Components of identity expression in problem and non-problem gamblers.

Few studies have examined whether specific aspects of group identification predict problematic and non-problematic addictive behaviours and none have focused on gambling. Applying Leach et al.'s (2008) hierarchical model of in-group identification, we tested the associations between components of self-investment (satisfaction, solidarity, and centrality) and components of self-definition (individual self-stereotyping, in-group homogeneity) on distinguishing between problem and non-problem gambling (n = 10,157) and on the severity of problematic gambling behaviour (n = 2,568). Results showed that (i) in-group-based identities are important in predicting problematic vs. non-problematic gambling behaviours; (ii) in-group-based identities are important in predicting the severity of problematic gambling; (iii) how self-invested an individual is with their in-group and aspects associated with self-definition processes are both important predictors; (iv) perceptions related to how chronically salient one's group membership is for the self (centrality) are essential features of the self-investment mechanism; and (v) self-stereotypical beliefs about one's essential similarities to the prototypical gambling group member norm are fundamental for the defining oneself as a gambler.