Most PTSD sufferers have heightened physiological arousal in response to sounds, images, and thoughts related to specific traumatic incidents, while others have decreased arousal. Initial research on acute trauma victims found that people with PTSD, but not controls, respond to reminders with significant increases in heart rate, skin conductance, and blood pressure (Pitman et al., 1987). The elevated sympathetic responses to reminders of traumatic experiences that happened years, and sometimes decades, ago illustrate the intensity and timelessness with which these trauma imprints continue to affect current experience (Pitman et al., 1987). Post and his colleagues (1992) have shown that life events play a critical role in the first episodes of major affective disorders but become less pertinent in precipitating subsequent occurrences. This capacity of triggers with diminishing strength to produce the same response over time is called kindling. About one third of chronically traumatized people respond to reminders of their past with decreased arousal: They appear to respond primarily with a parasympathetic reaction. This population has received little scientific scrutiny.
Medications that decrease autonomic arousal, such a ¡3-adrenergic blockers, cloni-dine and benzodiazepines, tend to decrease traumatic intrusions, while drugs that stimulate autonomic arousal may precipitate visual images and affect states associated with prior traumatic experiences in people with PTSD, but not in controls. For example, in patients with PTSD the injection of drugs such as lactate (Rainey et al., 1987) and yohimbine (Southwick et al., 1993) tend to precipitate panic attacks, flashbacks (exact reliving experiences) of earlier trauma, or both. In our own laboratory, approximately 20 percent of PTSD subjects responded with a flashback of a traumatic experience when they were presented with acoustic startle stimuli.
Was this article helpful?