Comparison of the Italian and U.S. Forensic Models for Dual-diagnosis Offenders: a 3-year Longitudinal Study

This study aims to compare the Italian and U.S. forensic models in the treatment of offenders with dual diagnosis through a three-year longitudinal design. In Italy, the closure of Judicial Psychiatric Hospitals following Law 81/2014 led to the establishment of a community-based forensic system centered on REMS (Residences for the Execution of Security Measures), integrated within the National Health Service. This model seeks to limit institutionalization and promote rehabilitative pathways in community settings. However, it continues to face challenges related to limited bed availability, waiting lists, and the complex management of social dangerousness. In contrast, the U.S. system, particularly in California, is characterized by high-security forensic psychiatric hospitals with large capacities, but also presents issues such as prolonged hospitalizations, an aging patient population, and a high prevalence of substance use disorders.

Dual diagnosis, defined as the co-occurrence of psychiatric disorders and substance use disorders, is highly prevalent in forensic populations and is associated with increased clinical complexity, higher risk of recidivism, and poorer treatment outcomes. Neurobiological and psychological mechanisms underlying addiction-including dysfunctions in the dopaminergic reward system, craving processes, and impairments in executive functioning-contribute to reduced behavioral control and increased impulsivity. Theoretical models such as the self-medication hypothesis and multifactorial frameworks suggest that substance use may both exacerbate psychiatric symptoms and represent an attempt to regulate them.

Given these complexities, integrated treatment approaches that combine psychiatric care and addiction interventions are essential, particularly in forensic settings. The present study includes offenders with mental illness in forensic care systems in Italy and California, encompassing both custodial and non-custodial settings. Participants will be followed over a three-year period, with assessments conducted at 12, 24, and 36 months. The methodology involves the use of standardized instruments to evaluate psychopathological severity, global functioning, risk of violent recidivism, protective factors, treatment adherence, impulsivity, and substance use. Data on clinical outcomes, antisocial behaviors, and discharge conditions will also be collected.

The primary objectives of the study are to describe and compare the clinical, demographic, and criminological profiles of forensic populations with dual diagnosis; to examine treatment pathways and outcomes; to identify indicators of treatment effectiveness; and to evaluate both risk and protective prognostic factors, as well as their predictive value for recidivism and clinical trajectories.

The expected impact of the study lies in improving the understanding of differences between community-based and hospital-based forensic models, with the goal of identifying integrated strategies capable of enhancing rehabilitation, reducing recidivism, and improving long-term outcomes. Findings may contribute to the development of more effective and individualized treatment approaches, as well as inform health and judicial policies aimed at better integrating clinical care and risk management in dual diagnosis forensic populations.