Emotion regulation as a transdiagnostic construct : novel approaches to psychiatric diagnostics

Sammanfattning: Diagnostic co-occurrence among mental health problems is common. It has been suggested that more research which incorporates analysis on the symptom level and cuts across categorical diagnostic boundaries is needed. This type of transdiagnostic research could have the potential to further increase our understanding of psychopathology and how we can improve treatment outcomes. Emotion regulation is one transdiagnostic process which is thought to be of relevance to several types of mental health problems. These problems include eating disorders and substance use disorders, two areas that both show a significant overlap and are associated with emotion regulation difficulties. The current thesis thus aimed to contribute to the further understanding of (a) symptom-level change and (b) measurement of emotion regulation and its role across different levels of mental health problems (with a focus on eating- and substance use disorders). The aim of Study I was to investigate symptom change over time, by assessing if treatment-seeking adults with eating disorders (N = 3159) demonstrated “symptom shifting” (simultaneously decreasing in some symptoms whilst increasing in others). Individuals demonstrating symptom shifting were then compared to nonshifting individuals on various indicators of mental illness. In the sample, 13% were found to demonstrate symptom shifting among eating disorder-related behaviors. The proportion of patients with symptom shifting increased to 19% when including shifts to deliberate self-harm or substance use (in addition to eating disorder-related behaviors). Individuals with symptom shifting reported significantly higher levels of other psychiatric symptoms (such as depression and anxiety), clinical impairment, and emotion regulation difficulties compared to nonshifting individuals. It was concluded that individuals with symptom shifting could be a group in need of tailored monitoring in clinical practice, as well as treatment approaches targeting several types of risky behaviors. The aim of Study II was to further investigate symptom change over time, by investigating if symptom shifting occurred between symptoms of eating- and substance use disorders in a general population sample (N = 3315). Individuals with symptom shifting were also compared to other individuals with different temporal symptom profiles. A small group of individuals (2% of the whole sample) demonstrated symptom shifting (which represented 10% of individuals who suffered persistent problems in any or both areas). Individuals with symptom shifting reported higher levels of psychiatric symptoms (such as depression, anxiety, suicidality) and demonstrated higher polygenic risk scores for psychiatric disorders. Levels were comparable to individuals who suffered persistent co-occurring problems with eating- and substance use disorder symptoms over time. The results contribute to the understanding of the overlap between eating- and substance use disorders, and again highlight the need for health care services and treatments that address several problem areas simultaneously. The aim of Study III was to evaluate psychometric properties and contrast two of the most used measures of emotion regulation, for which a community sample of adults residing in the US was used (N = 843). The Emotion Regulation Questionnaire (ERQ) and the Difficulties in Emotion Regulation Scale (DERS; including its short form DERS-16) were evaluated using correlations and confirmatory factor analyses. The measures were found to converge in expected ways. Satisfactory fits were found for the ERQ and DERS- 16, but not for the original DERS. The DERS showed greater concurrent validity with psychiatric symptoms (depression, anxiety, stress, substance use) than the ERQ. It was concluded that the validity of both measures to assess emotion regulation was supported, and that the DERS-16 with its shorter format is a clinically useful tool to assess emotion regulation in practice. The aim of Study IV was to investigate the relationship between emotion regulation difficulties across different levels of substance use, and the role of co-occurring psychiatric symptoms. Data from two main sources were used, including the community sample in Study III (n = 843) and two substance use disorder populations from residential treatment clinics in the US (n = 415). Emotion regulation was significantly associated with both substance use frequency and severity across a variety of substances. Of the different facets of emotion regulation (DERS subscales), difficulties controlling impulsive behaviors was found to be specifically associated with greater substance use severity. No significant moderating effect of psychiatric symptoms (depression, anxiety, stress) was found. Results suggested that emotion regulation difficulties are of increasing relevance across the spectrum of substance use, from no use, to misuse, to poly-substance dependence. The studies could contribute to method development in the area of symptom-level change and furthers our understanding of emotion regulation as a relevant transdiagnostic construct. They also could contribute by highlighting important clinically relevant outcomes (such as symptom shifting), which could have potential implications in psychiatric research and clinical practice/health care. Studying common functions of risky behaviors, such as eating disorder-related behaviors, substance use, and deliberate self-harm, from an emotion regulation perspective is suggested to be of importance to consider in future research.