lence) than earlier, less sensitive estimates (Kessler, 2000; Kessler et al., 1995). Using time series analysis, Kessler (2000) found that current PTSD significantly predicts subsequent first onset of all other anxiety disorders, substance use disorders, major depression, and dysthymia for males and females. Furthermore, PTSD predicts the onset of mania in males, with an odds ratio of 15.5. Given the overwhelming presence of co-occurring mental disorders in those with PTSD (Chu, 1999), Kessler (2000) made another significant discovery in demonstrating that only those with active PTSD are at increased risk for comorbidity. With remission of PTSD symptoms, this increased risk for secondary diagnoses disappeared.
Animal and human research on neurobiological changes in the body’s stress response system after trauma suggests a physiological mechanism for the development of post-trauma affective disorder and PTSD (Garland et al., 2000; Heim and Nemeroff, 2001; Heim et al., 1997). Post-traumatic stress disorder involves unusual physiological and metabolic patterns of the major stress hormones such as cortisol and norepinephrine. The disorder further alters the serotonergic, dopamine, and opioid systems. Those with the diagnosis also suffer psychophysiological effects of trauma such as hyper-arousal and conditioned startle responses, and evidence abnormalities in the regions of the brain involved in memory and emotion (see van der Kolk, 1996). These same neurobiological pathways are consistently shown to be involved in substance use disorders (below), developmental trauma (Chapter 5), and in suicide (Chapter 4).
Approximately 2.2 million American adults (Narrow, unpublished, cited by NIMH) or about 1.1 percent of the population age 18 and older in a given year (Regier et al., 1993b) have schizophrenia. Schizophrenia affects men and women with equal frequency and has an onset in early adulthood (Robins and Regier, 1991). Symptoms of schizophrenia include delusions, hallucinations, disorganized speech, thought and movements. These are also termed “positive symptoms,” in that they are additional behaviors. Others, termed “negative symptoms” are the absence of normative behaviors such as flattened emotions or reduced spontaneous behaviors, social interaction, and volition (APA, 1994). Schizoaffective disorder includes periods of illness during which there is either a major depressive episode, a manic or mixed episode, concurrent with the criterion symptoms for schizophrenia. People with this disorder are often diagnosed with schizophrenia upon expression of those symptoms, making calculation of the prevalence as a separate disorder difficult. For the purpose of this report, those with either diagnosis will be referred to as those with schizophrenic disorders.