Background: Early adversity scales often display insufficient content coverage and typically assess the presence of adversity, but not its severity.

Objective: To address some of these limitations, we developed the 13-item Youth and Childhood Adversity Scale. We subsequently revised and expanded the scale regarding content coverage and item wording, resulting in a 22-item version, which we here describe.

Methods: We conducted one cross-sectional (N = 1498; 43.9 % females; 24.42 years, SD = 3.72, range: 18–30 years) and one longitudinal study (N = 1084; 39.6 % females; 32 years, SD = 10.49, range: 18–75 years). To reflect the nature of the revised measure more accurately, it was named the Comprehensive Adversity Measure (CAM).

Results: Exploratory factor analysis suggested a one-factor model for both the presence/absence and the severity facet, which both displayed good model fit in subsequent confirmatory factor analyses. Factor models demonstrated at least scalar measurement invariance across gender and country (US/UK). Correlations with psychological distress, depression, anxiety, substance use, posttraumatic stress symptoms, obsessive-compulsive symptoms, suicide attempts, rumination, social comparison, self-esteem, and quality of life provided evidence in support of construct validity – concurrently and prospectively.

Conclusions: The CAM offers a psychometrically-sound, content-wise comprehensive, and free to use assessment of early adversity.