Posttraumatic Stress Disorder (PTSD)

Posttraumatic Stress Disorder (PTSD) is a mental disorder diagnosed after an exposure to trauma, including actual or threatened death, serious injury, or sexual violation. It is characterized by intrusive and distressing memories or dreams, dissociative reactions, and substantial psychological or physiological distress related to the event. A diagnosis of PTSD requires evidence of exposure to trauma, and is characterized by intrusive and dissociative symptoms.


The lifetime prevalence of PTSD is around 6-9%, and up to 30% in US Vietnam War veterans.[1] It is more frequent in women than in men, with an onset generally in the mid to late 20s. PTSD is associated with high rates of functional impairment, somatic complaints, suicide risk, and comorbid psychiatric disorders.


PTSD symptoms can be chronic, lasting years to decades after the initial trauma.[2][3] However, individuals generally have substantially improved occupational functioning at work, relationships, and social interactions.[4] Long-term employment disability related to PTSD is also rare. In general, clinicians and patients should expect that functioning will improve significantly over the long term, even if posttraumatic stress symptoms remain.


PTSD presents with comorbid psychiatric disorders, especially depressive disorders, anxiety disorders, and/or substance use disorders. Close to half of individuals seeking substance use disorder treatment also meet criteria for current PTSD, and individuals with co-occurring disorders tend to have poorer treatment outcomes compared with those without such comorbidity. Epidemiological research on PTSD has shown consistently that pre-existing psychopathology is a strong predictor of PTSD following a trauma exposure. These comorbid conditions should also be treated concurrently with PTSD.

Risk Factors
Criterion A (Exposure)

Exposure to actual or threatened death, serious injury, or sexual violence in at least 1 of the following ways:

  1. Directly experiencing the traumatic event(s).
  2. Witnessing, in person, the event(s) as it occurred to others.
  3. Learning that the traumatic event(s) occurred to a close family member or close friend. In cases of actual or threatened death of a family member or friend, the event(s) must have been violent or accidental.
  4. Experiencing repeated or extreme exposure to aversive details of the traumatic event(s) (e.g. - first responders collecting human remains or police officers repeatedly exposed to details of child abuse).
Note: Criterion A4 does not apply to exposure through electronic media, television, movies, or pictures, unless this exposure is work related.
Criterion B (Intrusion Symptoms)

Presence of at least 1 of the following intrusion symptoms associated with the traumatic event(s), beginning after the traumatic event(s) occurred:

  1. Recurrent, involuntary, and intrusive distressing memories of the traumatic event(s). In children older than 6 years, repetitive play may occur in which themes or aspects of the traumatic event(s) are expressed.
  2. Recurrent distressing dreams in which the content and/or affect of the dream are related to the traumatic event(s). In children, there may be frightening dreams without recognizable content.
  3. Dissociative reactions (flashbacks) in which the individual feels or acts as if the traumatic event(s) were recurring. (Such reactions may occur on a continuum, with the most extreme expression being a complete loss of awareness of present surroundings.) In children, trauma-specific reenactment may occur in play.
  4. Intense or prolonged psychological distress at exposure to internal or external cues that symbolize or resemble an aspect of the traumatic event(s).
  5. Marked physiological reactions to internal or external cues that symbolize or resemble an aspect of the traumatic event(s).
Criterion C (Avoidance)

Persistent avoidance of stimuli associated with the traumatic event(s), beginning after the traumatic event(s) occurred, as evidenced by 1 or all of the following:

  1. Avoidance of or efforts to avoid distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s).
  2. Avoidance of or efforts to avoid external reminders (people, places, conversations, activities, objects, situations) that arouse distressing memories, thoughts, or feelings about or closely associated with the traumatic event(s).
Criterion D (Negative Cognition and Mood)

Negative alterations in cognitions and mood associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred, as evidenced by at least 2 of the following:

  1. Inability to remember an important aspect of the traumatic event(s) (typically due to dissociative amnesia and not to other factors such as head injury, alcohol, or drugs).
  2. Persistent and exaggerated negative beliefs/expectations about oneself, others, or the world (e.g., “I am bad,” “No one can be trusted,” ‘The world is completely dangerous,” “My whole nervous system is permanently ruined”).
  3. Persistent, distorted cognitions about the cause or consequences of the traumatic event(s) that lead the individual to blame himself/herself or others.
  4. Persistent negative emotional state (e.g., fear, horror, anger, guilt, or shame).
  5. Markedly diminished interest or participation in significant activities.
  6. Feelings of detachment or estrangement from others.
  7. Persistent inability to experience positive emotions (e.g., inability to experience happiness, satisfaction, or loving feelings).
Criterion E (Changes in Arousal)

Marked alterations in arousal and reactivity associated with the traumatic event(s), beginning or worsening after the traumatic event(s) occurred, as evidenced by at least 2 of the following:

  1. Irritable behavior and angry outbursts (with little or no provocation) typically expressed as verbal or physical aggression toward people or objects.
  2. Reckless or self-destructive behavior
  3. Hypervigilance
  4. Exaggerated startle response
  5. Problems with concentration
  6. Sleep disturbance (e.g., difficulty falling or staying asleep or restless sleep).
Criterion F

Duration (Criteria B, C, D, and E) is more than 1 month.

Criterion G

The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.

Criterion H

The disturbance is not attributable to the physiological effects of a substance (e.g., medication, alcohol) or another medical condition.



Specify if: Specify whether:

  • With dissociative symptoms: The individual’s symptoms meet the criteria for post traumatic stress disorder, and the individual experiences persistent or recurrent symp toms of either of the following:
  • 1. Depersonalization: Persistent or recurrent experiences of feeling detached from, and as if one were an outside observer of, one’s mental processes or body (e.g., feeling as though one were in a dream; feeling a sense of unreality of self or body or of time moving slowly).
  • 2. Derealization: Persistent or recurrent experiences of unreality of surroundings (e.g., the world around the individual is experienced as unreal, dreamlike, distant, or distorted). Note: To use this subtype, the dissociative symptoms must not be attributable to the physiological effects of a substance (e.g., blackouts) or another medical condition (e.g., complex partial seizures).
  • With delayed expression: If the full diagnostic criteria are not met until at least 6 months after the event (although the onset and expression of some symptoms may be immediate).


The clinical presentation of PTSD can be remembered by the mnemonic TRAUMA[5]

  • T - Traumatic event (experienced, witnessed, or was confronted, and the person experienced intense helplessness, fear, and horror)
  • R - Re-experiencing (intrusive thoughts, nightmares, flashbacks, or traumatic memories/images)
  • A - Avoidance (emotional numbing, detachment from others, flattening of affect, loss of interest, lack of motivation, and persistent avoidance of things associated with the traumatic experience)
  • U - Unable to function (symptoms cause negative mood, distress, or cause significant impairment in social, occupational, and interpersonal life)
  • M - 1 month of symptoms (at least)
  • A - Arousal increased (insomnia, poor concentration, irritable, angry, startle reflex, hypervigilance)

PTSD is unique among the psychiatric diagnoses in that it requires a specific external event as part of the diagnostic criteria. Incorrect application of the trauma exposure criterion (Criterion A) by clinicians and researchers has led to misdiagnosis and erroneously high prevalence rates of PTSD.[6] It is important to recognize that most trauma exposures does not result in PTSD. The symptoms from PTSD must be linked temporally and conceptually to the traumatic exposure to qualify as PTSD symptom.

PTSD Diagnosis Algorithm (Adapted from: Downs, D. L. (2018). PTSD: A systematic approach to diagnosis and treatment. Current Psychiatry, 17(4), 35. Fig. 1

The amygdala, hippocampus, and prefrontal cortex are all involved in the stress response. Traumatic stress can be associated with lasting changes in these brain areas. Individuals with PTSD have smaller hippocampal and anterior cingulate volumes, increased amygdala function, and decreased medial prefrontal/anterior cingulate function. Patients with PTSD also show increased cortisol and norepinephrine responses to stress.[7]

Brain imaging studies have shown alterations in a circuit including medial prefrontal cortex (including anterior cingulate), hippocampus, and amygdala in PTSD.

Both pharmacotherapy and psychotherapy are beneficial for treatment of PTSD. Research has not conclusively shown either treatment modality to be superior than the other. The following treatment recommendations are based on the 2014 Canadian Clinical Practice Guidelines for anxiety, posttraumatic stress and obsessive-compulsive disorders:[8]

Treatment should start with one of the first-line options, either an SSRI or an SNRI. If there is poor response or tolerability, the patient should be switched to another first- or second-line agent. Alternatively, a second-line agent can be added (patients with PTSD may make few gains during treatment, and it is important to preserve even small gains). Augmentation with second- or third-line agents can be important early in treatment. Patients who do not respond to multiple courses of therapy are considered to have treatment-refractory illness. In such patients it is important to reassess the diagnosis and consider comorbid medical and psychiatric conditions that may be affecting response to therapy.

Pharmacotherapy for Posttraumatic Stress Disorder

1st line Fluoxetine, paroxetine, sertraline, venlafaxine XR
2nd line Fluvoxamine, mirtazapine, phenelzine
3rd line Amitriptyline, aripiprazole, bupropion SR, buspirone, carbamazepine, desipramine, duloxetine, escitalopram, imipramine,
lamotrigine, memantine, moclobemide, quetiapine, reboxetine, risperidone, tianeptine, topiramate, trazodone
Adjunctive therapy* Second-line: eszopiclone, olanzapine, risperidone
Third-line: aripiprazole, clonidine, gabapentin, levetiracetam, pregabalin, quetiapine, reboxetine, tiagabine
Not recommended: bupropion SR, guanfacine, topiramate, zolpidem
Not recommended Alprazolam, citalopram, clonazepam, desipramine, divalproex, olanzapine, tiagabine

If there is a co-morbid substance use disorder, sertraline is recommended as the medication of choice.

Pharmacotherapy for PTSD-associated nightmares

1st line Prazosin
2nd line Naltrexone, fluphenazine

Trauma-Focused CBT (TF-CBT), Prolonged Exposure (PE) therapy, and Cognitive Processing Therapy (CPT) has significant efficacy. Eye movement desensitization and reprocessing therapy (EMDR) has also emerged as a trauma-focused therapy with effectiveness.