A clinical approach to the assessment and management of co-morbid eating disorders and substance use disorders

Introduction: Research has shown that eating disorder (ED) patients who abuse substances demonstrate worse ED symptomatology and poorer outcomes than those with EDs alone, including increased general medical complications and psychopathology, longer recovery times, poorer functional outcomes and higher relapse rates. This article provides a broad overview of the prevalence, aetiology, assessment and management of co-morbid EDs and substance use disorders (SUDs). Review: The co-occurrence of EDs and SUDs is high. The functional relationship between EDs and SUDs vary within and across ED subtypes, depends on the class of substance, and needs to be carefully assessed for each patient. Substances such as caffeine, tobacco, insulin, thyroid medications, stimulants or over the counter medications (laxatives, diuretics) may be used to aid weight loss and/or provide energy, and alcohol or psychoactive substances could be used for emotional regulation or as part of a pattern of impulsive behaviour. A key message conveyed in the current literature is the importance of screening and assessment for co-morbid SUDs and EDs in patients presenting with either disorder. There is a paucity of treatment studies on the management of co-occurring EDs and SUDs. Overall, the literature indicates that the ED and SUD should be addressed simultaneously using a multi-disciplinary approach. The need for medical stabilization, hospitalization or inpatient treatment needs to be assessed based on general medical and psychiatric considerations. Common features across therapeutic interventions include psycho-education about the aetiological commonalities, risks and sequelae of concurrent ED behaviours and substance abuse, dietary education and planning, cognitive challenging of eating disordered attitudes and beliefs, building of skills and coping mechanisms, addressing obstacles to improvement and the prevention of relapse. Emphasis should be placed on building a collaborative therapeutic relationship and avoiding power struggles. Cognitive behavioural therapy has been frequently used in the treatment of co-morbid EDs and SUDs, however there are no randomized controlled trials. More recently evidence has been found for the efficacy of dialectical behavioural therapy in reducing both ED and substance use behaviours. Conclusion: Future research would benefit from a meta-analysis of the current research in order to better understand the relationships between these two commonly co-occurring disorders.