In a previous post, I looked at the varieties of traumatic experiences and their risk of inducing PTSD in men and women. Another aspect of the epidemiology of PTSD is a more basic look at the overall prevalence of exposure to individual traumatic experiences.
There has been significant discussion and research to define the trauma severity required to increase risk of a PTSD response. Early studies tended to have a lower threshold for severity. They included not only a personal experience of trauma but also learning that a friend or family member had experienced trauma. More recent research has required a more direct personal experience for the traumatic experience.
Using an earlier, less restrictive definition, up to ninety percent of survey population reported at least one trauma significant enough for PTSD. The most prevalent traumatic experiences (1996 Detroit area survey)1. Sudden unexpecte death of a close friend or relative (60%)2. Learned close friend/relative was seriously injured in a motor vehicle crash (39%)3. Learned that a close friend/relative was raped or sexually assaulted (33%)4. Witnessed someone being killed or seriously injured (29%)5. Personal serious car or motor vehicle crash (28%)
The WHO international study of trauma used a more restrictive list of serious traumatic events and found the prevalence rates for lifetime trauma ranged between 2 and 31%. The most common traumas reported among those with a traumatic experience were:1. Death of a loved one (31%)2. Witness to violence (22%)3. Interpersonal violence (19%)4. Accidents (18%)5. Exposure to war (16%)6. Trauma to a loved one (13%)
Look forward to additional description of the WHO survey of prevalence and patterns of trauma exposure throughout the world.
Photo of Kenyan Zebra Courtesy of Sarah Yates
Breslau, N. (1998). Trauma and Posttraumatic Stress Disorder in the Community: The 1996 Detroit Area Survey of Trauma Archives of General Psychiatry, 55 (7), 626-632 DOI: 10.1001/archpsyc.55.7.626
Stein DJ, Chiu WT, Hwang I, Kessler RC, Sampson N, Alonso J, Borges G, Bromet E, Bruffaerts R, de Girolamo G, Florescu S, Gureje O, He Y, Kovess-Masfety V, Levinson D, Matschinger H, Mneimneh Z, Nakamura Y, Ormel J, Posada-Villa J, Sagar R, Scott KM, Tomov T, Viana MC, Williams DR, & Nock MK (2010). Cross-national analysis of the associations between traumatic events and suicidal behavior: findings from the WHO World Mental Health Surveys. PloS one, 5 (5) PMID: 20485530
PTSD represents a pathological response to a serious trauma. The evolution of the diagnostic criteria for PTSD has included a broadening of the types of trauma exposures felt sufficient to trigger PTSD. The original criteria included combat, concentration camp confinement, natural disaster, rape or physical assault. The current DSM-IV criteria for trauma require that "the person experienced, witnessed or was confronted with an event(s) that involved actual or threatened death or serious injury or a threat to the physical integrity of self or others"
Naomi Breslau from the Michigan State summarized the current state of knowledge regarding the epidemiology of trauma and PTSD--much of which she has been a key research leader. With the expanded trauma trigger definition, it is estimated approximately 40 to 80% of the U.S. population have experienced one of these traumas. General population surveys of PTSD complement our knowledge of PTSD outside military personnel.
Only a minority of trauma exposures appear to result in PTSD. Women appear more vulnerable to a PTSD response than men. Here is the estimated highest risk traumas for women (% of individuals experiencing the trauma who develop PTSD):
Women- Held captured/tortured (78%)
- Severe physical assault with injury (56%)
- Rape (49%)
- Lesser assault (36%)
- Serious accident (28%)
- Sexual assault other than rape (24%)
Men- Shot or stabbed (18%)
- Child life threatening illness (18%)
- Sexual assault (16%)
- Sudden, unexpected death of relative or friend (13%)
- Witnessing a killing/serious injury (9%)
In addition to female gender, presence of a prior childhood anxiety disorder appears to increase risk. Higher IQ (>115) appears to provide some protective effect.
Prevention of PTSD starts with public health efforts to reduce violent crime and the frequency of severe trauma exposure in the population. Military service related trauma is also a key area for prevention and early intervention. Secondary prevention efforts include identifying those exposed to serious trauma, assessing for high risk for PTSD following this trauma and early therapy or pharmacologic intervention.
Photo of male lion in Kenya courtesy of Sarah Yates
Breslau N (2009). The epidemiology of trauma, PTSD, and other posttrauma disorders. Trauma, violence & abuse, 10 (3), 198-210 PMID: 19406860
