Unraveling the Concept of Childhood Adversity in Psychosis Research: A Systematic Review.

Background: During the last decades, an abundance of studies has investigated childhood adversity in relation to psychosis. This systematic review critically examines the methodologies employed to investigate childhood adversity in psychosis over the past decade, including operational definitions, measurement tools and characteristics, and psychometric properties of instruments used in these studies.

Study design: This systematic review followed the PRISMA guidelines (registration number CRD42022307096), and the search used the following electronic databases: PsychINFO, SCOPUS, Web of Science, African Index Medicus (AIM), LILACS, CINAHL, EMBASE, and MEDLINE. The search included variations and combinations of the terms targeting childhood adversity and psychosis.

Study results: Out of 585 identified studies published between 2010 and 2023, 341 employed a validated instrument to investigate childhood adversity. Our findings show "childhood trauma" being the most frequently examined construct, followed by "child maltreatment" or "child abuse." The short version of the Childhood Trauma Questionnaire was the dominant instrument. Physical abuse, emotional abuse, and sexual abuse were most frequently investigated, and indeed the field appears generally to focus on child abuse and neglect over other adversities. Significant psychometric heterogeneity was observed in the selection and summarization of instrument items, with only 59% of studies documenting original psychometric validation and 22% reporting reliability in their datasets.

Conclusion: This review highlights substantial methodological heterogeneity in the field, pointing out biases in the research on childhood adversity and psychosis. These findings underline the need for standardized definitions and high-quality measurement tools to enhance the validity of future research in this area.