Many learning theorists speculate that the major symptoms of PTSD are caused by a classical conditioning to fear (Fairbank and Brown, 1987; Keane, Zimering, & Caddell, 1985).  In this model, a patient with PTSD may experience increased anxiety or fear when traveling in a car (CS), after having been involved in a traumatic car accident (UCS).  Avoidance of motor vehicles only serves to negatively reinforce the fear of cars--when the car is not present, neither is the anxiety.  This is a good example of the two-factor theory of avoidance developed by Mowrer (1947)

From a biological viewpoint, lasting changes in brain chemistry are often evident in the patient diagnosed with PTSD (Kosten, Mason, Giller, Ostroff, & Harkness, 1987).  People with PTSD have heightened physiological responses (startle reflex, etc.) to any physical stress--not just traumatic reminders  (Krystal, Kosten, Southwick, et al., 1989; Van der Kolk, Greenberg, Boyd, & Krystal, 1985).

When the sympathetic nervous system is activated to prepare for an emergency, the region of the brain known as the "locus coeruleus" releases the catecholamine neurotransmitters norepinepherine and epinepherine (nonadrenaline and adrenaline)  (Charney, Ariel, Deutch, & Krystal, 1993).  Many studies, including that of Henry, Haviland, Cummings, et al., (1992)  show that patients with PTSD may have characteristic catecholamine abnormalities.  They have found that a high norepinephrine/cortisol ratio is a useful indicator of PTSD.

Given exposure to a traumatic event, predictors of PTSD are being female, early seperation from parents, family history of a disorder, preexisting disorder (i.e., panic disorder, OCD, depression), parental poverty, child abuse,  and seperation or divorce of parents prior to the age of 10 (Davidson, Hughes, Blazer, & George, 1991; Davison & Neale, 1998).

à Link to "Symptoms" for more information.

Questions?  E-mail the author: Gregory Bayse 

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