The Davidson Trauma Scale for Ptsd

Literature Review of the Construct

Post traumatic stress disorder received official recognition when it was first added to the Diagnostic and Statistical Manual of Mental Disorders in 1980(American Psychiatric Association1980).Posttraumatic stress disorder (PTSD) is characterized in the DSM by 17 symptoms (Davidson et al, 1997) , and is a pathological reaction to intense, overwhelming physical or psychological trauma. It is a disturbance in which identification, regulation and expression of affect are severely impaired (Davidson et al,1996). Considering the negative impact of PTSD on overall health and functioning and the availability of effective treatments there is a clear need for early identification of affiliated individuals (McDonald,Calhoun,2010). This growing focus on early identification has led to an increase of studies for measurements of PTSD(McDonald,Calhoun,2010). Examples of these clinician administered measurements include structured interviews of PTSD and Clinical Administered PTSD (CAPS) (Davidson et al, 1997).

The article by Blake et al(1995) discusses The Clinical Administered PTSD scale(CAPS). This scale is intended for use by clinicians and clinical researchers who have a working knowledge of PTSD. It assesses the 17 symptoms listed in the DSM-IV. It also includes five additional items involving the impact of symptoms on social and occupational functioning, improvement in PTSD symptoms since a previous CAPS assessment, and overall response validity and severity. The frequency and severity of each symptom is measured on a Likert scale and rated from 0 to 5 points. For each item, standard prompting and follow-up questions and behaviorally secured rating options are specified. First, questions are asked regarding current symptoms, then if criteria for PTSD is not met than the questions are repeated asking about the "worst ever" one month period after the trauma. Test-retest reliability, convergent validity, internal consistency and good sensitivity were all found in this scale. However, The Clinical Administered PTSD scale had many limitations. These limitations include; limits due to time (took forty five minutes to complete(Blake et al,1995)) and required the expertise of a qualified interviewer(Davidson et al, 1997). This test was relevant for combat veterans, however it may not work for other PTSD populations. By asking about current symptoms and then of a "worst ever" one month period after the event may overestimate PTSD symptomology(Blake et al,1997). Another type of PTSD measurements included self-ratings scales such as Impact of Event Scale.

An article by Horrowitz &Wilner(1979) will be examined to get a more in depth understanding of The Impact of Event Scale. This scale is used to assess current subjective distress for any life event. The items on this scale consist of twenty items that were taken from common statements used to describe episodes of distress. The twenty items on the scale were divided into two categories; nine describing intrusion and eleven describing avoidance. Due to the fact that the Impact of Event Scale was created before the DSM-III, it did not include hyper arousal symptoms(Davidson et al,1997). After many trial runs it was found that asking about the "past week" was most efficient for symptom recall. Although both frequency and severity of symptoms was asked of participants only the higher score was recorded. The specific life event and date of occurrence was recorded at the top of the page. This test was administered to 66 adults at the University of California who had pursued psychotherapy due to their reaction of a serious life event. Although The Impact of Event Scale demonstrated sensitivity, test-retest reliability and internal reliability there were many limitations of this scale. For example, hyper arousal symptoms were not included, and the findings with the 66 adults cannot necessarily be generalized to the others.

Additional measurements used for PTSD were Missississipi Scale, Penn Inventory and PTSD symptom scale. These scales(including The Impact of Event Scale) were limited due to reliability and validity as well as their lack of addressing the frequency and severity of symptoms(Davidson et al,1997). Therefore due to these limitations and the lack of a good measurement of PTSD the Davidson Trauma Scale(DTS) was developed.

Before examining the Davidson Trauma Scale it is important to note the possible issues that have faced and will face researchers when trying to measure Posttraumatic Stress Disorder. Most of these issues are present in diagnostic criteria. The first criterion for diagnosis of PTSD is a traumatic event that is outside the range of usual human experience and markedly distressing to almost everyone (Davidson,Foa,1991).This is important because if criterion is loose than the prevalence of PTSD will increase but if the scores are too restrictive diagnosis of PTSD will decrease (Davidson,Foa,1991). Therefore when developing a measurement for PTSD cut-off scores and criterion need to be taken into consideration as this could impact the diagnoses of PTSD. Another issue with the diagnostic criteria for PTSD is that it shares many of the same symptoms as panic disorder, phobic anxiety, generalized anxiety disorder(GAD), and obsessive-compulsive disorder (OCD) (Davidson,Foa,1991). Due to the fact that most psychiatric classification are still based on the first level: symptomatology(Davidson,Foa,1991), the awareness of convergent and discriminant validity is necessary. Also been found is the difference of criteria for diagnosis of PTSD in children, veterans and victims of natural disaster or crime(Davidson,Foa,1991). Therefore researchers should try to develop a measurement that is shown to be generalizable to these populations of individuals.

Overview of the Scale

The Davidson Trauma Scale was developed by J.R.T Davidson et al;(1997). This scale is self-rated and measures frequency and severity of each of the 17 DSM-IV symptoms as well as evaluates treatment of PTSD in individuals who have been exposed to a traumatic event or series of events. It can measure changes of symptoms over time, response prediction, and evaluation of differences between therapies (Davidson et al, 1997). This test was administered to 353 subjects; of these subjects 78 women were rape victims, 110 men were war veterans, and 53 were Hurricane Andrew victims. Different demographics were represented in the sample and included marital status, gender and race. By doing a literature review, the Davidson Trauma Scale was also found to be a useful in assessing Posttraumatic Stress Disorder symptoms in survivors of childhood sexual assault. Therefore this population can also be included in the intended use of this scale (Davidson,Zlotnick,Shea,Pearlstein(1996).It