The above studies indicate that the development and course of PTSD are variable. Some people may have no or few symptoms of PTSD initially but develop more symptoms over time and others may rapidly develop symptoms that meet the full diagnostic criteria for PTSD. Some recover or experience a reduction in symptoms, others suffer longstanding PTSD symptoms (Friedman et al. 1994; Kulka et al. 1990; Schnurr et al. 2003), and still others will follow an episodic course. Even those who appear to have recovered entirely from PTSD may experience a recurrence of symptoms years later, especially if exposed to additional trauma or other important life events, such as the death of a spouse (Friedman et al. 1994).
People with PTSD tend to report poor health and impaired function in many life activities. Several studies indicate that veterans with PTSD report more symptoms of adverse health and disability than do veterans without PTSD (see Chapter 6 for more information on symptom reporting). On examination, many people with PTSD are found to have other psychiatric disorders that increase the complexity of diagnosing PTSD. The presence of those additional psychiatric disorders may also play a role in the adverse health effects seen with PTSD.
In Chapter 6, studies are assessed for the strength of the association between deployment to a war zone and PTSD; those studies are found in the section on psychiatric disorders. The body of evidence that addresses specific health effects that may occur in veterans with PTSD is also reviewed in Chapter 6 for each relevant health effect. The psychosocial effects seen in veterans with PTSD, including effects on family and employment, are considered in Chapter 7.
In veteran and general population samples, PTSD frequently co-occurs with other psychiatric or substance-use disorders. In the NVVRS, male and female theater veterans with PTSD were 10-15 times more likely to have depression and dysthymia and 20 times more likely to have an anxiety disorder than their counterparts without PTSD (Kulka et al. 1990). Zatzick et al. (1997a) found that the risk of having PTSD was significantly greater in male NVVRS veterans with major depression (OR 17.6, 95% CI 6.5-47.4), alcohol abuse or dependence (OR 3.2, 95% CI 1.9-5.4), drug abuse or dependence (OR 7.4, 95% CI 2.2-24.5), or panic disorder (OR 22.6, 95% CI 3.1-163.5) that in those with the disorders. Among female veterans, PTSD was seen in 51% of those with major depression, 40.7% of those with alcohol abuse or dependence, and 70.1% of those with panic disorder (Zatzick et al. 1997b).
High rates of comorbidity are also seen in the general population. In the NCS, 88.3% of men and 79.0% of women with PTSD had a life history of mood, anxiety, or substance-use disorders (Kessler et al. 1995). The temporal relationship between PTSD and other psychiatric and substance-use disorders is complex. Psychiatric comorbidity increases the likelihood of PTSD, as found in the NCS. However, PTSD also increases the likelihood of developing the other disorders (Schnurr et al. 2000a, 2002; Shalev et al. 1998). Trauma can also lead to the simultaneous development of PTSD and other psychiatric disorders, such as major depression (Shalev et al. 1998). For example, in a study of 262 World War II and Korean War prisoners of war (Engdahl et al. 1998), half of whom developed war-related PTSD, 66% of those with PTSD but only 34% of those without PTSD had another anxiety, mood, or substance-use disorder. The