Young girls at familial high risk of developing anorexia nervosa - An examination of potential neuropsychological, psychiatric and neurobiological premorbid markers

Abstract

Anorexia nervosa (AN) is a severe psychiatric disorder with specific impacts on neuropsychological, psychiatric and neurobiological functions. The aim of this thesis was to examine young girls at familial high risk (FHR) of developing AN to detect potential premorbid risk factors with similarities to the manifestations of ongoing AN. If similar signs can be detected among girls at FHR for AN, these may constitute underlying vulnerabilities, or markers, potentially increasing the risk of AN. Studies I-IV all belonged to the same cohort, consisting of biological daughters, six to twelve years of age, whose mothers had a history of AN. In total, 28 FHR daughters were recruited to the study together with their mothers (AN mothers). An age-matched group of 42 comparison (COMP) daughters without FHR for AN were recruited along with their mothers (COMP mothers). In study I, neuropsychological profile, including set-shifting and central coherence, was examined among the FHR and COMP daughters. Study II was based on structural and functional magnetic resonance imaging (MRI) data from both daughters and mothers. In study III, the prevalence of psychiatric morbidities was assessed among the FHR and COMP daughters. Study IV used blood samples to measure concentrations of the appetite hormones ghrelin and AgRP and the inflammatory markers IL-1β, IL-6, IL-8 and TNF-α in the FHR and COMP daughters. Largely, the results did not provide evidence for premorbid neuropsychological or neurobiological markers. Specifically, no differences in neuropsychological profile, structural and functional brain parameters or biomarkers in blood were detected between the FHR and COMP daughters. However, the risk of having at least one psychiatric diagnosis was 27 percentage points higher for the FHR daughters, thus significantly increased in contrast with the COMP daughters. The most common diagnoses among the FHR daughters were anxiety disorders and autism. In addition, the FHR daughters had significantly elevated emotional symptoms in contrast to the COMP daughters. In conclusion, this is the first and most extensive FHR study for AN conducted to date. According to the findings, only limited evidence could be provided for premorbid markers among daughters at FHR for AN. However, the relatively limited sample size may have prevented the detection of differences between the groups. The most robust finding included the increased risk of psychiatric diagnoses in the FHR daughters. Potentially, psychiatric symptoms in childhood may represent a premorbid vulnerability among individuals at FHR for AN, subsequently increasing the risk of full-blown AN development. A follow-up study will be required to further elucidate the role of psychiatric morbidities and other factors as potential predictors for AN.