Abstract

Over the last decades, childhood maltreatment has emerged as a major risk factor for the development and maintenance of transdiagnostic psychopathology. Notably, higher prevalence rates of maltreatment have been found for nearly all mental disorders, with particularly high numbers for post-traumatic stress disorder, depression, borderline personality disorder and anxiety disorders. Furthermore, childhood maltreatment has been associated with an earlier onset of mental disorders, a more severe and chronic course of disease as well as reduced rates of psychological treatment benefit. However, the pathways that underlie this relationship are still unknown. It has been shown that various factors, for example biological alterations, play a role in the relationship between childhood maltreatment and mental disorders. Research investigating the influence of psychological factors, such as emotional reactivity and emotional regulation, attachment or post-traumatic stress symptoms is rare. These investigations are highly relevant in order to identify potential targets for psychological interventions. First approaches in this line of research examine specific transdiagnostic treatments for early traumatization, such as Imagery Rescripting. However, as childhood maltreatment is suspected to be associated with a broad array of mental disorders, it might not be explained by a single underlying mechanism. Instead, multiple pathways are probable to mediate the relationship between childhood maltreatment and transdiagnostic psychopathology. Therefore, the major aim of this thesis is to make a first step in filling this research gap by investigating the underlying psychological mechanisms between childhood maltreatment and psychopathology in clinical studies. Studies I and II were conducted with a clinical sample (N= 69) of patients with obsessive compulsive disorder (OCD). Preliminary research, though limited by small sample sizes and inconsistent findings, showed that childhood maltreatment might play a role in OCD. In order to replicate and expand on these findings we aimed to examine the association of childhood maltreatment and OCD more closely. Study I primarily examined the subtypes of childhood maltreatment influencing OCD and additionally the impact of childhood maltreatment on the success of psychological OCD treatment (immediately following treatment and at 6 months post). We found three main results: First, increased prevalence rates of childhood maltreatment among our OCD patient sample in comparison to a general German population sample. Second, childhood maltreatment severity was related to greater OCD symptom severity, with the most robust relationship for the maltreatment subtype of emotional abuse. Third, individuals with higher levels of childhood maltreatment reported greater OCD symptoms at pre-treatment, post-treatment, and 6 months after their inpatient stay, compared to patients without maltreatment experiences. However, in contradiction of our hypothesis, childhood maltreatment did not influenced treatment benefit. Based on the findings, study II aimed to examine the underlying mechanisms of the detected association between childhood maltreatment and OCD symptoms. Potential mediating factors were chosen based on the following criteria: (a) evidence for association with childhood maltreatment, (b) evidence for association with OCD, and (c) existing plausible theoretical explanation for this mediator as an underlying mechanism. Therefore, we predicted that, emotion regulation difficulties, rumination, an insecure attachment style, dissociation, and post-traumatic stress symptoms are potential mediators between the association of childhood maltreatment and OCD symptom severity. In line with our hypotheses, these factors all mediated the relationship between childhood maltreatment and OCD symptom severity. However, regarding insecure attachment styles, the subtype of avoidant attachment was not linked to either childhood maltreatment or OCD symptom severity, suggesting that in OCD an anxious attachment is more prominent. Study III investigated the specific role of emotional reactivity as an underlying mechanism between childhood maltreatment and major depression in a clinical sample of patients with major depression (N= 69). Whereas in the literature for major depression the findings regarding heightened emotional reactivity are inconsistent, childhood maltreatment was widely associated with increased emotional reactivity. We therefore hypothesized that the severity of childhood maltreatment is related to higher emotional reactivity among depressive patients. Hence, self-reported and physiological emotional reactivity was measured while presenting audio recordings with neutral, negative and individualized childhood trauma-related scripts (so called script imagery method). In line with our hypothesis, depressive patients with higher levels of childhood maltreatment reported heightened emotional reactivity to the childhood trauma-related script and the negative script compared to the neutral script. In particular, they rated the negative script as more aversive and distressing. Additionally, they showed more re-experiencing and dissociation experiences in response to the negative script. Equally, the trauma-related script was perceived as more aversive and distressing. Furthermore, it resulted in greater levels of arousal and showed more avoidance as an emotional regulation strategy. In contrast to our hypothesis, no effect of childhood maltreatment on physiological responsiveness emerged. Overall, there is a growing body of literature showing that childhood maltreatment is a transdiagnostic risk factor for various mental disorders. However, few researchers have addressed the question of how this early vulnerability to psychopathology develops and persists. This thesis aimed to expand on current knowledge of the underlying pathways of the relationship between childhood maltreatment and psychopathology in two different mental disorders. The study findings presented in this thesis provide first evidence that heightened emotional reactivity (but not psychophysiological reactivity) and difficulties in emotion regulation, together with rumination might play a role. Moreover, post-traumatic stress symptoms, even those deemed subclinical, such as hyperarousal, avoidance and dissociative symptoms might be mediating factors between childhood maltreatment and transdiagnostic psychopathology. Since we found indications that re-experience might also play a role in mediating this relationship, future work will concentrate on exploring this factor in more detail. Additionally, further work is needed to investigate the cause of high divergence between self-report emotional reactivity and psychophysiological reactivity. From a methodological perspective, problems in assessing childhood maltreatment retrospectively with the childhood trauma questionnaire will be discussed. Moreover, implications for a theoretical transdiagnostic model and methodological approaches, as well as directions for future research on the underlying pathways of childhood maltreatment and psychopathology are outlined.