Post-Traumatic Stress Disorder (PTSD)
The DSM-IV definition for PTSD contains criteria for (a) the traumatic experience; (b) re-experiencing; (c) avoidance of associated stimuli and numbing; and (d) increased arousal. Duration of symptoms should be at least one month (e); and (f ) distress or impairment in functioning is required (APA, 1994). When PTSD was first defined in DSM-III (APA, 1980), the original stressor criterion characterised traumatic experiences as being outside the range of human experience. However, when the prevalence of such events was systematically examined, it became apparent that trauma is surprisingly commonplace. Several studies have investigated the overall prevalence of traumatic events in the general population, looking both at communitybased populations and populations of individuals at high risk of trauma or exposed to events such as natural disasters (Acierno et al., 1999). The nature of the trauma can be very diverse, such as childhood abuse, traffic accidents, fires, violent assault, robberies and floods or earthquakes.
Prevalence
Prevalence rates have increased from DSM-III to DSM-III-R and DSM-IV. Also, in some telephone interview surveys prevalence is much higher, and in studies among young persons where recall bias may be minimal. Kessler et al. (1995) reported on the National Comorbidity Survey of 5877 persons, aged 15 to 54 years. The estimated lifetime prevalence of PTSD was found to be 7.8%.
In routine clinical practice, PTSD is often underdiagnosed if the PTSD is not the presenting complaint but an additional diagnosis (Zimmerman and Mattia, 1999).
The same comment, however, can be made for other anxiety disorders, as social phobia (Kessler et al., 1999). Reasons for misdiagnosis of PTSD include a high rate of comorbidity, patient denial or minimisation, overly high diagnostic thresholds set by clinicians, or failure to take a trauma history (Davidson and Connor, 1999). In a cohort study of 185 persons involved in a traffic accident and a hotel fire, Maes et al. (1998) found after seven to nine months a prevalence of DSM-III-R PTSD of 23%.
Almost 50% of them had symptoms the first day, and about 70% developed PTSD symptoms during the first week after the event.
In one study, victims of substantiated child abuse and neglect were assessed and
compared with a group of matched non-abused and non-neglected children and followed into adulthood. Victims of child abuse (sexual and physical) and neglect were found to be at increased risk of developing PTSD. More than a third of the childhood victims of sexual abuse (37.5%), 32.7% of those physically abused, and 30.6% of victims of childhood neglect, met DSM-III-R criteria for lifetime PTSD.
Childhood victimisation, however, is not a suficient condition for developing PTSD, also family, individual, and lifestyle variables place individuals at risk and contributed to the symptoms of PTSD (Widom, 1999).
North et al. (1999) report on a follow-up on the terrorist Oklahoma City bombing in 1995 where a bomb blast killed 168 people. In their sample of 182 participating adults, 45% had a post-disaster psychiatric disorder and 34.3% had PTSD. The onset of PTSD was swift, with 76% reporting same-day onset. The relatively uncommon avoidance and numbing symptoms virtually dictated the diagnosis of PTSD (94% meeting avoidance and numbing criteria had full PTSD diagnosis) and were further associated with psychiatric comorbidity, functional impairment, and treatment received.
Intrusive re-experiencing and hyperarousal symptoms were nearly universal, but by themselves were generally unassociated with other psychopathology or impairment in functioning (North et al., 1999).
Demographics and Risk Factors
NCS data showed that prevalence was higher among women and the widowed, separated or divorced. The traumas most commonly associated with PTSD were combat exposure and witnessing violence among men and rape and sexual molestation among women. A variety of factors influence response to trauma and development of PTSD. They include characteristics of the stressor and exposure to it (e.g. repeated trauma increases the risk); individual factors such as gender (females are at higher risk), age and developmental level (the younger are at higher risk), and psychiatric history, family characteristics, and cultural factors (Pfefferbaum, 1997).
Natural Course
In the NCS survival analysis showed that more than one-third of people with an index episode of PTSD failed to recover even after many years (Kessler et al., 1995).
Among the subjects who had ever sought professional help (58% of affected respondents), the median time to remission was 36 months, among those who did not seek help the median time to remission was 64 months. A study of 61 Vietnam combat veterans with PTSD showed that onset of symptoms typically occurred at the time of exposure to combat trauma in Vietnam and increased rapidly during the first few years after the war. Symptoms plateaued within a few years after the war, following which the disorder became chronic and unremitting. Hyperarousal symptoms developed first, followed by avoidant symptoms, and finally by symptoms from the intrusive cluster. The onset of alcohol and substance abuse was associated with the onset of PTSD symptoms, and the increase in use paralleled the increase of symptoms (Bremner et al., 1996). Another recent study of Gulf War veterans showed that PTSD increases over time, two years after the war 8% of 2949 veterans had developed a PTSD, compared with 3% immediately following the war (Wolfe et al., 1999).
Comorbidity
Post-traumatic stress disorder in the NCS findings was strongly comorbid with other lifetime DSM-III-R disorders. A lifetime history of at least one disorder was present in 88.3% of men, and 79% of women with lifetime PTSD (Kessler et al., 1995).
Frequent comorbid diagnoses are: affective disorders (almost 50% of cases for major depression, 20% for dysthymia), other anxiety disorders (16% GAD, 9% panic disorder, 30% specific phobia, 28% social phobia, 19% agoraphobia, substance use disorders (52% alcohol and 34% drugs in men, 28% alcohol and 27% drugs in women) and conduct disorder (43% in men and 15% in women) (Kessler et al., 1995), and somatisation (McCauley et al., 1997).
