Eating disorders (EDs) and disordered eating have the highest mortality rate and treatment costs of all mental health conditions. EDs are characterised by persistently disrupted eating behaviours and often co-occur with poor self-image, anxiety, and depressive disorders. They are also associated with impaired physical health and psychological problems that contribute to diminished quality of life. Current estimates suggest that over 700,000 people in the UK are living with an eating disorder; however, this is largely considered to be an underestimate as many cases do not present to health services.
The DSM-5 (the standard classification of mental disorders used by mental health professionals in the US) currently recognises three primary EDs: anorexia nervosa (AN), bulimia nervosa (BN) and binge eating disorder (BED). The DSM-5 also recognises “other specified feeding or eating disorder” (OSFED), unspecified feeding or eating disorder (UFED), avoidant/restrictive food intake disorder (ARFID), pica, and rumination disorder (RD). EDs are considered to be among the most difficult psychiatric conditions to manage and treat with over 50% of ED patients reaching a severe and enduring stage of illness.
The mechanisms underlying ED symptomatology are complex and multifactorial and despite substantial research into ED aetiology and pathophysiology, few existing theoretical models have been translated into effective interventions. Despite high rates of relapse and treatment resistance among individuals with ED, there is a distinct lack of effective pharmacotherapies and alternative therapies for the treatment of these conditions. A recent review aimed to summarise the evidence base for pharmacotherapies and adjunctive and alternative therapies in the treatment of EDs and disordered eating.
Design and Methods of the Study
In 2021, the Australian government funded the InsideOut Institute for Eating Disorders (IOI) to develop the Australian Eating Disorders Research and Translation Strategy 2021-2031. The strategy was developed in partnership with state and national stakeholders including clinicians, service providers, researchers, and experts by lived experience (including consumers and families/carers) to provide a roadmap to establishing EDs as a national research priority. To inform the strategy, IOI commissioned Healthcare Management Advisors (HMA) to conduct a series of rapid reviews to broadly assess all available peer-reviewed literature on the six DSM-5 listed EDs.
The rapid review included eligible studies from three research databases (Science Direct, PubMed, and Ovid/Medline) that were published between 2009 and 2021. The focus of the review was to identify evidence relevant to developing optimal care pathways for individuals with EDs.
Results of the Study
The review outlined a distinct lack of research and evidence on pharmacotherapy, adjunctive, and alternative therapies for EDs. Evidence of efficacy of interventions was very limited with few relevant high quality clinical trials.
The most commonly prescribed medications for EDs are antidepressants and antipsychotics. However, the only pharmacotherapies with a solid evidence base and widespread regulatory approval are the selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine which has demonstrated efficacy in reducing binging/purging and preventing relapse in patients with BN, and the central nervous system stimulant lisdexamfetamine, which along with other ADHD medications (such as methylphenidate and dasotraline) was found to consistently reduce binge eating frequency in BED.
Despite many studies examining potential pharmacotherapies for AN, none demonstrated consistent efficacy, and none are recommended as a first-line treatment. One study included in the review evaluated dronabinol, a cannabinoid receptor agonist, against placebo in a trial of women with AN. This showed that women prescribed dronabinol were more likely to experience weight gain. There is also developing evidence for ghrelin analogues. Supportive evidence for SSRIs in AN is limited, yet clinicians continue to prescribe these medications against practice guidelines. However, evidence on emerging therapies, such as dronabinol and ghrelin analogues is very preliminary and there is a need for further studies to determine their efficacy on a population basis.
While the researchers acknowledge some limitations, largely owing to the rapid review’s broad-reaching and largely policy-driven intent, they note that the review was able to meet its objective to identify gaps in research that may warrant further investigation.
Despite the widespread use of medications, the findings of this rapid review highlight a lack of effective medications and adjunctive and alternative therapies in the treatment of EDs. As such it is important to improve research around promising therapeutics, as well as actively attempting to uncover novel treatments as well.