Complex PTSD (CPTSD) vs Borderline Personality Disorder (BPD): How to Tell the Difference

Written by Colter Bloxom, LPC

Colter is a licensed psychotherapist and the owner and Executive Director of Thrive Therapy. He specializes in the treatment of anxiety, OCD, identity issues, and more.

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Complex post-traumatic stress disorder (cPTSD) and borderline personality disorder (BPD) share some common symptoms, which is why they’re often confused, even by mental health professionals. Both conditions can come with intense emotions, interpersonal relationship struggles, and a history of trauma. 

But even though they overlap in some ways, it’s important to understand that research shows that CPTSD and BPD are distinct conditions. Not everyone with cPTSD has BPD symptoms, and vice versa. Understanding the similarities and differences between these two conditions is very nuanced, especially because BPD tends to come with such a high stigma. But they’re not the same thing, and understanding the difference can be an important step in getting the right kind of support.

Can complex PTSD be misdiagnosed as borderline personality disorder?

The short answer is that yes, cPTSD and BPD often are confused for each other and misdiagnosed.

One of the biggest reasons for this is that cPTSD isn’t officially recognized in the DSM-5, which is the manual therapists and psychiatrists use to diagnose mental health conditions. cPTSD is included in the International Classification of Diseases (ICD-11), which is used more often outside of the U.S. Because it’s not in the DSM, many clinicians in the U.S. default to diagnosing PTSD or BPD instead, even when cPTSD might be the more accurate fit.

This can create a lot of confusion, because cPTSD and BPD share a lot of overlapping symptoms. But it’s also important to remember that they’re not mutually exclusive. It’s entirely possible (and actually fairly common) for someone with BPD to also have cPTSD. 

Studies have found that nearly 80% of people with cPTSD could also meet the criteria for a BPD diagnosis. The reverse is also true — over 40% of people with BPD could also have cPTSD.

Similarities between BPD and cPTSD

Because both conditions often involve trauma, it makes sense that they have a lot of overlap in their symptoms. Here are some of the biggest similarities and the symptoms that can be present in both:

• Emotional dysregulation: Both BPD and cPTSD involve extreme emotional ups and downs. People with either condition may feel emotions more intensely than others, which makes it hard to stay calm or regulate feelings when they get overwhelming.
  
  
• Unstable relationships: Fear of abandonment and struggles with trust, and difficulty maintaining stable relationships are common in both conditions. This can lead to cycles of closeness and conflict in friendships and romantic relationships with others.
  
  
• Dissociation and identity struggles: Many people with cPTSD or BPD experience dissociation, which can feel like zoning out, feeling disconnected from reality, or even forgetting important events. Both can also involve an unstable sense of self (feeling unsure of who you really are or what you want in life)
  
  
• Self-harm and suicidal thoughts: Self-harm is more commonly associated with BPD, but people with cPTSD may also use self-injury as a way to cope. Both conditions can also come with suicidal thoughts, especially during times of extreme distress.
  
  
• History of trauma: Many people with BPD have experienced significant trauma, especially in early childhood. But not everyone with BPD has gone through traumatic experiences, which is one of the main things that differentiates it from cPTSD.

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How do I know if I have cPTSD or BPD? The key difference

Since cPTSD isn’t officially recognized in the DSM, many people who fit the criteria for it end up being diagnosed with PTSD or BPD instead. This can make it hard to know which diagnosis applies to you (or if both do). 

Again, it’s so important to remember that these conditions aren’t mutually exclusive. Many people with BPD also have cPTSD, and trauma is a common factor in both. The key difference is that cPTSD is defined by the presence of trauma-specific symptoms that BPD does not include.

If you have cPTSD, you’ll likely experience effects to your sense of self and relationships on top of more traditional PTSD symptoms.

• Hypervigilance: Feeling constantly on edge or easily startled, as if you’re always waiting for something bad to happen.
  
  
• Flashbacks and intrusive memories: Reliving past trauma through vivid memories, nightmares, or emotional flashbacks.
  
  
• Avoidance: Trying to avoid reminders of trauma, which can include people, places, or even certain emotions.
  
  
• Difficulty regulating emotions: You might feel like your emotions swing between extremes, or that you get overwhelmed more easily than other people.
  
  
• Negative self-perception: Experiencing intense shame or guilt, or feeling like you’re fundamentally broken or unlovable.

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On the other hand, the symptoms of BPD may look more like:

• Intense fear of abandonment: Going to great lengths (sometimes unconsciously) to prevent people from leaving, even when there’s no real threat of abandonment.
  
  
• Rapid mood swings: Shifting from feeling fine to feeling extreme anger, sadness, or emptiness within hours or even minutes.
  
  
• Impulsivity: Engaging in risky or impulsive behaviors, like reckless spending, unsafe sex, binge eating, or substance use.
  
  
• Extreme reactions in relationships: Splitting (seeing people as “all good” or “all bad”), intense arguments, or quickly idealizing and devaluing others.
  
  
• Chronic emptiness:  A persistent feeling of inner emptiness, like something important is missing or nothing really feels meaningful (even if you can’t put your finger on it)

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In addition, you must have experienced multiple and prolonged traumatic events — like being the victim of child abuse, being tortured, or experiencing prolonged intimate partner violence — for a diagnosis of cPTSD. You don’t need to have survived trauma to be diagnosed with BPD. 

If you relate to symptoms of both, that’s okay. A diagnosis is just something that helps guide treatment decisions. It doesn’t change what you’ve been through or what kind of support you need. What matters most is finding a treatment plan that actually helps.

Support for BPD and PTSD in Phoenix

Whether you relate more to CPTSD vs BPD (or both), you deserve treatment that actually addresses what you’re going through. Therapy can help with both conditions, but traditional once-a-week talk therapy isn’t always enough, especially if you’re dealing with more severe symptoms.

 At Thrive, we offer an intensive outpatient program (IOP) designed specifically for mental health — not just addiction treatment like many other programs. Our IOP meets three times a week (9 hours total) and provides structured support for people dealing with anxiety, PTSD, and personality disorders. We use evidence-based treatments, including dialectical behavior therapy (DBT), which has been shown to be highly effective for both BPD and complex trauma.

If you’re looking for more intensive support in Phoenix, reach out today for a free consultation and to learn more about the benefits of IOP for mental health. You don’t have to figure this out on your own.