The differential effects of child abuse and posttraumatic stress disorder on schizotypal personality disorder

Abstract

Objective

Previous findings suggest a relation between trauma exposure and risk for schizotypal personality disorder (SPD). However, the reasons for this relationship are not well understood. Some research suggests that exposure to trauma, particularly early trauma and child abuse, as well as posttraumatic stress disorder (PTSD) may play a role.

Methods

We examined subjects (n = 541) recruited from the primary care clinics of an urban public hospital as part of an National Institute of Mental Health-funded study of trauma-related risk and resilience. We evaluated childhood abuse with the Childhood Trauma Questionnaire and the Early Trauma Inventory and SPD with the Schedule for Nonadaptive and Adaptive Personality. We assessed for lifetime PTSD using the Clinician-Administered PTSD Scale.

Results

We found that of the 3 forms of abuse analyzed (emotional, physical, and sexual), only emotional abuse significantly predicted SPD (P < .001, R = 0.28) when all 3 abuse types were simultaneously entered into a regression model. Lifetime PTSD symptoms also significantly predicted SPD (P < .001, R = 0.26). Posttraumatic stress disorder was specifically predictive of 4 of the 8 SPD symptoms (P ≤ .001): excessive social anxiety, a lack of close friends or confidants, unusual perceptual experiences, and eccentric behavior or appearance. Using a Sobel test, we also found a partial mediation effect of PTSD on the relation between emotional abuse and SPD (z = 3.45, P < .001).

Conclusions

These findings point to the important influence of emotional abuse on SPD and suggest that PTSD symptoms may provide a link between damaging childhood experiences and SPD symptoms in traumatized adults.

Introduction

Studies have shown that childhood (emotional, physical, and sexual) abuse is associated with many long-term psychological effects, including substance abuse, depression, suicidality, and personality disorders (PDs) [1], [2]. However, the specific mechanisms accounting for the relationship between childhood abuse and these negative mental health outcomes are not fully understood. Evidence suggests that posttraumatic stress disorder (PTSD) may be one pathway linking childhood abuse and later psychopathology. Early childhood trauma increases risk for additional trauma exposure as an adult and also increases one's likelihood of developing PTSD as a result of a subsequent trauma [3], [4]. Researchers have also found a dose-response relationship between lifetime level of trauma exposure and risk for the development of PTSD [4], [5], [6]. One explanation that has been offered to account for the relationship between childhood abuse and the wide range of associated mental health problems is that this risk is partially accounted for by PTSD among adults with a history of childhood abuse. Some studies suggest that PTSD symptoms mediate the relationship between early childhood trauma exposure and risk for adult psychopathology [7], [8]. For example, some recent research suggests that the relationship between childhood abuse and risk for substance use as an adult is accounted for by attempts to “self medicate” PTSD symptoms using drugs and alcohol [9].

Recently, there has been a particular focus on understanding how childhood abuse may increase the risk of developing PDs in adulthood. A community-based study by Johnson et al [10], [11] showed that individuals who experienced childhood abuse or neglect were more than 4 times as likely to develop a PD in early adulthood. The investigators also found that verbal (ie, emotional) abuse predicted PD symptoms in adolescence and adulthood, even after controlling for other forms of child abuse and co-occurring psychiatric disorders [10]. Specifically, this study found that emotional abuse was associated with increased risk of elevated borderline, narcissistic, paranoid, schizoid, and schizotypal PD (SPD) symptom levels in adolescence and early adulthood. Ruggiero et al [12] also found a link between child abuse and risk for PDs in their sample of male VA patients. Their results demonstrated that different patterns of childhood abuse and neglect related to different PDs, suggesting more than a general association between childhood maltreatment and PDs. These studies investigated the overall relationship between childhood abuse and later development of any of the 10 PDs outlined in the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV) [13]. They did not focus on the relationship between abuse and risk for any specific PD. Therefore, these studies do not clarify to what degree childhood abuse may be associated with the characteristics of any one PD (eg, self-harm as a symptom of borderline PD or unusual perceptual experiences as a symptom of SPD) as opposed to increased risk for factors that are common across PDs (eg, interpersonal difficulties).

Some research has focused particularly on the association between SPD and child abuse. An increasing body of research indicating an association between history of childhood trauma and increased risk for adult psychotic symptoms [5], [14], [15] has led researchers to investigate the specific association between the development of SPD symptoms and childhood abuse. SPD is one of the most controversial of the 10 DSM-IV PDs, with some research suggesting that SPD should not exist as a distinct disorder [16], [17] and some discussion of removing SPD as a diagnostic category in the fifth edition of DSM. Instead, researchers have suggested that the eccentric symptoms that seem to set SPD apart may be better understood as a trait modifier for other PDs [18]. There is also evidence that SPD's unique symptoms could be represented through a specific pathologic personality trait (ie, peculiarity) [19]. Research has consistently shown that high rates of comorbidity exist among the 10 PDs, especially within the same DSM-IV PD clusters [20]. With existing research suggesting that change to the current diagnostic setup of PDs is necessary, understanding how the specific symptoms of schizotypy may be influenced by traumatic life events is particularly relevant.

Accumulating evidence supports the hypothesis that early trauma exposure increases the risk of developing peculiar perceptions and beliefs [21]. Berenbaum et al [22] found that childhood maltreatment was associated with elevated levels of cognitive-perception SPD symptoms (eg, ideas of reference, magical thinking, unusual perceptual experiences, and paranoid ideation) and with SPD in general. Consistent with previous findings [10], a follow-up study by Berenbaum et al [21] showed emotional abuse related to SPD most strongly, even when controlling for other forms of maltreatment. In addition, the investigators found that PTSD acted as a partial mediator of the association between childhood maltreatment and SPD [22], suggesting that PTSD may represent one pathway in which child abuse translates into SPD. These researchers posit that developing peculiar beliefs or perceptions may provide a way of coping with trauma, like childhood abuse. However, they indicate that additional research on the role of PTSD is needed.

The similar (and sometimes overlapping) nature of PTSD and psychosis and their co-occurrence in trauma survivors need to be taken into account in understanding any potential relation between child abuse, PTSD, and psychotic-spectrum disorders, including SPD. Recent reviews on the relationship of psychotic symptoms and PTSD-associated symptoms suggest that the links between symptoms of PTSD (eg, reexperiencing, flashbacks, dissociation) and psychotic symptoms are multideterminant [5], [23]. Some argue that the association between psychosis and high rates of trauma exposure understandably leads to high comorbidity with PTSD and that PTSD may act as an indicator of more severe mental illness in such cases [8]. Dissociative experiences often characteristic of PTSD can also increase one's vulnerability to psychotic-like symptoms later in life [5]. Another possibility is that they represent similar entities and therefore operate on a continuum of reactions to extreme stress. However, research indicates that comorbid PTSD and secondary psychosis are not associated with a family history of psychotic disorder, suggesting that PTSD and psychosis may not share common underlying genes [24]. These reviews further suggest that it is likely that different processes vary across individual cases.

Only limited research has explored the complex relationship between several types of childhood abuse, lifetime PTSD symptoms, and SPD. If PTSD symptoms, regardless of whether they are a direct result of child abuse, are a mechanism linking child abuse and SPD, this suggests the important role that both early abuse and PTSD symptom may play in exacerbating schizotypy. Thus, the goal of this article is to examine the potential relationship among these variables in a highly traumatized population. Specifically, the current study will explore (1) how each form of childhood abuse influences the development SPD, (2) if the presence of lifetime PTSD symptoms has a mediating effect on the association between SPD and childhood abuse, and (3) if certain symptoms of SPD are relevant to these relationships.