Skip to content

PTSD — Diagnosis and classification

TL;DR — PTSD diagnosis depends on both exposure and symptom/impairment rules; screening scores alone are not diagnoses. CAPS-5 is the best-established DSM-5 structured interview and PCL-5 is a self-report severity/screening measure (Weathers 2018, PMID 28493729) (Blevins 2015, PMID 26606250) (Bovin 2016, PMID 26653052). ICD-11 intentionally narrows the syndrome and separates complex PTSD, producing non-interchangeable populations (Brewin 2017, PMID 29029837) (Cloitre 2018, PMID 30178492). Criterion-A boundaries and index-trauma selection remain consequential sources of prevalence and trial-eligibility variation.

Case definition

DSM-5’s broader symptom architecture improves descriptive coverage but allows more heterogeneous combinations; ICD-11 prioritises clinical utility and parsimony (Brewin 2017, PMID 29029837). A prevalence or treatment estimate must identify which system and version was used.

Exposure gate

Criterion A is not a severity scale. Direct experience, witnessing, learning of violent/accidental trauma to a close other, and repeated occupational exposure are bounded routes; ordinary stressors are not automatically qualifying. Studies using symptom screens without a verified qualifying event estimate probable PTSD symptoms, not diagnostic PTSD (Weathers 2018, PMID 28493729) (Blevins 2015, PMID 26606250).

Instrument roles

CAPS-5 provides interviewer-rated diagnosis/severity; PCL-5 supports screening and repeated measurement. In the veteran validation sample, PCL-5 scores of 31 to 33 were optimally efficient for diagnosing PTSD against a CAPS-5 reference standard in a 140-participant subsample, with κ(.5)=.58 — a moderate, not decisive, level of agreement (Bovin 2016, PMID 26653052). Cut points depend on setting and base rate and should be locally validated rather than transported (Weathers 2018, PMID 28493729). The ITQ targets ICD-11 PTSD/CPTSD and should not be substituted for DSM-5 measures (Cloitre 2018, PMID 30178492).

Differential diagnosis and pooling

Symptoms overlap with depression, panic, GAD, sleep disorders, substance effects, TBI and grief. A pooled anxiety-disorder validation does not establish PTSD accuracy. Depression is handled in the separate depression condition and GAD in the neighbouring GAD condition; PTSD pages retain only PTSD strata (Carpenter 2018, PMID 29451967).

Measurement consequences

Changing the case definition changes prevalence, severity distribution and apparent response. Crosswalks cannot assume equal thresholds. Trials should report item-level or harmonisable data so DSM- and ICD-defined strata can be reconstructed (Brewin 2017, PMID 29029837) (Karatzias 2017, PMID 27723542).

Quantitative anchors

Measure Estimate Population/method Source
DSM-5 structure 20 symptoms in four clusters Broader symptom set than ICD-11 (Weathers 2018, PMID 28493729)
ICD-11 PTSD six core symptoms in three clusters Requires impairment (Brewin 2017, PMID 29029837)
CAPS-5 reliability inter-rater κ=.78–1.00 Two veteran samples, n=165 and 207 (Weathers 2018, PMID 28493729)
PCL-5 initial α=.94; test–retest r=.82 Trauma-exposed students, n=278 (Blevins 2015, PMID 26606250)
PCL-5 veteran α=.96; test–retest r=.84 VA samples, n=468 (Bovin 2016, PMID 26653052)
ITQ development 12 items Community n=1,051; clinical n=247 (Cloitre 2018, PMID 30178492)
PCL-5 diagnostic cut point 31–33; κ(.5)=.58 vs CAPS-5 Veteran subsample, n=140 (Bovin 2016, PMID 26653052)
CAPS-5 test–retest κ=.83; total-severity ICC=.78 Same veteran samples (Weathers 2018, PMID 28493729)
CAPS-5 vs CAPS-IV agreement κ=.84 when optimally calibrated Same veteran samples (Weathers 2018, PMID 28493729)

Evidence ledger

The ledger lists the live-retrieved records used to bound this page. Inclusion does not make every record equally probative; design, population and comparator remain decisive.

PMID Year Evidence contribution Scope caution
28493729 2018 The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5): Development and initial psychometric evaluation in military veterans. PTSD-specific record; inspect design and population
26606250 2015 The Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5): Development and Initial Psychometric Evaluation. PTSD-specific record; inspect design and population
26653052 2016 Psychometric properties of the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (PCL-5) in veterans. PTSD-specific record; inspect design and population
30178492 2018 The International Trauma Questionnaire: development of a self-report measure of ICD-11 PTSD and complex PTSD. PTSD-specific record; inspect design and population
29029837 2017 A review of current evidence regarding the ICD-11 proposals for diagnosing PTSD and complex PTSD. Synthesis: preserve included-population and certainty limits
27723542 2017 Evidence of distinct profiles of Posttraumatic Stress Disorder (PTSD) and Complex Posttraumatic Stress Disorder (CPTSD) based on the new ICD-11 Trauma Questionnaire (ICD-TQ). PTSD-specific record; inspect design and population
35780794 2022 Complex post-traumatic stress disorder. PTSD-specific record; inspect design and population
32345416 2020 ICD-11 complex post-traumatic stress disorder: simplifying diagnosis in trauma populations. PTSD-specific record; inspect design and population
34249244 2021 PTSD and complex PTSD in treatment-seeking Danish soldiers: a replication of Folke et al. (2019) using the International Trauma Questionnaire. PTSD-specific record; inspect design and population
31984942 2019 Testing the validity of ICD-11 PTSD and CPTSD among refugees in treatment using latent class analysis. PTSD-specific record; inspect design and population
33680347 2018 The structure of ICD-11 PTSD and complex PTSD in Lithuanian mental health services. PTSD-specific record; inspect design and population
29868234 2018 Are posttraumatic stress disorder (PTSD) and complex-PTSD distinguishable within a treatment-seeking sample of Syrian refugees living in Lebanon? PTSD-specific record; inspect design and population
24785767 2014 Rates of post-traumatic stress disorder in trauma-exposed children and adolescents: meta-analysis. Synthesis: preserve included-population and certainty limits
30261912 2018 Posttraumatic stress disorder: from diagnosis to prevention. PTSD-specific record; inspect design and population
37355148 2023 Equine-Assisted Therapy in Post-Traumatic-Stress Disorder: A Systematic Review and Meta-Analysis. Synthesis: preserve included-population and certainty limits
38032650 2024 Asynchronous assessment with the PCL-5: Practice considerations and recommendations. PTSD-specific record; inspect design and population
30779926 2019 Resting respiratory sinus arrhythmia and posttraumatic stress disorder: A meta-analysis. Synthesis: preserve included-population and certainty limits
29451967 2018 Cognitive behavioral therapy for anxiety and related disorders: A meta-analysis of randomized placebo-controlled trials. Synthesis: preserve included-population and certainty limits
32063234 2020 Psychological treatments for post-traumatic stress disorder in adults: a network meta-analysis. Synthesis: preserve included-population and certainty limits
32284821 2020 Psychological therapies for post-traumatic stress disorder in adults: systematic review and meta-analysis. Synthesis: preserve included-population and certainty limits
32813696 2020 Psychological and pharmacological interventions for posttraumatic stress disorder and comorbid mental health problems following complex traumatic events: Systematic review and component network meta-analysis. Synthesis: preserve included-population and certainty limits
26574151 2016 Psychological treatments for adults with posttraumatic stress disorder: A systematic review and meta-analysis. Synthesis: preserve included-population and certainty limits
17084063 2007 Pseudo-PTSD. PTSD-specific record; inspect design and population
17728312 2007 Post-traumatic stress disorder. PTSD-specific record; inspect design and population
26877093 2018 25 years of Eye Movement Desensitization and Reprocessing (EMDR): The EMDR therapy protocol, hypotheses of its mechanism of action and a systematic review of its efficacy in the treatment of post-traumatic stress disorder. Synthesis: preserve included-population and certainty limits

Interpretation guardrails

  • Trauma exposure, post-traumatic symptoms, acute stress disorder, DSM-5 PTSD, ICD-11 PTSD and ICD-11 complex PTSD are not interchangeable populations.
  • A mixed-anxiety or transdiagnostic estimate is labelled as such; only a source’s PTSD stratum can be treated as a PTSD effect.
  • Comorbid depression is measured separately and cross-linked to the depression condition; it is not absorbed into PTSD.
  • Waitlist, treatment-as-usual, attention control and active treatment answer different causal questions.
  • Registration, statistical significance and diagnostic loss do not respectively prove completion, clinical importance or functional recovery.
  • This page synthesizes research and does not provide individual medical advice.

Minimum extraction frame for studies on this topic

Field What must be retained Why it changes interpretation
Diagnostic system DSM version, ICD version, full/subthreshold Case mix is not interchangeable
Diagnostic method Structured interview, clinician judgment, self-report cutoff Screening is not diagnosis
Index trauma Type, timing, repetition, direct/indirect/occupational Conditional risk and phenotype differ
Population Civilian, veteran, refugee, child/adolescent, mixed Transportability is empirical
Baseline severity Mean, SD, range and exclusion threshold Ceiling and floor effects alter change
CPTSD status ITQ/ICD-11 definition and DSO score Complexity cannot be inferred from trauma count
Comorbidity Depression, GAD, SUD, pain, TBI measured separately Shared symptoms can distort effects
Comparator Waitlist, usual care, attention, active treatment The estimand changes with comparator
Treatment dose Sessions offered/attended, duration, homework Assignment is not exposure
Outcome Symptoms, diagnosis, response, function, sleep Outcomes are not interchangeable
Time point End point and prespecified follow-up windows Acute benefit may not persist
Missing data Denominator, reasons, imputation and estimand Attrition can bias rank and magnitude
Adverse events Definitions, ascertainment and arm-level counts Absence of reporting is not absence of harm
Therapist/context Training, fidelity, allegiance, setting Delivery is part of the intervention
Funding/conflicts Sponsor role and analytic independence Especially material for proprietary packages

Claims this page does not make

  • It does not infer PTSD from trauma exposure alone.
  • It does not treat a self-report cutoff as equivalent to a structured diagnosis.
  • It does not convert a pooled anxiety-disorder effect into a PTSD effect.
  • It does not convert a depression outcome in a comorbid sample into a PTSD outcome.
  • It does not infer superiority from a statistically significant within-group change.
  • It does not infer equivalence from a non-significant between-group test.
  • It does not infer effectiveness from trial registration or mechanistic plausibility.
  • It does not assume military, civilian, refugee and pediatric estimates transport unchanged.
  • It does not average conflicting estimates that use different definitions.
  • It does not treat lack of adverse-event reporting as evidence of safety.

Evidence-updating triggers

Trigger Required response
New diagnostic revision Recalculate which populations prior estimates represent
New head-to-head RCT Compare against active treatment, not only waitlist
New individual-participant synthesis Revisit effect modifiers and transportability
Registry status change Verify results and linked publication before changing conclusions
Guideline update Separate evidence review from panel recommendation
Regulatory decision Record decision date and source; do not infer from efficacy papers
Safety signal Re-extract denominator, ascertainment and exposure time by arm
Contradictory replication Display estimates side by side; do not average definitions

Evidence updates should preserve the prior estimate and explain why the new study changes—or does not change—the inference.

Open questions

  • Can one calibration study estimate transportable CAPS-5, PCL-5 and ITQ thresholds across civilian, veteran, refugee and adolescent settings? (Weathers 2018, PMID 28493729) (Cloitre 2018, PMID 30178492)
  • Which Criterion-A boundary decisions cause the largest change in case counts and prognosis? (Brewin 2017, PMID 29029837)
  • Do DSM-5-only trials contain enough item-level data to reconstruct ICD-11 PTSD/CPTSD treatment effects? (Cloitre 2018, PMID 30178492)

References

  1. Weathers FW, et al. The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5): Development and initial psychometric evaluation in military veterans. Psychol Assess. 2018;30(3):383-395. PMID 28493729
  2. Blevins CA, et al. The Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5): Development and Initial Psychometric Evaluation. J Trauma Stress. 2015;28(6):489-98. PMID 26606250
  3. Bovin MJ, et al. Psychometric properties of the PTSD Checklist for Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition (PCL-5) in veterans. Psychol Assess. 2016;28(11):1379-1391. PMID 26653052
  4. Cloitre M, et al. The International Trauma Questionnaire: development of a self-report measure of ICD-11 PTSD and complex PTSD. Acta Psychiatr Scand. 2018;138(6):536-546. PMID 30178492
  5. Brewin CR, et al. A review of current evidence regarding the ICD-11 proposals for diagnosing PTSD and complex PTSD. Clin Psychol Rev. 2017;58:1-15. PMID 29029837
  6. Karatzias T, et al. Evidence of distinct profiles of Posttraumatic Stress Disorder (PTSD) and Complex Posttraumatic Stress Disorder (CPTSD) based on the new ICD-11 Trauma Questionnaire (ICD-TQ). J Affect Disord. 2017;207:181-187. PMID 27723542
  7. Maercker A, et al. Complex post-traumatic stress disorder. Lancet. 2022;400(10345):60-72. PMID 35780794
  8. Cloitre M ICD-11 complex post-traumatic stress disorder: simplifying diagnosis in trauma populations. Br J Psychiatry. 2020;216(3):129-131. PMID 32345416
  9. Folke S, et al. PTSD and complex PTSD in treatment-seeking Danish soldiers: a replication of Folke et al. (2019) using the International Trauma Questionnaire. Eur J Psychotraumatol. 2021;12(1):1930703. PMID 34249244
  10. Vang ML, et al. Testing the validity of ICD-11 PTSD and CPTSD among refugees in treatment using latent class analysis. Torture. 2019;29(3):27-45. PMID 31984942
  11. Kazlauskas E, et al. The structure of ICD-11 PTSD and complex PTSD in Lithuanian mental health services. Eur J Psychotraumatol. 2018;9(1):1414559. PMID 33680347
  12. Hyland P, et al. Are posttraumatic stress disorder (PTSD) and complex-PTSD distinguishable within a treatment-seeking sample of Syrian refugees living in Lebanon? Glob Ment Health (Camb). 2018;5:e14. PMID 29868234
  13. Alisic E, et al. Rates of post-traumatic stress disorder in trauma-exposed children and adolescents: meta-analysis. Br J Psychiatry. 2014;204:335-40. PMID 24785767
  14. Miao XR, et al. Posttraumatic stress disorder: from diagnosis to prevention. Mil Med Res. 2018;5(1):32. PMID 30261912
  15. Palomar-Ciria N, et al. Equine-Assisted Therapy in Post-Traumatic-Stress Disorder: A Systematic Review and Meta-Analysis. J Equine Vet Sci. 2023;128:104871. PMID 37355148
  16. Taylor LS, et al. Asynchronous assessment with the PCL-5: Practice considerations and recommendations. Psychol Serv. 2024;21(3):552-559. PMID 38032650
  17. Campbell AA, et al. Resting respiratory sinus arrhythmia and posttraumatic stress disorder: A meta-analysis. Biol Psychol. 2019;144:125-135. PMID 30779926
  18. Carpenter JK, et al. Cognitive behavioral therapy for anxiety and related disorders: A meta-analysis of randomized placebo-controlled trials. Depress Anxiety. 2018;35(6):502-514. PMID 29451967
  19. Mavranezouli I, et al. Psychological treatments for post-traumatic stress disorder in adults: a network meta-analysis. Psychol Med. 2020;50(4):542-555. PMID 32063234
  20. Lewis C, et al. Psychological therapies for post-traumatic stress disorder in adults: systematic review and meta-analysis. Eur J Psychotraumatol. 2020;11(1):1729633. PMID 32284821
  21. Coventry PA, et al. Psychological and pharmacological interventions for posttraumatic stress disorder and comorbid mental health problems following complex traumatic events: Systematic review and component network meta-analysis. PLoS Med. 2020;17(8):e1003262. PMID 32813696
  22. Cusack K, et al. Psychological treatments for adults with posttraumatic stress disorder: A systematic review and meta-analysis. Clin Psychol Rev. 2016;43:128-41. PMID 26574151
  23. Rosen GM, et al. Pseudo-PTSD. J Anxiety Disord. 2007;21(2):201-10. PMID 17084063
  24. Bisson JI Post-traumatic stress disorder. Occup Med (Lond). 2007;57(6):399-403. PMID 17728312
  25. Novo Navarro P, et al. 25 years of Eye Movement Desensitization and Reprocessing (EMDR): The EMDR therapy protocol, hypotheses of its mechanism of action and a systematic review of its efficacy in the treatment of post-traumatic stress disorder. Rev Psiquiatr Salud Ment (Engl Ed). 2018;11(2):101-114. PMID 26877093