Eating Disorders and Co-occurring Complex PTSD: Research Gaps and Clinical Challenges

For individuals with eating disorders, the diagnosis is only part of the picture. 

Research shows that up to 50% of those diagnosed with eating disorders are admitted to higher levels of care also meet criteria for PTSD. Trauma co-occurs in millions of cases, yet it remains one of the most minimized factors in eating disorder treatment. With roughly 9% of Americans affected by eating disorders, the cost of overlooking that connection is profound, making recovery significantly harder to reach when left unaddressed.  

In practice, eating disorders rarely occur in isolation — trauma, depression, anxiety, and substance use disorders frequently accompany the picture, creating a clinical complexity that treatment must account for. For clinicians, understanding the connection between eating disorders and multi-morbidities is foundational to treatment.

In a continuing education event co-hosted by NEDA and The Dorm, Dr. Kimberly Dennis shared insights on the intersection of eating disorders, trauma, and co-occurring conditions. 

The event was held in recognition of National Eating Disorders Awareness Week, honoring NEDA’s theme of “Every BODY Belongs.” Below, we recap key insights from the conversation.

The Misunderstood Reality of Eating Disorders

Eating disorders are among the most misunderstood and underdiagnosed mental health conditions. When most people picture an eating disorder, they picture restriction or someone who is visibly underweight. However, this misunderstanding leaves out the vast majority of people actually living with one.

The DSM-5 identifies five main types of eating disorders, from most to least common:

• Other Specified Feeding and Eating Disorder (OSFED)
• Binge‑eating disorder
• Bulimia nervosa
• Anorexia nervosa
• Avoidant/Restrictive Food Intake Disorder (ARFID)

OSFED is the most frequently diagnosed, accounting for nearly 40% of all cases.

​​Eating disorders also affect people across every age, gender, body size, race, and background. LGBTQ individuals experience eating disorders at higher rates than their heterosexual and cisgender peers; BIPOC individuals are more likely to engage in disordered eating behaviors yet face significantly greater barriers to accessing care; and people with higher body weight have more than double the risk of disordered eating, while being about half as likely to receive a diagnosis or be connected to treatment.

Eating disorders rarely occur in isolation. 

The majority of those affected also live with a co-occurring mood or anxiety disorder, and approximately half have a co-occurring substance use disorder. Among individuals seeking higher levels of care, roughly half also present with a trauma-related disorder.

The Relationship Between Eating Disorders and Trauma

The research linking eating disorders and trauma is substantial. Trauma results from an event or series of events that felt physically or emotionally threatening and left a lasting impact on functioning. It typically predates the onset of an eating disorder, and the more adverse childhood experiences (ACEs) a person has, the greater their risk. 

Adolescents with four or more ACEs are nearly six times more likely to fall into the high eating disorder risk group, and among all forms of childhood maltreatment, sexual abuse carries the highest associated risk. Childhood trauma biologically rewires the brain, disrupting the prefrontal cortex’s ability to regulate hunger cues and eating decisions.

Childhood sexual abuse also rarely occurs in isolation. Those with that history are more likely to have experienced other forms of abuse as well, and more likely to have grown up in households affected by substance use, domestic violence, or an absent parent. They present with co-occurring conditions such as depression, anxiety, substance use disorders, and personality disorder, creating a level of complexity that standard treatment models are frequently not equipped to address.  

Why Trauma Often Goes Unaddressed in Treatment

Trauma frequently goes unrecognized by patients and clinicians alike. For patients, minimizing or denying traumatic experiences is common, particularly when that trauma was early and developmental. When someone grows up in an environment where neglect, abuse, or instability was the norm, it rarely registers as something worth reporting. When effects are delayed, the link between past events and current struggles can be nearly impossible to draw, and when dissociation or memory gaps are present, PTSD can go undetected entirely.

Traumatic experiences are also deeply layered with shame, confusion, and silence, all of which make them hard to surface in a clinical setting. Trauma shapes how people see themselves, and for someone with an eating disorder, those beliefs attach directly to food, body image, and daily functioning. Thought patterns like “it’s my fault,” “I can’t trust anyone,” or “nothing will ever change” erode trust in the therapeutic relationship and actively reinforce eating disorder behaviors — showing up as missed appointments, dropout from care, a high need for control, or behaviors that get labeled as attention-seeking or splitting.

Clinicians, in turn, can unconsciously follow the patient’s lead, focusing on whatever presenting issue feels most immediate and colluding with the avoidance without realizing it. In addition, patients with high trauma doses tend to have difficulty building trust in the therapeutic relationship and can have a hard time with secure attachment with a therapy team.

Understanding PTSD, C-PTSD, and D-PTSD

PTSD is significantly more common in people with eating disorders than in the general population. Research shows that people with co-occurring eating disorders and PTSD tend to have an earlier onset of illness, a more complex clinical course, higher rates of treatment dropout, and less favorable outcomes overall. 

Two subtypes are particularly relevant in eating disorder care: Dissociative Post Traumatic Stress Disorder (D-PTSD) and Complex Post Traumatic Stress Disorder (C-PTSD).

• D-PTSD involves depersonalization and derealization, a sense of floating outside oneself or feeling disconnected from reality.
• C-PTSD develops from prolonged or repeated trauma and includes not just core PTSD symptoms but also significant emotion dysregulation, a deeply negative self-concept, and difficulty in relationships. 

Early life stress can disrupt the brain’s reward pathway and the systems involved in habit formation, which helps explain why eating disorder behaviors can feel so compulsive and resistant to change. When either subtype co-occurs with an eating disorder, the clinical picture becomes more severe across every measure, including depression, anxiety, substance use, and quality of life.

This is why treating one condition without addressing the other consistently falls short. 

Trauma is often the thread connecting multiple diagnoses and symptoms, and waiting for eating disorder stabilization before approaching it is not an effective strategy. When both are treated together, outcomes significantly improve.

What Trauma-Informed Care Looks Like

Trauma-informed care starts with a fundamental shift in how clinicians show up and ask questions. Rather than asking “what’s wrong with you,” the question becomes “what happened to you?” The focus shifts to understanding how a symptom or behavior may have once been adaptive. Rather than prescribing treatment and expecting compliance, trauma-informed care is built on shared expertise, collaboration, and trust.

Developing trauma-informed treatment systems starts with three core commitments: 

• Recognizing how prevalent trauma is
• Understanding how it affects everyone involved in care including treatment providers
• Actively putting that knowledge into practice

As well as four pillars:

• Safety
• Structure
• Consistency
• Nurturance

Something as simple as showing up when you say you will, and doing so consistently, is one of the most trauma-informed things a clinician can do. Where traditional models prioritize symptom reduction, trauma-informed models prioritize understanding. Treatment is built on trust rather than coercion, and on mutuality rather than control.

Don’t Wait to Treat the Trauma

One of the most important things clinicians can do for patients with co-occurring eating disorders and trauma is treat both conditions at the same time. Waiting until the eating disorder is under control, or until a patient is weight restored, is not an effective approach. For many people, getting there requires trauma treatment from the start. 

The only circumstances that warrant delaying trauma treatment are active safety concerns, suicidal ideation with plan and intent, or eating disorder symptoms that are compromising medical stability.

Integrated treatment means the same team, in the same setting, addressing all conditions together. When care is cohesive and providers are aligned around the whole person, outcomes are meaningfully better.

Conclusion

What this collaborative event ultimately demonstrates is that it is very common for trauma‑related disorders to go missed, minimized or undiagnosed in clinical settings. For many patients, unaddressed trauma is the underlying factor driving eating disorder symptoms, treatment dropout, and repeated setbacks in care. Recovery is possible, but it requires an integrated treatment philosophy rooted in relationship, trust, and willingness to treat the whole person rather than presenting symptoms alone.