Background: It is estimated that around 6% of the danish population suffers from a func-tional disorder. It is often seen that these patients are send to several department of the healthcare system, in attempt to find a clear medical cause for the symptoms. Functional disorders typically bring along heavy consequences for the individual and large expense for society. The starting point of this master thesis is to provide information about the etiology of functional disorders by investigating the relationship with a potential predis-posing factor. Clearer knowledge about etiology will provide direction for future research and practical work with patients. Objectives: the main focus of the thesis is the examine the extent, to which sexual and physical abuse in childhood is predisposing for the devel-opment of functional disorders in adulthood. This will be done through two specific ques-tions, where the first will investigate the prevalence of childhood sexual and physical abuse in patients diagnosed with a functional disorder. The second question explores how stress is a potential mediating factor. Data sources: a systematic review using PsycInfo and PubMed in April 2021. Search terms included several designations of different func-tional diagnoses and words for childhood abuse. Study selection: selection criteria was, among others, quantitative studies including diagnosed functional disorder and reports of childhood abuse. An inclusion criterion involving measure for stress, was included later in the screening process. The selected articles were assessed for risk of bias. Results: the search and screening process resulted in 12 articles. 10 of these were case-control studies and the remaining two were cross-sectional studies. The included studies examined differ-ent functional diagnosis herein fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, chronic pelvic pain, functional vestibular syndrome and somatization disorder. The synthesis couldn’t provide evidence, that sexual and physical abuse was linked to functional disorders, due to conflicting results from the included articles. Furthermore, stress was measured through PTSD rating, perceived stress rating and neuroendocrine measurement. Results suggested that stress was dysregulated in the functional samples, and it was clear across almost all studies, that PTSD was increased in the functional sam-ples. Discussion: several points about methodology was discussed trying to understand why the present review found contradictory results, about childhood abuse and functional disorders, compared to former reviews. The definition of functional disorders was explor-ative in this thesis by uniting several organically unexplained diagnoses. This was dis-cussed, among other points. Furthermore, along with the evidence about dysregulated stress, it was discussed whether functional disorders are mediated by stress through a dysregulated HPA-axis and inappropriately cognitive mechanisms. The validity of the study was addressed in more ways. Conclusion: overall the present review couldn’t find evidence that sexual and physical abuse in childhood were a specific predisposing factor for the development of functional disorders. Although the review found evidence that stress, particular PTSD, was increased in functional disorders, discussing whether func-tional disorders are mediated by increased stress. Along with this, it was suggested that screening for traumatic experiences and PTSD in functional patients could be relevant. This should be invested in empirical studies together with the relation to stress overall.