Over recent years, in Italy, the treatment of mentally ill offenders has undergone profound changes following successive legislative interventions, culminating in Law no. 81/2014, which closed all high-security psychiatric hospitals (OPG) and established a community-based forensic care model managed exclusively by the National Health Service. This model, centred on REMS and territorial mental health services, is unique in the Western context and emphasises rehabilitation, recovery, and time-limited custodial measures.

In California, forensic treatment is regulated by the California Penal Code and delivered mainly within high-security state hospitals coordinated by the Department of State Hospitals (DSH), with long average lengths of stay and strong standardisation of security procedures. The two systems therefore differ markedly in structure, duration of stay, and balance between security and rehabilitative goals, raising questions about their respective effectiveness in terms of clinical outcomes, functional recovery, and violent recidivism.

This multicentre, prospective cohort study compares Italian forensic patients (Group I) and Californian forensic patients (Group C), enrolled at first entry into forensic care and followed longitudinally for three years with assessments at T0, T1, T2, and T3 using harmonised tools (BPRS 4.0, WHODAS 2.0, HCR-20 V3, SAPROF, DUNDRUM Toolkit, MOAS) and a common data collection form. Primary aims include a detailed epidemiological characterisation of the Italian forensic population and a systematic comparison of outcomes between the Italian and Californian models with respect to violent recidivism, length of stay in forensic settings, clinical and functional improvement, and recovery indicators.

Comparative analyses focus on subgroups of participants with psychotic disorders and mental disorders directly related to the index offence, in order to examine differences in outcomes attributable to systemic and organisational features of the two forensic treatment models rather than to diagnostic or criminological heterogeneity.

This longitudinal, multicentre, non-randomized cohort study compares outcomes for mentally ill offenders entering Italian and Californian forensic care systems for the first time. The Italian cohort (Group I) comprises individuals subject to custodial security measures in REMS and to non-custodial security measures (for example supervised liberty and dedicated community residential facilities), managed by Departments of Mental Health in residential, semi-residential, and community-based settings. The Californian cohort (Group C) comprises patients admitted to secure state hospitals or community forensic facilities under incompetency to stand trial (IST) or not guilty by reason of insanity (NGRI) provisions of the California Penal Code.

The observation period extends over three years from baseline (T0), with follow-up assessments at 12 months (T1), 24 months (T2), and 36 months (T3), or at discharge from the forensic system if discharge occurs earlier. At T0, data collection includes a structured form covering sociodemographic characteristics, clinical history, substance use, previous psychiatric admissions, self-harm and hetero-aggressive behaviour, current and past pharmacological treatment, and judicial information such as type of offence, duration and type of security measure, previous convictions, and prior detention periods. Baseline assessment also includes BPRS 4.0 for psychiatric symptom severity, WHODAS 2.0 for global functioning, HCR-20 V3 for violence risk, SAPROF for protective factors, and DUNDRUM-1, -3, and -4 for therapeutic security level, treatment programme completion, and recovery status, respectively.

During follow-up, the same battery (BPRS 4.0, WHODAS 2.0, HCR-20 V3, SAPROF, DUNDRUM-1/3/4) is administered at T1, T2, and T3, and clinicians record sentinel events, including new offences, compulsory psychiatric hospitalisations, seclusion or restraint episodes, suicide attempts, suicides, and unauthorised absences or escapes, with violent incidents coded using the Modified Overt Aggression Scale (MOAS). Time windows for each follow-up assessment are restricted (maximum approximately 2 weeks) and are applied uniformly across participating sites to minimise temporal bias in outcome measurement. At the end of the three-year observation period, or at discharge, a Clinical Global Impression - Change (CGI-C) interview is conducted with treating health professionals to capture their structured judgement regarding the quality and effectiveness of the overall treatment pathway.

Inclusion criteria encompass adult offenders (≥18 years) with partial or total mental infirmity placed under forensic measures in Italy or admitted to forensic care in California, whereas exclusion criteria include age under 18 years, severe cognitive impairment (for example Mini-Mental State Examination score <18) preventing valid assessment, inability to provide informed consent in the absence of a legal guardian, and acute medical conditions incompatible with study procedures. Target sample size is approximately 300 participants per group, which provides adequate statistical power to detect clinically meaningful differences between systems while allowing for attrition during follow-up, although the study remains informative even with lower enrolment in line with observational research standards.

Primary outcomes include violent recidivism, length of stay in forensic settings, and changes in clinical and functional status, while secondary outcomes focus on changes in structured risk and protective factors, treatment adherence, therapeutic progress, and recovery indicators. Harmonised instruments and procedures across Italian and Californian sites allow direct comparison of trajectories, with particular attention to subgroups with psychotic disorders and mental disorders related to the index offence, in order to disentangle the impact of system-level organisational and legal features from individual clinical profiles.

Inclusion Criteria:

Group I - Italy:

All subjects subject to custodial security measures (e.g., REMS) or non-custodial security measures (e.g., supervised liberty, placement in dedicated forensic community residential facilities - CRAP), regardless of clinical diagnosis or type of offence committed

Both definitive and provisional security measures are included

Management contexts include residential, semi-residential, and community-based settings

Age ≥ 18 years

Group C - California:

Patients admitted to secure hospitals or community forensic facilities for incompetency to stand trial (IST) or not guilty by reason of insanity (NGRI), pursuant to the California Penal Code

Exclusion Criteria:

Age under 18 years

MMSE score below 18 (severe cognitive impairment preventing administration of study instruments)

Inability to provide written informed consent and absence of a legal guardian or Support Administrator available to provide substitute consent

Acute medical conditions preventing the administration of the evaluation instruments specified in the research protocol

The study population consists of mentally ill offenders, with total or partial mental infirmity, entering Italian forensic care settings (Group I: REMS or non-custodial forensic settings) or Californian hospital forensic facilities (Group C) for the first time during the enrolment period. The Italian sample will be recruited through the national network of Departments of Mental Health (DSM) and forensic structures (REMS and community forensic services) participating in the study, coordinated through the Regional Single Contact Points (P.U.R.) established under the 2022 Unified Conference Agreement no. 188/CU. The Californian sample will be recruited through the Department of State Hospitals (DSH) network under the coordination of Prof. Katherine Warburton.

I have not decided yet