An early BN study proposed that increased purging behaviours were correlated with increased psychological disturbances and decreased compulsive control and may constitute a sub-type, multi-impulsive bulimia (Lacey & Evans 1986). Tobin et al. (1992) indicate 80% of people experiencing BN engage in purging behaviours, 16% vomiting alone, which often indicated severe additional mental health issues, as does laxative abuse alone (Pryor et al. 1996). Others suggest that vomiting patterns are within a continuum of BN symptom severities with purging by vomiting associated with increased psychopathological disturbance (Newton et al. 1993, Gilbert 2005). Treatment effectiveness for BN is difficult to accurately determine, though cognitive behavioural therapy, according to Walsh et al. (1997), is ‘significantly more effective than supportive psychotherapy … in reducing the frequencies of binge eating and vomiting’ (p. 529). Agras et al. (2000), investigating a sample with BN, where 50% also experienced lifetime depression, also concluded cognitive behavioural therapy (CBT) to be five times more effective than psychotherapy in reducing vomiting. Though, importantly, after 1-year treatment, the outcomes for CBT and interpersonal psychotherapy are similar (Walsh et al. 1997). Fairburn et al. (1986) suggest the marked reduction in vomiting activity might result from education around body weight regulation, dieting and the adverse consequences of vomiting. Experience of depression and anxiety appear significant in the backgrounds of those with partial BN, with the use of alcohol and a chaotic family background prominent in those with full BN (Fairburn & Beglin 1990). The likely success of treatment depends on BN complexity, with associated substance misuse suggesting recovery likely to be prolonged (Wilson et al. 1999) and increased vomiting frequency greater than binge-eating in predicting poor outcome (Davis et al. 1992). There is also considerable evidence of increased vomiting activity when self-esteem is particularly low, depression is more pronounced and impulsivity is elevated (Keel et al. 2001, Watson et al. 2013). The role of impulsivity and its relationship to other elements, particularly low mood and poor self-concept is clearly complex, with Wu et al. (2013) arguing that the stopping component is impaired in BN. Impulsivity is characterized by ‘actions which are poorly conceived, prematurely expressed, unduly risky or inappropriate to the situation and that often result in undesirable consequences’ (Daruna & Barnes 1993, 23).