Post-Traumatic Stress Disorder (PTSD) and its Treatment

Authored by Henry Strick van Linschoten

Diagnosis of Post-Traumatic Stress Disorder (PTSD), DSM-IV and DSM-5 

Post-Traumatic Stress Disorder (PTSD) is the name for a combination of severely disabling symptoms that have been caused by trauma, which is defined in DSM-5 as exposure to actual or threatened death, serious injury or sexual violation. The exposure may involve directly experiencing the event; witnessing the event in person; learning about the event occurring to a close family member or close friend; or first-hand experience of extreme exposure (although not exposure through media or television coverage unless that exposure is work-related).

Diagnosis is generally based on the criteria set out in DSM-5 or ICD-10. The criteria in DSM-5 have slightly changed since DSM-IV-TR, in which they were grouped under three headings, (1) intrusion, (2) avoidance of trauma-related stimuli and numbing, and (3) increased arousal. DSM-5 has now expanded this to four headings (1) re-experiencing, (2) avoidance, (3) negative cognitions and mood, and (4) arousal.

In addition to the ‘flight’ reaction that was mainly emphasised in DSM-IV, the new DSM-5 brings out the ‘fight’ aspect of the traumatic response. DSM-5 also introduces some changes to the description of an event that qualifies as traumatic, including the addition of sexual assault and recurring exposure. Finally, PTSD has now been put into a newly created group of Trauma- and Stressor-Related Disorders, instead of being under the general heading of Anxiety Disorders.

PTSD can be formally diagnosed on the basis of interviews, either as part of the general Structured Clinical Interview for DSM-IV (First et al, 1997), or with the free-standing Clinician Administered PTSD scale (CAPS) (Blake et al, 1995). There are also self-report measures. All these methods will need to be updated in response to the DSM-5 changes.

Aetiology of Post-Traumatic Stress Disorder 

The simple view of aetiology is to see the original traumatic event or situation as the cause of the PTSD. However, people exposed to the same stressors have different reactions, and there are probably no events that leave 100% of exposed people with diagnosable PTSD. This has led clinical theoreticians to seek a more complete aetiological explanation. Despite the substantial amount of research expended on the question, there are only theories, and no complete answers as to why some people develop the symptoms of PTSD and others do not.

These theories can be divided between psychological and biological approaches, the latter being discussed in the paper on the neurobiology of PTSD. A complete theory would involve psychological as well as biological factors, including the relational and other developmental factors of the individual. A formulation distinguishing between the impact of the stressor and pre-existing vulnerability factors seems likely to give the fullest understanding.

Although there are several psychological theories about the cause of PTSD, none appears to be sufficient on its own, and none has a satisfactory evidence basis. The theories are:

  • Fear conditioning
  • Single or multiple meanings given to the event and its aftermath
  • Schema theories
  • Cognitive theories
  • Emotional processing theories
  • The special nature and characteristics of the traumatic memories
  • Symptom-maintaining factors

Summary descriptions of these models, with sources, can be found in Bisson (2009)Brewin & Holmes (2003)Cahill & Foa (2007)Taylor (2006), and Zoellner et al (2009).

It is not necessary for it to be known how an intervention works for that intervention to be effective. So trials of the effectiveness of particular treatments are a separate matter from assessments of the theories on which those treatments are based. However, given the importance generally accorded to psycho-education, the partial state of knowledge about the aetiology of PTSD is problematic.

Prevalence of Post-Traumatic Stress Disorder 

There is only limited evidence concerning the overall lifetime prevalence of PTSD in the general population, as most studies have focused on the development of PTSD in particular trauma categories (Kessler et al, 2009). The data available come from a limited number of studies in the USA and a few other developed countries.

One good-quality estimate showed that lifetime exposure to serious traumatic events as defined in DSM-IV-TR in the USA was 81% for men and 74% for women (Stein et al, 1997).

A number of distinctions between kinds of trauma are made:

  • single event compared with multiple event
  • interpersonal compared with impersonal
  • trauma experienced in childhood compared with trauma experienced later in life
  • types of trauma, e.g. differences between physical, sexual, and emotional child abuse
  • military or otherwise occupation-related trauma

Different types of trauma are associated with different rates of PTSD. In several studies rape was associated with the highest PTSD rates. Rates may vary from less than 10% to over 50%. There are no studies showing a particular type of trauma causing 100% of those exposed to develop PTSD.

Over a range of studies the incidence of PTSD comes out substantially higher for women than men. For example, in one of the few population-wide estimates, although old and based on the DSM-III-R definition, there was a lifetime prevalence for women of 10% compared with 5% for men. This was analysed as the result of women having a greater exposure to high-impact trauma, and women being more likely than men to develop PTSD when exposed to the same class of event (Kessler et al,1995). Also, according to the same source, the average risk of developing PTSD after trauma exposure is 20% for women and 8% for men (Kessler et al,1995).

There is currently a lack of good-quality studies about PTSD as a general phenomenon.

Treatment of Post-Traumatic Stress Disorder

The main conclusions from contemporary research evidence for the effectiveness of different types of psychotherapy for PTSD have been summarised in the paper ‘Controversies about PTSD’.

The two best-supported forms of psychotherapy for PTSD are Trauma-Focused CBT (TFCBT) and Eye Movement Desensitisation and Reprocessing (EMDR). The two elements they have in common are 1) revisiting the trauma in some form, and 2) cognitive processing. The exposure to trauma also arises in therapy with people suffering from Complex PTSD (C-PTSD), where it forms part of a larger and more complex therapy plan and environment. The empirical evidence for the success of interventions in (simple) PTSD is very strong. However, the strong evidence for the importance of re-visiting the trauma does not extend to a full understanding of how this works. For a summary of outstanding research issues see Moscovitch et al (2009).

As a general list of recommendations for working with PTSD, the International Society for Traumatic Stress Studies (ISTSS) guidelines are available in the final section of Foa et al (2009b) and online; different versions of the NICE Guidelines for PTSD (2006) are useful practical introductions.

Some good descriptions of different variants of TFCBT can be found here:

  • Andrews et al (2003). Follows general CBT principles, and includes a clinician guide and a patient treatment manual with useful suggestions for psycho-education.
  • Riggs et al (2006). Describes the process of prolonged exposure, compares a number of different exposure protocols, deals with a number of special considerations, and discusses the problems with dissemination of and training in prolonged exposure methods.
  • Foa et al (2009a). A therapist’s guide for a treatment protocol that is focused mainly on prolonged exposure as the way to emotional processing of the trauma. Practical and to the point, it is accompanied by a corresponding client workbook.
  • Taylor (2006). A careful and extensive description of a set of CBT methods, separating out emotional processing, cognitive interventions and exposure.

A description of EMDR can be found in Shapiro (2001) and (2002). There is extensive further literature about EMDR, although this does not replace actual practical training. EMDR is far more than just eye movements; it is based on a carefully developed protocol with strong cognitive-behavioural elements, including both exposure and cognitive processing. For training opportunities and further literature and resources, the EMDR websites ( are a good starting-point.

Based on the advice of practitioners, grounding techniques are an effective and much-used ingredient for working with trauma. Two examples can be found online on the website of the Canadian Centre for Addiction and Mental Health (CAMH Grounding, 2003) and in an excerpt from Najavits (2002). A wider repertoire of dealing with the physical and emotional in-session reactions to trauma work can be found in Rothschild (2000).


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Bisson, J.I. (2009). Psychological and social theories of post-traumatic stress disorder. Psychiatry. 8(8): 290-292.

Blake, D. D., Weathers, F. W., Nagy, L. M., Kaloupek, D. G., Gusman, F. D., Charney, D. S. & Keane, T. M. (1995). The development of a clinician-administered PTSD scale. Journal of Traumatic Stress 8(1): 75-90.

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Cahill, S.P. & Foa, E.B. (2007). Psychological Theories of PTSD. In M.J. Friedman, T.M. Keane & P.A. Resick (eds.). Handbook of PTSD: Science and Practice. New York: Guilford Press.

Centre for Addiction and Mental Health (CAMH) (2003). Grounding. Available at: 17 June 2013).

First, M.B., Spitzer, R.L., Gibbon, M. & Williams, J.B.W. (1997). User’s Guide for the Structured Clinical Interview for DSM-IV – Axis I Disorders. Clinician Version (SCID-CV). Washington, DC: American Psychiatric Press.

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Friedman, M.J., Keane, T.M. & Resick, P.A. (eds.) (2007). Handbook of PTSD: Science and Practice. New York: Guilford Press.

International Society for Traumatic Stress Studies (2009). ISTSS Treatment Guidelines for PTSD. Available at: (accessed 17 June 2013).

Kessler, R.C., Ruscio, A.M., Shear, K. & Wittchen, H. (2009). Epidemiology of Anxiety Disorders. In M.M. Antony & M.B. Stein (eds.). Oxford Handbook of Anxiety and Related Disorders. New York: Oxford University Press.

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