Posttraumatic Stress Disorder (PTSD) is defined as a fear-based disorder with several features necessary for a formal diagnosis which include: avoidance behaviors, re-experiencing, increased arousal and negative affect and/or cognition.1 Avoidance behaviors may include avoiding people, places or situations that could be emotionally ‘triggering’ of a traumatic event. For example, some veterans may avoid amusement parks or festivities that have fireworks or excessive noise as it may cause flashbacks or anxiety.

Re-experiencing behaviors often include emotional flashbacks, intrusive thoughts or nightmares. Someone who has experienced an assault may have trouble sleeping or experience nightmares of their assailant long after a traumatic event. Negative affect or cognitions may additionally occur with PTSD which may include feeling detached, or blaming themselves for a traumatic event. Similarly, increased arousal is common with those experiencing symptoms of PTSD which may include aggression or self-sabotaging behavior. Self-medicating or self-defeating behavior is reported as a maladaptive coping strategy or a way to distract themselves from their emotional or psychological discomfort.

Whereas PTSD has the above features necessary for diagnosis, Complex Posttraumatic Stress Disorder (cPTSD) is often defined as a shame-based disorder, which includes the key features of PTSD plus three additional features, including emotional dysregulation, a negative self-image and interpersonal relationship issues.3 For example, those diagnosed with cPTSD may avoid relationships out of fear, have a negative self-concept, and display anger, sadness, emotional disconnection or dissociation.

Some core features of cPTSD have overlapping similarities with Borderline Personality Disorder (BPD), thus further blurring the distinctions among the three disorders. However, some key differences include a fear of abandonment that is specific to BPD and a more stable sense of self-identity seen in cPTSD that is not seen as consistently with BPD.

BPD is identified as a pervasive personality disorder often beginning in late adolescence or early adulthood and includes symptoms of recurrent suicidal behavior, identity disturbances, chronic feelings of emptiness, emotional dysregulation, and cycles of idealization and devaluation of others and self. Symptoms specific to BPD include frantic efforts to avoid perceived or actual abandonment, an unstable sense of self-identity, marked impulsivity, and unstable and intense interpersonal relationships.2

However, while there are similarities among the disorders, such as interpersonal relationship issues and emotional dysregulation, symptoms associated with BPD are often more chronic and less transient which may make BPD more challenging to treat.

Key Differences in Relationship Issues

All three conditions can struggle with healthy interpersonal relationships, however, there are some distinctions that separate the three disorders.

  • Those with PTSD, cPTSD and BPD often struggle with interpersonal relationships throughout the course of their diagnosis.
  • Those with cPTSD and BPD often report high incidences of childhood maltreatment which includes emotional, sexual, and physical abuse and neglect.
  • The highest reported durations, types, and incidences of ongoing child abuse are often reported by those diagnosed with cPTSD.4
  • Those diagnosed with cPTSD who have a history of childhood maltreatment and abuse are at an increased risk for being re-traumatized in adulthood, especially in intimate partner relationships.
  • Those with PTSD and cPTSD usually do not have a history of a fear of abandonment whereas those with BPD usually have a very deep fear of abandonment that often has caused significant impairment and instability within their interpersonal relationships.
  • Those with BPD are cyclic with idealization and devaluation within interpersonal relationships whereas this dynamic is not usually seen in those with PTSD or cPTSD.
  • Interpersonal relationship trust issues are common among all three disorders however trust issues seen in BPD often surround a fear of abandonment, which is not seen in PTSD or cPTSD.
  • Relationship issues are often external to those with PTSD or cPTSD, in which acts of violence, threats to their life, or situations out of their control may be a cause of their symptoms.
  • Relationship issues, especially relationship with self, are internal to those with BPD which affects their ability to have a stable self-identity or stable interpersonal relationships.
  • Those with PTSD may have interpersonal stressors, especially immediately following a traumatic event, however with proper intervention they may recover to baseline levels before trauma.
  • Those diagnosed with cPTSD may avoid relationships or “push away” social support as threatening or fear-inducing, which may be confused with a fear of abandonment seen in BPD.
  • What separates the behavior associated with relationship avoidance in cPTSD is the fear of relationships as threatening or dangerous rather than abandoning.
  • Those with BPD struggle with being alone; those with cPTSD or PTSD often choose to be alone or avoid relationships.
  • Those with cPTSD or PTSD may show improvement in interpersonal relationships with therapy and in learning adaptive coping strategies.

This is not an exhaustive list given the complexity and comorbidity among the disorders. If you or someone you know is struggling with symptoms relating to PTSD, cPTSD or BPD, speaking with a counselor who is trained in trauma and recovery may be helpful in building skills and assisting with coping strategies.


  1. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: Author.
  2. Cloitre, M., Garvert, D. W., Weiss, B., Carson, E. B., & Bryant, R. (2014). Distinguishing PTSD, complex PTSD, and borderline personality disorder: A latent class analysis. European Journal of Psychotraumatology, 5, 1–N.PAG.
  3. Frost, R., et al. (2020). Distinguishing complex PTSD from borderline personality disorder in individuals with a history of sexual trauma: A latent class analysis. European Journal of Trauma & Dissociation, 4, 1 – 8.
  4. Karatzia, T., et al. (2017). Evidence of distinct profiles of posttraumatic stress disorder and complex posttraumatic stress disorder based on the new ICD-11 trauma questionnaire. Journal of Affective Disorders, 207, 181 – 187.