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Posttraumatic Stress Disorder (PTSD)

General Information


  • trauma and stress-related disorder induced by exposure to ≥ 1 event that results in disturbances lasting ≥ 1 month1,2,3
  • disturbances include1,2,3,4
    • intrusive symptoms of mentally re-experiencing triggering event
    • avoidance of people, places, or things that are reminders of the traumatic event
    • negative changes in mood and cognition associated with the event
    • pervasive sense of imminent threat
    • persistence of hyperarousal or hypervigilance


  • acute PTSD lasts 1-2 months3
  • chronic PTSD lasts ≥ 3 months3
  • Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) specifiers include4
    • with dissociative symptoms - patient presents with symptoms meeting full criteria for PTSD, and experiences persistent or recurrent symptoms of either of the following
      • depersonalization - persistent or recurrent experiences of feeling detached from one's mental processes or body, such as feeling as if in a dream, or feeling sense of unreality of self or body
      • derealization - persistent or recurrent experiences of unreality of surroundings, such as the surrounding world feeling unreal, dreamlike, distant, or distorted
    • with delayed expression - patient symptom onset can be immediate, but full diagnostic criteria for PTSD not met until ≥ 6 months after triggering event


General references used

  1. Katzman MA, Bleau P, Blier P, et al; Canadian Anxiety Guidelines Initiative Group. Canadian clinical practice guidelines for the management of anxiety, posttraumatic stress and obsessive-compulsive disorders. BMC Psychiatry. 2014;14 Suppl 1:S1full-text
  2. Warner CH, Warner CM, Appenzeller GN, Hoge CW. Identifying and managing posttraumatic stress disorder. Am Fam Physician. 2013 Dec 15;88(12):827-34full-text, corrections can be found in Am Fam Physician 2015 Jul 1;92(1):10 and Am Fam Physician 2014 Mar 15;89(6):424
  3. Department of Veterans Affairs/Department of Defense (VA/DoD) guideline on management of posttraumatic stress disorder and acute stress disorder can be found at VA/DoD 2017 Jun
  4. Shalev A, Liberzon I, Marmar C. Post-Traumatic Stress Disorder. N Engl J Med. 2017 Jun 22;376(25):2459-2469, commentary can be found in N Engl J Med 2017 Nov 2;377(18):1796

Recommendation grading systems used

  • Canadian Anxiety Guidelines Initiative Group (CAGIG) grading system for recommendations
    • levels of evidence
      • Level 1 - meta-analysis or ≥ 2 randomized controlled trials (RCTs) including a placebo condition
      • Level 2 - ≥ 1 RCT with placebo or active comparison condition
      • Level 3 - uncontrolled trial with ≥ 10 subjects
      • Level 4 - expert opinion or anecdotal report
    • treatment recommendations
      • First-line - Level 1-2 evidence plus clinical support for safety and efficacy
      • Second-line - Level 3 evidence or higher plus clinical support for safety and efficacy
      • Third-line - Level 4 evidence or higher plus clinical support for safety and efficacy
      • Not recommended - Level 1-2 evidence for lack of efficacy
    • Reference - Canadian clinical practice guidelines for the management of anxiety, posttraumatic stress, and obsessive-compulsive disorders (25081580BMC Psychiatry 2014;14 Suppl 1:S1full-text)
  • Agency for Healthcare Research and Quality (AHRQ) grading system for recommendations
    • grades of recommendation
      • High - high confidence that evidence reflects true effect; confidence in estimate of effect very unlikely to change with further research
      • Moderate - moderate confidence that evidence reflects true effect; further research may change confidence in estimate of effect and estimate may change
      • Low - low confidence that evidence reflects true effect; further research likely to change confidence in estimate of effect and estimate likely to change
      • Insufficient - evidence unavailable or evidence does not allow estimation of effect
    • Reference - AHRQ Comparative Effectiveness Review 2013 Apr:109PDF (archived), summary can be found in 23683982Am J Prev Med 2013 Jun;44(6):635
  • United States Department of Veterans Affairs/Department of Defense (VA/DoD) uses Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system
    • Strong (For/Against) - work group highly confident desirable outcomes outweigh undesirable outcomes or vice versa
    • Weak (For/Against) - work group less confident of balance between desirable and undesirable outcomes
    • Reference - VA/DoD clinical practice guideline for management of posttraumatic stress disorder and acute stress disorder (VA/DoD 2017 Jun)

Synthesized Recommendation Grading System for DynaMed Content

  • The DynaMed Team systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based Methodology).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed content, we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE) to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed Team-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

  • DynaMed topics are created and maintained by the DynaMed Editorial Team and Process.
  • All editorial team members and reviewers have declared that they have no financial or other competing interests related to this topic, unless otherwise indicated.
  • DynaMed content includes Practice-Changing Updates, with support from our partners, McMaster University and F1000.

Special acknowledgements

  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T114915, Posttraumatic Stress Disorder (PTSD); [updated 2018 Nov 30, cited place cited date here]. Available from Registration and login required.

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EBSCO Information Services accepts no liability for advice or information given herein or errors/omissions in the text. It is merely intended as a general informational overview of the subject for the healthcare professional.


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