Insomnia disorder (ID) is a prevalent stress-related sleep disorder involving burdening symptoms related to emotional disturbances. This paper introduces a higher-order adaptive dynamical system model to explore the potential role of epigenetic mechanisms in the development and persistence of ID. The model examines how epigenetic modifications, particularly in genes related to mechanisms of the sleep-wake regulation and stress response systems, may potentially contribute to the pathology of ID. Results of simulations of the model are reported in this study to underscore the complexity of ID as a dynamic and (mal-)adaptive system of emotion regulation and sleep-wake-regulation processes.