CLINICAL HANDBOOK OF SCHIZOPHRENIA

452 VI. SPECIAL POPULATIONS AND PROBLEMSor situations that are reminders of the trauma, which leads to further vigilance andavoidant behavior. In addition, some traumatic events are so overwhelming that survivors’assumptions about the world (e.g., “People are mostly OK”) and themselves (“Iknow how to look out for danger as well as the next person”) can be shattered. They mayconstruct new cognitive frames or internal scripts that keep them locked in aspects of thetraumatic moment (e.g., “I could be attacked at any moment” or “No one can betrusted”).The severity of the trauma, the number of traumas to which persons have been exposedin their lifetime, the nature of available social supports, and the quality known aspsychological hardiness, or resilience, all influence the likelihood of developing PTSD followingexposure, as well as the severity and chronicity of this disorder. All these factorsseem to conspire to make people with schizophrenia highly vulnerable to developingchronic PTSD.Recent estimates of lifetime prevalence of PTSD in the general population range between8 and 12%, and the few available, community-based studies reporting point prevalenceof PTSD (the number of people who meet diagnostic criteria on any given day) suggestrates of approximately 2%: 2.7% for women and 1.2% for men. Studies of clientswith severe mental illness suggest much higher rates of PTSD. Seven studies have reportedcurrent rates of PTSD ranging between 29 and 43% (Mueser, Rosenberg, Goodman, &Trumbetta, 2002), yet PTSD, as discussed earlier, was rarely documented in clients’charts. In the few studies with samples large enough to assess PTSD in clients by diagnosis,clients with schizophrenia spectrum diagnoses had slightly lower rates (33%) than clientswith mood disorders (45%), but rates in both groups were nevertheless much higherthan those in the general population. Another study reported that among persons hospitalizedfor a first episode of psychosis, 17% met criteria for current PTSD. This study, incombination with the others, suggests that childhood trauma exposure and PTSD notonly occur more often in persons who develop schizophrenia and other forms of severemental illness, but that having severe mental illness also increases subsequent risk fortrauma and PTSD. As in the general population, PTSD severity in clients with severemental illness is related to severity of trauma exposure, and the high rates of PTSD in thispopulation are consistent with clients’ increased exposure to trauma. These rates alsosuggest an elevated risk for developing PTSD given exposure to a traumatic event. Forexample, in a sample of clients drawn from a large health maintenance organization,Breslau, Davis, Andreski, and Peterson (1991) reported that the prevalence of PTSDamong those exposed to trauma was 24%. This rate of PTSD following trauma exposureis approximately half the rate (47%) found in studies of trauma and PTSD in personswith severe mental illness. The high PTSD rate in this population and its correlation withworse functioning suggests that PTSD may interact with the course of co-occurring severemental illnesses, such as schizophrenia and major mood disorders, worsening the outcomeof both disorders. We developed a model to help us understand how trauma andPTSD may interact with schizophrenia and other severe mental illnesses (see Figure 43.1).TRAUMA, PTSD, AND THE COURSE OF SCHIZOPHRENIAThis model describes how PTSD directly and indirectly mediates the relationships amongtrauma, more severe psychiatric symptoms, and greater utilization of acute care servicesin clients with schizophrenia (Mueser et al., 2002). Specifically, we suggest that the symptomsof PTSD may directly worsen the severity of schizophrenia due to clients’ avoidanceof trauma-related stimuli (resulting in social isolation), reexperiencing the trauma (resulting