PTSD vs Complex PTSD: Differences, Symptoms and Treatment for Veterans

PTSD and complex PTSD (CPTSD) are two separate diagnoses in the WHO's ICD-11. Both share three core symptoms: re-experiencing the trauma, avoidance of reminders and a persistent sense of current threat. CPTSD adds three long-lasting difficulties with emotions, self-image and relationships. The American DSM-5 has no separate CPTSD diagnosis. Among UK Armed Forces personnel surveyed in 2022 to 2023, most people who met criteria for probable PTSD also met the extra criteria for CPTSD.

This article gives general information from official guidance and published studies. Only a qualified clinician can assess an individual and recommend treatment.

PTSD and CPTSD side by side

The ICD-11 definition describes symptoms only. It does not require a particular type of trauma. The VA Center for PTSD makes the same point and notes that earlier proposals linked CPTSD to prolonged early trauma. The NHS describes CPTSD as having largely the same symptoms as PTSD, linked to prolonged or repeated trauma such as childhood abuse or ongoing domestic abuse.

What the diagnostic manuals say

ICD-11, the WHO classification, gave CPTSD its own code (6B41) alongside PTSD (6B40). A 2017 review of the evidence by Brewin and colleagues found broad support for separating the two. It described CPTSD as a distinct group with more frequent multiple or prolonged trauma and greater functional impairment. You can browse the codes in the WHO ICD-11 browser.

The American Psychiatric Association's DSM-5-TR lists PTSD with four symptom groups: intrusion, avoidance, negative changes in thinking and mood, and changes in arousal and reactivity. The APA states that symptoms must last for more than a month and cause significant distress or impairment. The VA Center for PTSD adds that DSM-5 expanded its PTSD criteria to cover symptoms such as persistent negative mood and created a dissociative subtype.

How common are they in veterans

Figures differ by country, era, sample and questionnaire, so compare them with care.

The UK figures come from the King's College London Centre for Military Health Research (KCMHR) Phase 4 report, published in 2024, and a 2026 paper in Occupational and Environmental Medicine. In the UK cohort, 191 of the 275 people with ICD-11 probable PTSD met criteria for CPTSD. The Danish figures come from people already seeking treatment, so they run higher than a general veteran survey. The authors of that Journal of Psychiatric Research study found people with CPTSD were more likely to report depression, anxiety, stress, psychotropic medication use and suicide attempts than people with PTSD alone.

The Danish study identified combat exposure, a longer time since the trauma and being single as risk factors for CPTSD. Our article on combat exposure and the shape of trauma covers those findings in detail.

Treatment guidance in the UK and the US

Neither the NICE guideline nor the VA/DoD guideline sets a different treatment pathway for CPTSD. Both recommend trauma-focused psychological therapy as the first choice.

A 2025 review of reviews in the British Medical Bulletin by Billings and Nicholls found continued support for trauma-focused therapy, including with people who have CPTSD. Phase-based approaches that begin with stabilisation also showed benefit, though the authors conclude that more research is needed on adapting treatment for CPTSD. Dropout from therapy remains high across studies.

The full texts are on the NICE website and the VA/DoD provider summary. A clinician can explain how they apply to a particular person.

Getting assessed

The VA Center for PTSD states that only a mental health provider can diagnose PTSD. Screening questionnaires such as the 20-item PCL-5 help clinicians track symptoms and identify probable PTSD, and a structured clinical interview remains the standard for diagnosis. The International Trauma Questionnaire is the self-report tool built around the ICD-11 criteria, and the Danish study used it.

In England, veterans can contact Op COURAGE directly, through a family member or friend, or via a GP or charity. You need to be resident in England, have served at least one full day in the UK Armed Forces and be registered with, or eligible to register with, a GP. NHS talking therapies also accept self-referral from age 18 in most areas. In the US, contact your local VA facility or Vet Center . Our guide to Op COURAGE explains the UK service in more detail.