Aggression in prison populations by gender and security Level: An analysis using the personality assessment Inventory Espinoza-Gárate, Pablo Quevedo Blasco, Raúl Rubén López Vallejo, Sofía Burneo Garcés, Carlos Inmates Violence Psychopathology The authors would like to thank the Health Coordination Zone 8 (Ministry of Public Health of Ecuador) for supporting and partially funding this study, along with the Undersecretariat of Rehabilitation, Reintegration, and Precautionary Measures for Adults (Ministry of Justice, Human Rights, and Cults of Ecuador) for issuing permits; the authorities of the Regional Guayas Social Rehabilitation Center and Guayaquil Social Rehabilitation Center for the facilities offered to develop the fieldwork; and the team of psychologists from the Health Coordination Zone 8 and Health Coordination Zone 5 for the fieldwork conducted. In addition, this work was partially supported by the Regional Ministry of Economy, Innovation, and Science from the Andalusian Government (Project: P2012-SEJ1723) and the Spanish Ministry of Economy and Competitiveness (Project: PSI2013-42792-R). The opinions and conclusions expressed in this article do not reflect any official policy or position of any of these institutions. Aggressive behaviors of varying severity and lethality are frequently reported in prison populations. However, the lack of comprehensive studies including both male and female samples limits current understanding of gender-based similarities and differences in psychological, psychopathological, and criminogenic variables. This study aimed to explore aggression-related traits —specifically the Aggression (AGG) scale and its subscales: Aggressive Attitude (AGG-A), Verbal Aggression (AGG-V), and Physical Aggression (AGG-P)—across gender and security levels within Ecuadorian prisons, using the Spanish version of the Personality Assessment Inventory (PAI). This instrument was administered to 215 incarcerated individuals (ages 19–68; M = 34.63; SD = 10.002) across three correctional facilities in Guayaquil (Ecuador). The total sample was stratified into five matched subsamples of 43 individuals each: 1) males in low-security facilities, 2) males in medium-security facilities, 3) males in high-security facilities, 4) males across all security levels combined, and 5) females across all security levels combined. The results indicated that the female subsample scored significantly higher than the combined male subsample on the AGG-A and AGG-V subscales. However, no significant differences were found between the female group and the three male subsamples (by security level) across any of the aggression measures. These findings suggest that while the overall aggression profiles of male and female inmates are broadly similar, notable differences emerge, particularly in attitudinal and verbal hostility, which are more pronounced among women. The implications for institutional security, psychological assessment and intervention, and predicting harm-intended behaviors are discussed. 2026-01-16T08:47:13Z 2026-01-16T08:47:13Z 2025-10 journal article Publisher version: Espinoza-Gárate, P., Quevedo-Blasco, R., López-Vallejo, S. & Burneo-Garcés, C. (2025). Aggression in prison populations by gender and security Level: An analysis using the personality assessment Inventory. Journal of Psychiatric Research, Volume 190, October 2025, Pages 137-144. https://doi.org/10.1016/j.jpsychires.2025.07.010 1879-1379 0022-3956 https://hdl.handle.net/10481/109779 10.1016/j.jpsychires.2025.07.010 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ embargoed access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier