The Role of Trauma History in the Relationship Between Schizotypy and Dissociation

Abstract
Childhood trauma is well established as a risk factor for schizophrenia-spectrum disorders. Updated models of psychosis etiology have proposed a pathway in which childhood trauma, mediated by dissociation, predicts later psychotic symptoms (Bloomfield et al., 2021; Khosravi, Bakhshani, & Kamangar, 2021). Existing research has demonstrated a mediating role of dissociation in patients with first-episode and chronic psychosis (Braehler et al., 2013). However, it is unclear why childhood trauma results in psychosis for some and not others. The current study examined the relationship between trauma history, schizotypy, and dissociation among a nonclinical population. Participants (n = 144) completed the Chapman Psychosis Proneness Scales (Chapman, Chapman, & Miller, 1982), as well as the Personality Disorder Interview-IV (Widiger, Mangine, Corbitt, Ellis, & Thomas, 1995) and MMPI-2-RF. Scores on the North Carolina Dissociation Index (Mann, 1995) were obtained from the MMPI-2-RF and the PDI-IV was qualitatively examined for history of trauma. Individual t-tests revealed significantly greater levels of dissociation for individuals with a history of trauma than those without (d = .52; p < .01), as well as significantly greater levels of dissociation in individuals identified as schizotypes (d = .36; p < .05). Next, we examined the relationship between schizotypy, trauma, and dissociation using a general linear model and found a significant additive effect of trauma on the relationship between schizotypy and dissociation (F = 4.3; p < .01). Our findings lend support to recent reports of a mediating role of dissociation for the relationship between childhood trauma and paranoid traits in nonclinical populations (Mertens, Racioppi, Sheinbaum, Kwapil, & Barrantes-Vidal, 2021). Whereas existing studies have used clinical or subclinical psychotic experiences as an outcome variable, this study suggests that the combination of trauma history and schizotypic personality organization predicts greater levels of dissociation than either trait by itself. These findings have potential implications for understanding the role of traumatic events and subsequent dissociative symptoms in predicting later psychosis in individuals who are at risk for schizophrenia-spectrum disorders.