Trauma and psychosis: theoretical and clinical implications

There are clearly complex and multiple relationships between trauma and psychosis (1). Psychosis can be a traumatic experience and have consequences for the individual that may be very similar to PTSD (2). It appears likely that, at least for some people, psychosis can be a reaction to traumatic experiences, given the prevalence of such experiences in people with psychosis, and the links in relation to form and content of psychotic experiences (3). For example, a consistent finding in research studies is that childhood sexual abuse seems to be specifically associated with the development of critical or commanding voices in adulthood (4). It is also important to note that in almost every country where surveys have been conducted, the public understands the causes of psychosis in terms of adverse psycho-social events and circumstances more so than biogenetic factors (5). They have continued to do so for decades, despite numerous campaigns designed to teach them that schizophrenia, for instance, is an illness like any other (6). Despite a recent increase in research devoted to this topic, there are relatively few studies that examine the mechanisms that may explain how trauma may increase vulnerability to psychosis. Recent psychological models of psychosis may help to explain the relationship between the experience of trauma and the development of psychotic experiences, and becoming a patient with a psychotic diagnosis. There may be several ways in which traumatic experiences may confer vulnerability to psychosis via cognitive and behavioural processes (1). It is also possible that the cognitive and behavioural consequences of trauma may make people vulnerable to psychosis. Negative beliefs about self, world and others (such as I am vulnerable and Other people are dangerous ) have been shown to be associated with the development of psychotic experiences (7–9). A recent study published in this issue has also shown that such beliefs specifically formed as a result of trauma are related to psychotic experiences in patients (10). Positive beliefs about psychotic experiences (such as paranoia is a helpful survival strategy ) may also be related to traumatic experience, and have shown to be associated with the development of psychosis (11). It is likely that psychotic experiences are essentially normal phenomena that occur on a continuum in the general population (12). It would seem that the occurrence of trauma in the life history of a person experiencing such phenomena may represent the difference between patients and non-patients (13). It appears that catastrophic or negative appraisals of psychotic experiences result in the associated distress (14, 15). In this context, the study in this issue of Bak et al. (16) is particularly welcome. Their large, prospective study of the general population found that there is a high prevalence of trauma in people who have psychotic experiences associated with distress whereas those without distress had a low prevalence of trauma. Therefore, consistent with predictions of cognitive models, trauma may predispose people to appraising their unusual experiences in a problematic way. In addition, the study by Roy and Janal (17), also published in the present issue, suggests that childhood trauma also affects likelihood of suicide attempts, and increased severity of trauma is associated with younger age of first attempt . This is clearly of relevance to people with psychosis, given the high prevalence of trauma and their increased risk of suicide (18). This research also highlights the need to ask service users about traumatic events in their life history. Currently, most child abuse cases, for example, remain undetected by mental heath services internationally (3). Furthermore there is some evidence that this is especially the case for people with diagnoses indicative of psychosis, and that mental health staff with strong biogenetic causal beliefs are particularly unlikely to ask about childhood trauma (19). We would, therefore, agree with the conclusion of Bak and colleagues that failing to ask about trauma will impede installation of appropriate treatment strategies and therefore, prolong distress unnecessarily. Bleuler (20) originally described the schizophrenias as a group of distinct psychotic disorders with Acta Psychiatr Scand 2005: 112: 327–329 All rights reserved DOI: 10.1111/j.1600-0447.2005. 00644.x Copyright 2005 Blackwell Munksgaard