self-injure are less likely to think alcohol reduces tension than people who do not self-injure. People who engaged in both NSSI and risky drinking report more anxiety than participants who engaged only in risky drinking and lowered ability to resist self-injury. Overall, the findings suggest that a unique combination of beliefs differentially predict NSSI and drinking. The pattern of results suggests potential avenues for future research to delineate why people engage in one behaviour rather than another and to inform future prevention and early intervention initiatives.