Behavioural dependence (BD) for gambling has traditionally been subsumed under the concept of 'problems': a hybrid construct that includes both indicators of BD, and adverse consequences (harm) arising from excessive time and money expenditure. Although progress has been made towards specific measurement of harm, dedicated measures of BD do not exist. Theory led us to expect that (1) dependence and harm are measurably distinct constructs, (2) harm mediates the relationship between dependence and wellbeing, and finally, that (3) separate measures should be more effective than a unidimensional problems measure in predicting wellbeing. Candidate BD items from six existing measures of gambling problems were extracted and evaluated with respect to DSM-5 criteria and content overlap, leading to 17 candidate items. This was further reduced to 8 items based on both item content and psychometric criteria, using data from an online panel of 1524 regular gamblers, with demographic characteristics similar to Australian population norms. Participants also completed measures of harm, problems, and subjective wellbeing. All three hypotheses were confirmed. BD was shown to be highly reliable and unidimensional, and measurably distinct from gambling harms. Harm mediated the negative relationship between BD and wellbeing. The harm + BD model yielded better predictions of personal wellbeing that a unidimensional, continuous problems measure-and explained about twice the variance of a simple contrast between problem and non-problem gamblers. We conclude that is psychometrically justified to specifically measure gambling BD, and this may be of particular use in theoretically-driven applications.
Keywords: Addiction; Behavioural dependence; Gambling; Psychometrics.