Experimental Design
Recruitment and informed consent
The model trial will be carried out during the 34-month study period (enrollment window) between December 4, 2023 and September 30, 2026. Study participants will be recruited in 11 pretrial detention facilities in the cantons of Zurich and Bern. All seven pretrial detention facilities in the Canton of Zurich (Prison Dielsdorf, Prison Horgen, Prison Limmattal, Prison Pfäffikon, Prison Winterthur, Prison Zürich, Prison Zürich West) and all four pretrial detention facilities in the Canton of Bern (Prison Bern, Prison Biel, Prison Burgdorf, Prison Thun) will participate in the model trial. Based on historical data, we expect around 5’100 people to enter pretrial detention in the cantons of Zurich and Bern during the 34-month duration of the model trial. See supporting document “Eligibility criteria” for a description of the eligibility criteria for the two interventions.
During the informed consent procedure, guards will explain to each participant the nature of the study, its purpose, the procedures involved, the expected duration, the potential risks and benefits and any discomfort it may entail. Each participant will be informed that the participation in the study is voluntary and that he or she may withdraw from the study at any time, and that non-participation or withdrawal of consent will not have consequences for how they are treated during pretrial detention, nor will it be considered in any legal procedure. To ensure consistent quality, a video is available in all 14 study languages, explaining the above mentioned key features in an accessible way.
Subjects eligible for the PRISMA intervention or for both interventions will be asked to consent to the following (consent form “A”):
1. Being randomized into a PRISMA treatment or a control group
2. Voluntarily participating in the PRISMA intervention if being randomized into the treatment group
3. Being invited to multiple survey assessments
4. Sharing their prison internal medical data from prison health services and doctors
5. Linking the additionally collected survey data and the shared prison internal medical data with the administrative data (i.e., prison internal non-medical data and external administrative register data) collected by administrative organizations (prisons, Swiss Federal Statistical Office, Central Compensation Office)
In addition, subjects can give consent (in consent form “A”) on whether they are willing (or not) to voluntarily disclose their external health insurance provider data.
Subjects eligible for only the proactive social service intervention will be asked to consent to the following (consent form “B”):
1. Being invited to multiple survey assessments
2. Sharing their prison internal medical data from prison health services and doctors
3. Linking the additionally collected survey data and the shared prison internal medical data with the administrative data (i.e., prison internal non-medical data and external administrative register data) collected by administrative organizations (prisons, Swiss Federal Statistical Office, Central Compensation Office)
In addition, subjects can give consent (in consent form “B”) on whether they are willing (or not) to voluntarily disclose their external health insurance provider data.
Subjects not eligible for neither the PRISMA intervention nor the extended social service intervention are not randomized and only serve as an observational group. They are asked to consent to the following (consent form “C”):
1. Sharing their prison internal medical data from prison health services and doctors
2. Linking the shared prison internal medical data with the prison internal non-medical data
Randomization samples and treatment assignment
Depending on whether participants fulfill eligibility and provide consent for the PRISMA intervention, the social service intervention, or both, they will be allocated into one of the following three randomization samples:
Randomization sample A: Subjects who are only eligible for PRISMA but not for proactive social services and who consent are randomized into one of the following two conditions with equal probability:
1. PRISMA: participants in this group are offered the psychological intervention PRISMA.
2. REGULAR PRETRIAL: participants in this group experience the same system and conditions that they would have experienced if the RCT did not exist. In particular, they will not be offered PRISMA, but they can still access medical support through the jails’ health services.
Randomization sample B: Subjects who are only eligible for proactive social services but not for PRISMA are randomized into one of the following two conditions with equal probability:
1. SOCIAL: participants in this are offered extended support from social services. If during the intake interview the social services identify the need for (immediate) measures to preserve external resources, these measures will be discussed with the inmate. For the social services to take action, the inmate (and the prosecution office) must consent to every intended measure.
2. REGULAR PRETRIAL: participants in this group experience the same system and conditions that they would have experienced if the RCT did not exist. In particular, they will not be offered proactive social services, but they can still access social services upon request.
Randomization sample C: Subjects who are eligible for both interventions and who consent are randomized into one of the following four conditions with equal probability:
1. PRISMA: participants in this group are offered the psychological intervention PRISMA.
2. SOCIAL: participants in this are offered extended support from social services. If during the intake interview the social services identify the need for (immediate) measures to preserve external resources, these measures will be discussed with the inmate. For the social services to take action, the inmate (and the prosecution office) must consent to every intended measure.
3. PRISMA & SOCIAL: participants in this group are offered both the psychological intervention PRISMA and the extended support from social services.
4. REGULAR PRETRIAL: participants in this group experience the same system and conditions that they would have experienced if the RCT did not exist. In particular, they will not be offered PRISMA or extended social services, but they can still access social services upon request as well as medical support through the jails’ health services.
Subjects who are only eligible for the proactive social service intervention (randomization sample B) will be randomized into the group SOCIAL or the group REGULAR PRETRIAL irrespective of consenting to consent form “B” or not. For subjects not consenting to consent form “B”, The effects of the proactive social service intervention can still be evaluated using only prison internal non-medical data and external non-medical administrative register data. Federal regulation permits the use of this pseudonymized data without consent.
Subjects who are eligible for both interventions (randomization sample C), but do not provide consent using consent form “A” will be transferred from randomization sample C to randomization sample B. They will thus be treated as if they were not eligible for PRISMA, and the effects will be evaluated using only prison internal non-medical data and external non-medical administrative register data. The reason for this transfer from randomization sample C into randomization sample B is the following: Without consent, we cannot evaluate survey data nor any medical data, which both are essential for evaluating the effects of the PRISMA intervention. However, without consent, we can still evaluate prison internal non-medical data and external non-medical administrative register data.
Outcome Data Collection
The research team will collect outcome data from administrative data sources and surveys (see supporting documents “Survey questions and schedule” and “Administrative data source”. The first (baseline) survey will be administered before randomization. Subsequently, surveys will occur according to a pre-specified schedule (at the day of exit from pre-trial detention, 3 weeks after intake, 10 weeks after intake, 6 months after intake, and 1 year after intake).