Book excerpt: The study of addiction draws primarily on methods and approaches to understanding, treating and supporting addiction drawn from traditional approaches. The foundations of which focus on responses seen across groups, but often neglecting to account for the role the individual differences plays in understanding and treating addiction. It is clear from the literature that there is often a lack of consensus in both understanding and treating those struggling with addiction. Individual differences therefore, whilst not always conforming to the accepted model for developing theoretical interpretations and practice in the field, are key to successful outcomes in treating addiction.