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eating-disorders.jpgComorbid eating disorders and PTSD: The public health burden
The overlap between eating disorders and posttraumatic stress disorder (PTSD) is well documented. Systematic reviews and meta analyses suggest that anywhere from 18% to 25% of individuals with eating disorders (EDs) also experience PTSD, and 12% of people with PTSD endorse eating disorder symptoms (Ferrell et al., 2022). EDs are associated with one of the highest morbidity and mortality rates of any psychiatric disorder (van Hoeken & Hoek, 2020). Because of this medical risk, clinicians often describe feeling unsure of how best to manage ED behaviours in the context of trauma-focused treatments. Often, they report a fear that engaging in trauma-focused therapy will exacerbate ED behaviours, particularly when clients describe trauma-related memories as triggers for engaging in these behaviours. As a result, clients may be denied, or at least delayed, in receiving trauma-focused treatment until their ED behaviours are managed. However, if the ED behaviours are used to cope with trauma-related thoughts and emotions, delaying trauma-focused treatment may only serve to maintain these behaviours as a maladaptive coping strategy for untreated trauma symptoms, and unnecessarily prolong clients’ suffering.
The functional model of ED and PTSD
Researchers have pointed to a reinforcing functional relationship in which EDs serve to avoid trauma-related thoughts and memories (e.g., Trottier, 2016; Mitchell et al., 2021). From this perspective, individuals may use maladaptive strategies like food restriction, bingeing, or purging as an attempt to manage trauma-related hyperarousal and avoid trauma-related thoughts, emotions, and memories. This avoidance prevents the trauma from being examined and accepted, which further perpetuates trauma-related symptoms, and ED behaviours to cope with them. Several cross sectional and longitudinal studies have provided support for a functional relationship between EDs and PTSD. Network analysis studies have identified illness pathways between PTSD intrusive and hyperarousal symptoms with ED behaviours (e.g., binge eating, body dissatisfaction; e.g., Liebman et al., 2020). At least one study using ecological momentary assessment showed that individuals with PTSD have greater daily levels of negative affect, more frequent purging behaviours, and faster acceleration in positive affect after purging than those without PTSD (Karr et al., 2013). En masse, these studies suggest that ED behaviours may be a particularly potent short-term emotion regulation strategy for individuals with PTSD, and underscore ED behaviours as a particularly reinforcing method of managing the distress associated with PTSD.
Treatment outcomes of EDs and PTSD
Several studies have examined the impact of comorbid ED-PTSD on treatment outcomes with the understanding that the added clinical complexity may negatively impact treatment outcomes of both disorders. Interestingly, two recent systematic reviews found that individuals with ED and either trauma or PTSD show equivalent improvement in their ED symptoms to their peers with EDs and no trauma or PTSD. However, they are more likely to drop out or relapse in their ED after treatment is over (Convertino, 2023; Day, 2023). From a functional perspective, PTSD symptoms may increase when clients interrupt their ED behaviours because they no longer have these behaviours to cope with their trauma-related symptoms. As a result, clients may drop out because they experience these increases in PTSD symptoms as intolerable. Clients who do complete treatment may struggle to maintain symptom improvement when faced with trauma reminders and other untreated PTSD symptoms after treatment is over.
Importantly, few studies have examined the impact of ED symptoms on PTSD outcomes. However, a functional perspective would imply that unmanaged ED symptoms would impede improvement in PTSD symptoms. The few studies that have examined the impact of ED symptoms on PTSD treatment outcomes indicate that ED symptoms may interfere with PTSD recovery and, further, that ED symptoms do not improve as a result of trauma-focused treatments (e.g., Mitchell et al., 2012). Thus, it appears that without direct behavioural intervention to interrupt ED behaviours, along with trauma-focused work to address unresolved thoughts and feelings about the trauma, recovery from both ED and PTSD remains incomplete. Addressing the ED-PTSD symptom constellation holistically through a functional lens may be necessary to achieve full and lasting recovery.
Integrated treatments for comorbid EDs and PTSD
Integrated treatments may offer an efficient strategy to address comorbid PTSD and EDs. Based on the premise that EDs serve an avoidant function for trauma-related thoughts and memories, effective treatment requires teaching clients to tolerate and process trauma-related reminders without using ED behaviours as an avoidance strategy. In contrast to sequential or staged treatments, which treat the ED and PTSD separately, and usually prioritize remission in ED behaviours before initiating trauma focused treatment, integrated treatments conceptualize the ED behaviour as functionally related to the PTSD symptoms and aim to treat them holistically.
To date, few integrated treatments have been developed or tested for comorbid ED-PTSD, even though numerous ED-PTSD researchers have advocated that integrated treatments are the optimal treatment approach (Mitchell et al., 2021; Trottier et al., 2016). One integrated, partially sequential treatment, a combination of Cognitive Processing Therapy and Cognitive Behavioral Therapy – Enhanced, has been tested and found to be effective in achieving both ED and PTSD symptom remission that is sustained at 6-month follow up (Trottier et al., 2022). The treatment includes ED relapse prevention including maintaining a regular pattern of eating, interrupting ED behaviours, challenging food rules, and body image work, followed by adapted CPT that integrates a discussion of ED behaviours as a form of avoidance from trauma-related thoughts and feelings. The CPT sessions prioritize beliefs or “stuck points” about the eating disorder in relation to the trauma, (e.g., “The rape happened because of the shape of my body,” “I can’t tolerate thinking about my trauma without binging”). Whenever possible, clinicians emphasize the relationship between the trauma and eating disorder, for example, by targeting food rules that are related to the trauma (e.g., avoiding foods that are trauma reminders) or body avoidance behaviours aimed at preventing revictimization (e.g., wearing baggy clothes to protect oneself from being assaulted again). 
Clinical considerations for treating comorbid EDs and PTSD
Clinicians often fear exacerbating ED behaviours further when clients describe trauma-related memories as triggers for these ED behaviours. As a result, they may delay or discourage trauma-focused treatment out of concern that the client is not ready or is too unstable to proceed. In some cases, trauma-focused treatment may need to be delayed or discontinued in favor of medical stabilization, weight restoration, or potentially a full course of ED treatment, particularly where patients are so low weight that they may not be cognitively capable of engaging in trauma processing. Excessive bingeing and purging also poses medical risks that may require medical stabilization prior to engaging in trauma focused work. However, guidance on these considerations is lacking, and at least one recent study has tested a concurrent trauma-focused treatment using Imaginal Rescripting in low-weight patients receiving ED treatment in an inpatient setting who ranged in body mass index (BMI) of 14.6 to 18.4 (mean BMI = 16.7; ten-Napel Shutz et al., 2022). Other examples of successfully delivered trauma-focused treatments have been documented for patients with BMIs as low as 15 (Trottier & Monson., 2021). More research is needed to understand the minimum nutritional and medical stabilization necessary for patients to benefit from trauma-focused treatment. However, if supported by further research, these findings suggest that with proper medical support and ongoing ED care, patients may be able to tolerate and benefit from trauma-focused treatment at greater levels of ED severity than previously thought.
Clinicians often describe feeling unsure of how best to manage ED behaviours in the context of trauma-focused treatments. By helping clients tolerate and process trauma-related reminders without using destructive behaviours as an avoidance strategy, clinicians will treat both conditions more effectively. Clinical formulations that incorporate a functional relationship between PTSD and ED symptoms may provide an important first step, and integrated treatments may be a promising approach to finding lasting recovery.
Key Words: Eating disorders, PTSD, integrated treatments, bingeing, purging, comorbidity
About the author
Dr. Rachel Liebman is a registered clinical psychologist in private practice and Assistant Professor at the University of Toronto. Dr. Liebman has over 15 years of experience treating disorders of emotion dysregulation in individuals, couples, and families. She specializes in the treatment of co-occurring trauma-related disorders and high-risk problem behaviours such as eating disorders, self-harm, and suicide, and she provides trainings and consultation to clinicians on the assessment and treatment of these conditions using integrated evidence-based approaches internationally. She is a board member of the International Society for Traumatic Stress Studies and served on the Task Force for the Ontario Structured Psychotherapy Program for Gender Based Violence. She conducts research on development and adaptation of treatments for high-risk populations and has published widely on these topics.
Convertino, A. D., & Mendoza, R. R. (2023). Posttraumatic stress disorder, traumatic events, and longitudinal eating disorder treatment outcomes: A systematic review. International Journal of Eating Disorders, 56(6), 1055-1074.
Day, S., Hay, P., Tannous, W. K., Fatt, S. J., & Mitchison, D. (2023). A systematic review of the effect of PTSD and trauma on treatment outcomes for eating disorders. Trauma, Violence, & Abuse, 15248380231167399.
Ferrell, E. L., Russin, S. E., & Flint, D. D. (2022). Prevalence estimates of comorbid eating disorders and posttraumatic stress disorder: A quantitative synthesis. Journal of Aggression, Maltreatment & Trauma, 31(2), 264-282.
Liebman, R. E., Becker, K. R., Smith, K. E., Cao, L., Keshishian, A. C., Crosby, R. D., ... & Thomas, J. J. (2021). Network analysis of posttraumatic stress and eating disorder symptoms in a community sample of adults exposed to childhood abuse. Journal of Traumatic Stress, 34(3), 665-674.
Karr, T. M., Crosby, R. D., Cao, L., Engel, S. G., Mitchell, J. E., Simonich, H., & Wonderlich, S. A. (2013). Posttraumatic stress disorder as a moderator of the association between negative affect and bulimic symptoms: An ecological momentary assessment study. Comprehensive Psychiatry, 54(1), 61-69.
Mitchell, K. S., Scioli, E. R., Galovski, T., Belfer, P. L., & Cooper, Z. (2021). Posttraumatic stress disorder and eating disorders: maintaining mechanisms and treatment targets. Eating Disorders, 29(3), 292-306.
Mitchell, K. S., Wells, S. Y., Mendes, A., & Resick, P. A. (2012). Treatment improves symptoms shared by PTSD and disordered eating. Journal of Traumatic Stress, 25(5), 535-542.
Ten Napel-Schutz, M.C., Vroling, M., Mares, S.H.W. et al. (2022). Treating PTSD with Imagery Rescripting in underweight eating disorder patients: A multiple baseline case series study. Journal of Eating Disorders, 10, 35
Trottier, K., & Monson, C. M. (2021). Integrating cognitive processing therapy for posttraumatic stress disorder with cognitive behavioral therapy for eating disorders in PROJECT RECOVER. Eating Disorders, 29(3), 307-325.
Trottier, K., Monson, C. M., Wonderlich, S. A., & Crosby, R. D. (2022). Results of the first randomized controlled trial of integrated cognitive-behavioral therapy for eating disorders and posttraumatic stress disorder. Psychological Medicine, 52(3), 587-596.
Trottier, K., Wonderlich, S. A., Monson, C. M., Crosby, R. D., & Olmsted, M. P. (2016). Investigating posttraumatic stress disorder as a psychological maintaining factor of eating disorders. International Journal of Eating Disorders. 49(5), 455–457.
Van Hoeken, D., & Hoek, H. W. (2020). Review of the burden of eating disorders: Mortality, disability, costs, quality of life, and family burden. Current Opinion in Psychiatry, 33(6), 521-527.