Childhood sexual abuse increases risk of auditory hallucinations in psychotic disorders
Introduction
It is well established that individuals with mental illness report a higher prevalence of childhood trauma than those without, suggesting that the experience of trauma during childhood can increase the risk of developing a psychiatric disorder [1]. To understand the nature of this relationship, recent studies have examined the association between childhood trauma and specific symptoms of mental illness, such as psychosis, and many have reported a significant link [2], [3], [4], [5], [6]. One of the most consistent findings across multiple studies is the greater risk for hallucinations after childhood abuse [7], [8], [9], with some studies pointing to childhood sexual abuse as a specific risk factor for the experience of auditory hallucinations [10], [11], [12].
However, two recent review articles have questioned the reliability and implications of these studies [13], [14]. One limitation is the lack of a quantitative measure of childhood abuse which systematically assesses multiple domains of trauma (sexual, physical, emotional). For example, some studies have determined rates of abuse through review of the medical records of psychiatric patients [12], [15] while others have used surveys with a small array of general lifetime trauma questions [4], [5], [7], [9], leading to reports of childhood abuse that may not be assessed in a standardized way. On the other hand, many studies reporting a relationship between childhood sexual abuse and psychosis have focused solely on past sexual abuse, not assessing for any co-occurring physical or emotional abuse, leaving out possible confounding factors [3], [11], [16]. A final problem has been the lack of a control group for comparison of baseline rates of abuse. In their review, Bendall and colleagues argue that establishing a higher prevalence of childhood trauma in psychotic patients, as compared to a healthy control group, is a critical first step in finding an association between trauma and psychosis [13]. They state that using the same methods across subjects, researchers must first find higher rates of childhood trauma in individuals with psychosis than healthy controls, in order to make a reasonable argument that trauma is a risk factor for psychosis.
In the time since these reviews were published, more methodologically rigorous studies have worked to address these shortcomings and establish a stronger relationship between abuse and psychosis. Two studies found a dose–response relationship between the experience of trauma and risk for psychotic experiences [17], [18], comparing psychotic experiences prospectively [18] and comparing psychosis patients with siblings and healthy controls [17]. In addition, a recent study found a specific relationship between childhood sexual abuse and transition to psychosis within an ultra-high risk group, with an estimated 2–4 times greater risk of transition to psychosis in individuals with high sexual abuse scores compared to those with low sexual abuse [19].
In the current study we add to this growing literature by addressing several of the previous limitations. Our experimental sample includes a large group of well-characterized patients with a psychotic disorder and demographically-similar control participants. In addition, all subjects received the CTQ, a valid and reliable measure of childhood abuse [20], [21], [22] that assesses five different kinds of abuse on a continuous scale, allowing us to test the relationship between each abuse type and different psychotic symptoms. Here we test the hypotheses that severity of childhood abuse is greater in psychotic disorder patients compared to healthy controls and that childhood sexual abuse increases the risk of experiencing auditory hallucinations in psychotic disorder patients.
Section snippets
Subjects
Participants included 114 psychotic disorder patients (53 with schizophrenia, 28 with schizoaffective disorder, and 33 with bipolar disorder, type 1, with psychotic features) and 81 healthy controls. All participants completed written informed consent after approval of the study protocol by the Vanderbilt University Institutional Review Board, Nashville, Tennessee. Psychotic patients were recruited from the inpatient unit and outpatient clinic of the Vanderbilt Psychiatric Hospital, and healthy
Results
Consistent with previous studies, patients with a psychotic disorder reported significantly more overall childhood abuse than healthy control subjects (CTQ Total: F(1, 193) = 70.10, p < .001). A similar pattern was observed for each of the five sub-scales of childhood abuse (physical abuse: F(1, 193) = 30.13, p < .001; sexual abuse: F(1,193) = 39.34, p < .001; emotional abuse: F(1, 193) = 69.75, p < .001; emotional neglect: F(1, 193) = 44.08, p < .001; physical neglect: F(1, 193) = 34.09, p < .001) (for means, see
Discussion
We found that psychotic disorder patients experienced elevated rates of childhood trauma across all domains measured by the CTQ, relative to demographically-similar healthy control participants, which is consistent with previous research [3], [17], [32]. This confirms that all types of childhood abuse put individuals at risk for the development of a serious psychiatric disorder [1], [15], [33], [34]. We also found that psychotic disorder patients who experience auditory hallucinations report
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