Objective: Depersonalization and derealization (DP & DR) are more prevalent amongst persons with anxiety, depressive, and personality disorders, as well as those experiencing negative factors...Show moreObjective: Depersonalization and derealization (DP & DR) are more prevalent amongst persons with anxiety, depressive, and personality disorders, as well as those experiencing negative factors in their daily life (such as sleep deprivation, exhaustion, drug and alcohol abuse, and stress). As these negative factors are also more prevalent in the aforementioned disorders, this study examines whether these factors account for the relationship of these disorders and their corresponding symptoms with DP & DR. Method: A dataset of mental help seeking individuals (N=1008), gathered through a screener questionnaire by GPs in the west of the Netherlands, was used to assess the hypothesis from both a traditional nosological approach (using disorder indications) and a dimensional/symptom-oriented approach (using symptom severity). From a nosological perspective, AN(C)OVAs were performed where DP&DR in disorder groups was compared to a control group also after controlling for the following factors of impact (FOI): sleep deprivation, exhaustion, drug and alcohol abuse, and stress. From a dimensional perspective, multiple stepwise regression analyses were performed in which DP&DR was predicted by symptom severity, also after controlling for the FOI. Results: We found that DP&DR was elevated in depressive, anxiety and comorbid disorders (but not in personality disorder) and also that anxiety, depressive, and personality disorder symptom severity was associated with DP&DR. The unique associations between disorder groups and symptom severity was greatly attenuated by controlling for the FOI. Conclusions: The results yield support for FOI being partly responsible for the association between common mental disorders and symptom severity with DP & DR.Show less