Epigenetics and first-episode psychosis: A systematic review

•Psychosis has a huge impact globally in regards to both quality of life as well as healthcare costs.•Several risk factors have already been identified, including substance use, paternal age, and trauma history.•This literature review examined epigenetic effects on first-episode psychosis.•Seventeen studies were included in this literature review and several epigenetic alternations were found. Many reviewed studies looked at alterations in the LINE-1 portion of the genome; however, the results were not consistent. Therefore, more research is needed in this area to clarify changes and then be able to translate this data in a clinically practical manner.