Psychology and cognitive processing in post-traumatic disorders

The term PTSD was introduced into the American Psychiatric Association’s Diagnostic and Statistical Manual in 1980 and the definition has since been refined into the current DSM-IV1 (and DSM-IV (TR)) definitions and those in the equivalent ICD-9 and ICD-10 of the World Health Organization.2 Current diagnostic criteria as set out in DSM-IV require a person to have been exposed to one or more traumatic events where they felt that their life or someone else’s was under threat, or that they or others were going to be injured and where, at some stage, they felt helpless or terrified. It is the phenomenon of suddenly realizing that one is going to die or become seriously injured, accompanied by strong feelings of terror and/or helplessness, which produces the features of PTSD. These symptoms may appear soon after the event or at some time later (see Table 1). Diagnostic criteria as set out in DSM-IV require symptoms to be present for 4 weeks or more before a diagnosis can be made, with problems emerging before this time being described either as ‘acute stress disorder’ or what are termed ‘adjustment reactions or disorders’. Not all people suffering from acute stress disorder, which requires a certain degree of post-traumatic dissociation to be present, go on to develop PTSD, and many later go on to develop PTSD without prior acute post-traumatic dissociation. If symptoms do not materialize before 6 months then a ‘delayed onset’ is said to have occurred (and these forms of PTSD are usually the more difficult ones to treat psychologically) and if the symptoms last for more than just 1 month, then the disorder is said to be ‘chronic’.