Sexual Trauma and Risk of Psychosis in Prodromal Population
Studies indicate a high prevalence of childhood trauma in patient cohorts with established psychotic disorder and in those at risk of developing psychosis. A causal link between childhood trauma and development of psychosis has been proposed. We aimed to examine the association between experience of childhood trauma and the development of a psychotic disorder in a large "Ultra High Risk" (UHR) for psychosis cohort. The data were collected as part of a longitudinal cohort study of all UHR patients recruited to research studies at the Personal Assessment and Clinical Evaluation clinic between 1993 and 2006. Baseline data were collected at recruitment to these studies. The participants completed a comprehensive follow-up assessment battery (mean time to follow-up 7.5 years, range 2.4–14.9 years), which included the Childhood Trauma Questionnaire (CTQ), a self-report questionnaire that assesses experience of childhood trauma. The outcome of interest was transition to a psychotic disorder during the follow-up period. Data were available on 233 individuals. Total CTQ trauma score was not associated with transition to psychosis. Of the individual trauma types, only sexual abuse was associated with transition to psychosis (P = .02). The association remained when adjusting for potential confounding factors. Those with high sexual abuse scores were estimated to have a transition risk 2–4 times that of those with low scores. The findings suggest that sexual trauma may be an important contributing factor in development of psychosis for some individuals.
Interest in the relationship between trauma and psychosis has been prompted by a number of research findings and clinical observations. First, the proportion of individuals with a psychotic disorder who have reported experiencing previous trauma is very high. Previous experience of trauma appears to be related to the severity of psychotic symptoms and has a negative impact on outcome and course of these disorders. Second, general population studies have demonstrated an association between early trauma and development of both psychotic-like experiences and psychotic disorder. This has led some authors to postulate an etiological role for trauma in the development of psychotic disorders.
Longitudinal studies are especially important to help address potential confounding factors in the observed cross-sectional relationship between previous trauma and psychosis. Given that the development of a psychotic disorder is a relatively rare event, cohort studies have often focused on psychotic symptoms and not on disorder. When studies have investigated psychotic disorder as an outcome, the number of available cases has been low and the measures used to diagnose psychosis relatively broad. The measures of trauma used in these studies have also been relatively crude in the context of large epidemiological studies. A number of research groups have investigated longitudinal prospective data on the outcome of childhood abuse in relation to developing a psychotic disorder. A group from Melbourne reported significantly higher odds of developing schizophrenia and other psychotic disorders in individuals who had documented childhood sexual abuse compared with a matched control population although there are null findings from this group. Janssen and colleagues reported an increased risk of later experiencing a psychotic disorder in a general population sample if individuals reported baseline childhood abuse (all abuse types). The populations and follow-up times in these studies are quite different, but they do suggest a possible relationship between early abuse and the development of a psychotic disorder. Indeed, a recent meta-analysis of a combination of study designs reported significant associations between adversity and psychosis with an overall effect of odds ratio = 2.78. The positive association was found for sexual abuse, physical abuse, bullying and emotional abuse but not for the death of a parent.
A population in which this association has not yet been well investigated is the "Ultra High Risk" (UHR) or putatively prodromal population. There may be important factors that are different in these individuals to population cohorts, eg, the fact they are seeking help from services for mental health problems. Recent research in clinical high-risk samples has demonstrated high rates of previous abuse in these patients. Our group has reported data suggesting an association between previous experience of sexual trauma specifically and subsequent "transition" to a frank psychotic disorder but not with overall trauma or other types of trauma. This was an interesting finding, but the study was conducted in a relatively small sample and only examined psychosis outcome over a short-term follow-up. Recent studies have demonstrated that the risk of psychotic illness is not limited to the first 12 months, and longer follow-up is necessary to thoroughly investigate the relationship between potential risk factors and development of psychosis. Our previous study also did not employ a structured participant-rated instrument of trauma.
In this study, we aimed to further investigate the relationship between experience of childhood/adolescent trauma and transition to psychotic disorder in an independent and much larger UHR sample, using a structured trauma instrument and with a longer follow-up period. Based on our previous finding, we hypothesized that sexual trauma specifically would predict transition to psychosis in this population.
Abstract and Introduction
Abstract
Studies indicate a high prevalence of childhood trauma in patient cohorts with established psychotic disorder and in those at risk of developing psychosis. A causal link between childhood trauma and development of psychosis has been proposed. We aimed to examine the association between experience of childhood trauma and the development of a psychotic disorder in a large "Ultra High Risk" (UHR) for psychosis cohort. The data were collected as part of a longitudinal cohort study of all UHR patients recruited to research studies at the Personal Assessment and Clinical Evaluation clinic between 1993 and 2006. Baseline data were collected at recruitment to these studies. The participants completed a comprehensive follow-up assessment battery (mean time to follow-up 7.5 years, range 2.4–14.9 years), which included the Childhood Trauma Questionnaire (CTQ), a self-report questionnaire that assesses experience of childhood trauma. The outcome of interest was transition to a psychotic disorder during the follow-up period. Data were available on 233 individuals. Total CTQ trauma score was not associated with transition to psychosis. Of the individual trauma types, only sexual abuse was associated with transition to psychosis (P = .02). The association remained when adjusting for potential confounding factors. Those with high sexual abuse scores were estimated to have a transition risk 2–4 times that of those with low scores. The findings suggest that sexual trauma may be an important contributing factor in development of psychosis for some individuals.
Introduction
Interest in the relationship between trauma and psychosis has been prompted by a number of research findings and clinical observations. First, the proportion of individuals with a psychotic disorder who have reported experiencing previous trauma is very high. Previous experience of trauma appears to be related to the severity of psychotic symptoms and has a negative impact on outcome and course of these disorders. Second, general population studies have demonstrated an association between early trauma and development of both psychotic-like experiences and psychotic disorder. This has led some authors to postulate an etiological role for trauma in the development of psychotic disorders.
Longitudinal studies are especially important to help address potential confounding factors in the observed cross-sectional relationship between previous trauma and psychosis. Given that the development of a psychotic disorder is a relatively rare event, cohort studies have often focused on psychotic symptoms and not on disorder. When studies have investigated psychotic disorder as an outcome, the number of available cases has been low and the measures used to diagnose psychosis relatively broad. The measures of trauma used in these studies have also been relatively crude in the context of large epidemiological studies. A number of research groups have investigated longitudinal prospective data on the outcome of childhood abuse in relation to developing a psychotic disorder. A group from Melbourne reported significantly higher odds of developing schizophrenia and other psychotic disorders in individuals who had documented childhood sexual abuse compared with a matched control population although there are null findings from this group. Janssen and colleagues reported an increased risk of later experiencing a psychotic disorder in a general population sample if individuals reported baseline childhood abuse (all abuse types). The populations and follow-up times in these studies are quite different, but they do suggest a possible relationship between early abuse and the development of a psychotic disorder. Indeed, a recent meta-analysis of a combination of study designs reported significant associations between adversity and psychosis with an overall effect of odds ratio = 2.78. The positive association was found for sexual abuse, physical abuse, bullying and emotional abuse but not for the death of a parent.
A population in which this association has not yet been well investigated is the "Ultra High Risk" (UHR) or putatively prodromal population. There may be important factors that are different in these individuals to population cohorts, eg, the fact they are seeking help from services for mental health problems. Recent research in clinical high-risk samples has demonstrated high rates of previous abuse in these patients. Our group has reported data suggesting an association between previous experience of sexual trauma specifically and subsequent "transition" to a frank psychotic disorder but not with overall trauma or other types of trauma. This was an interesting finding, but the study was conducted in a relatively small sample and only examined psychosis outcome over a short-term follow-up. Recent studies have demonstrated that the risk of psychotic illness is not limited to the first 12 months, and longer follow-up is necessary to thoroughly investigate the relationship between potential risk factors and development of psychosis. Our previous study also did not employ a structured participant-rated instrument of trauma.
In this study, we aimed to further investigate the relationship between experience of childhood/adolescent trauma and transition to psychotic disorder in an independent and much larger UHR sample, using a structured trauma instrument and with a longer follow-up period. Based on our previous finding, we hypothesized that sexual trauma specifically would predict transition to psychosis in this population.
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