Effectiveness of a peer-supported crisis intervention to reduce the proportion of compulsory admissions in acute psychiatric crisis interventions in an outreach and outpatient setting: study protocol for an exploratory cluster randomised trial combined with qualitative methods


In Germany, as in many other high-income countries, individuals with severe mental health conditions may be admitted to psychiatric hospitals or wards against their will if they are deemed to pose a significant threat to themselves or others, and if this supposed threat cannot be averted in any other way (hereafter referred to as ‘compulsory admissions’). In Germany, the legal basis for compulsory admissions is provided by the respective federal state laws on assistance and safety precautions in cases of mental illness1 as well as by the German Civil Code §1906.2

Compulsory admissions by definition always entail a severe encroachment on fundamental rights.3 Individuals who have been subjected to such processes often describe their experience as stigmatising, discriminating and stressful.4 It is associated with feelings of fear, humiliation and powerlessness.5 A compulsory admission can even result in a post-traumatic stress disorder.6

The number of compulsory admissions in Germany has increased sharply in recent years. Evidence for this can be seen in the number of civil law proceedings in connection with compulsory admissions (2006: 46 557; 2015: 56 646).7 The frequency, duration and type of compulsory admission vary widely between countries, regions and even hospitals, indicating a considerable scope for interventions to decrease the rate and render the process more humane while still complying with legal requirements.8 The practice of compulsory admissions in Germany has been criticised in a report of the United Nations Convention on the Rights of Persons with Disabilities that calls for significant improvements.9

Risk factors for compulsory admission are various psychiatric diagnoses such as organic mental disorders (International Classification of Diseases (ICD)-10 F0), psychotic disorders (ICD-10 F2), especially in connection with addictive disorders and mental retardation (ICD-10 F7).10 Additional risk factors are male gender, migration background, low level of education, unemployment, homelessness, living in an assisted group home or other institutional setting and dependence on transfer payments (social welfare, Pan-European Personal Pension Product).10 Additionally, external factors increasing the probability of compulsory admissions include the structural equipment of facilities such as a lack of staff as well as qualitative equipment features such as inadequate staff training and/or inadequate care.11 Another important factor is the interaction between the patient and the mental healthcare provider, which can have a significant impact on the degree of escalation in critical situations.12

The research project ‘Effectiveness of a peer-supported crisis intervention to reduce the proportion of compulsory admissions (PeerIntervent)’ aims to reduce the proportion of compulsory admissions by implementing peer support in outreach crisis interventions and outpatient acute services. Therefore, peer support workers (PSWs), individuals who have experienced mental health crises themselves, will join crisis intervention teams. The project is being implemented in the city of Bremen. Bremen is a city in the north of Germany with ca. 560 000 inhabitants, and it is also the capital of the federal state of Bremen. In Bremen, the number of annual compulsory admissions has increased by more than 60% within 10 years (876 in 2009, 1426 in 2019).13

Coercive measures are often used in psychiatric care. According to surveys, in retrospect, many service providers consider such measures unavoidable. At the same time, individuals affected by these coercive measures state that alternative measures could have been employed.14

Compulsory admissions are one type of coercive measures. Often individuals affected by compulsory admissions feel discriminated and stigmatised in their interactions with healthcare professionals. They emphasise that a more empathetic approach by healthcare professionals could potentially help them to feel more accepted and taken seriously.15 16 From their perspective, a stronger response to their needs by the providers could have lowered the rate of compulsory admissions.17

In addition, specific training for providers who employ trained PSWs has the potential to facilitate a respectful interaction between patients and staff. In the field of mental health, peer support can offer social and emotional assistance, frequently coupled with instrumental support, that is, mutually offered or provided by persons having a mental health condition to others.18

PSWs, in the context of our trial, are individuals who have themselves experienced mental health crises and/or have been diagnosed with a psychiatric condition. Additionally, they have received structured training for PSWs. As PSWs, they use the expertise gained both through their lived experience and training to accompany and support other people in crises and/or with mental health conditions on equal, non-hierarchical terms.

Patients whose treatment in acute settings had involved peer support reported that they had more confidence in individuals who have experienced mental health crises themselves. They appreciated these contacts as well as the non-medical language of the PSWs and felt that they were really listened to.19 Several studies have shown that peer support in mental health treatment can have a beneficial impact on individuals with severe mental health conditions. For instance, it has been shown that peer support leads to increased self-efficacy and a lower rate of readmissions to acute care.20–23 In addition, peer support can potentially improve recovery,24 25 mental and physical health,24 26 as well as quality of life,24 reduce inpatient admissions20 and increase the voluntary use of clinical, psychosocial and vocational support services.27 There is also evidence that peer support is able to reduce the use of coercive measures.28 As a consequence, on an international level, peer support is recommended in an increasing number of clinical guidelines to prevent coercive measures and improve treatment outcomes.23 29–35

So far, the effectiveness of peer support in the context of mental health conditions has been shown in both acute and non-acute inpatient settings as well as in non-acute outpatient settings.19 21 28 36 However, to our knowledge, the involvement of PSWs in outreach crisis interventions and outpatient acute settings has not yet been studied in Germany. Our trial is intended to close that gap by exploring whether peer support can help prevent or reduce the rate of compulsory admissions in the context of outreach crisis intervention. To our knowledge, this is the first controlled intervention trial that studies the participation of PSWs to reduce the proportion of compulsory admissions.

The main aim of the PeerIntervent project is to improve the care of individuals in an acute mental health crisis and, therefore, reduce the number of compulsory admissions. To achieve this, peer support will be implemented in the existing crisis intervention service (CIS) in the city of Bremen. The CIS in the city of Bremen is responsible for responding to individuals in a mental health crisis. It is part of the Public Health Service in Bremen and is operated by the public network of hospitals ‘Gesundheit Nord’ (Geno).

The following research questions will be investigated:

  1. Does the implementation of peer support in crisis interventions by the CIS help to reduce the proportion of compulsory admissions?

  2. How do individuals with severe mental health conditions perceive the work of the CIS in crisis situations with and without PSWs?

  3. How do PSWs perceive their own role in crisis interventions?

  4. How does the (non-peer) CIS staff perceive the involvement of PSWs in their teams?



This is an exploratory, cluster randomised study. Two of the five mental healthcare regions are assigned as intervention regions, the other three regions serve as controls. The regions are randomised by using the R-function ‘sample’ to randomly select two of the five regions. In those two randomised intervention regions in the city of Bremen (Germany), peer support will be provided in CISs. Furthermore, training will be provided to the police force. The remaining three regions will constitute the control groups in which the CIS will provide care as usual without peer support and the associated police departments do not receive training. The multidisciplinary CIS teams provide outreach crisis interventions and outpatient acute services in acute mental health crises (figure 1).

Figure 1
Figure 1

Flow chart of the cluster randomised trial.

The primary outcome parameter is the proportion of compulsory admissions in all crisis interventions assessed with routine data. In addition, a qualitative process evaluation will be conducted through semistructured interviews with patients and PSWs and focus group discussions with the (non-peer) CIS staff.

The recruitment of participants runs from April 2023 to March 2024.

Study characteristics are described according to the spirit guidelines.37 The study was approved by the Ethics Committee of the University of Bremen (file 2022-09) on 20 June 2022 and was registered at the German Clinical Trials Register (Deutsches Register Klinischer Studien; DRKS) on 4 July 2022 (Registration Number DRKS00029377). For any protocol modification, agreement will be sought beforehand from the ethics committee. It will also be documented in the trial registry. This study protocol is the first version (18 December 2023).

Theory of change

The study was developed using a theory-driven approach for the design, implementation and evaluation of complex interventions, employing a theory of change (ToC). The ToC approach can increase the likelihood that the intervention is ultimately effective, sustainable and scalable.38 The ToC outlines the necessary interventions (eg, peer support, training) along with their underlying rationales or assumptions. Over the course of the study, three ToC workshops take place in which all stakeholders (individuals experiencing mental crises, CIS staff, police, public health and academia) bring in their perspectives. The first workshop aims to establish realistic expectations and consensus among all involved stakeholders regarding the project. The second workshop prepared the intervention. A final workshop will take place after the intervention to incorporate the findings in the ToC.

Patient and public involvement

Patients and other stakeholders are involved at several levels. (1) They are involved in the development of the ToC that guided our study design. (2) We co-operated with the ‘Trialogical advisory board (EmPeeRie NoW)’ of the Department of Psychiatry and Psychotherapy at the University Medical Center Hamburg-Eppendorf. The board comprises individuals with personal experience of mental crises or experience as family members, thus representing a broad range of experiential expertise. The board was consulted for the study’s conceptualisation and the development of study materials (eg, interview guides, consent forms).39 (3) Experts with practical experience in the care of individuals in acute mental health crises are involved through their membership in the coordination committee which meets every three months. Obstacles to intervention implementation and the alignment with the expectations of various stakeholders are highlighted and discussed. The coordination committee consists of representatives from CIS staff, the PWSs, scientists from the project team and representatives from health, social authorities and the police force.

Setting and team structure

The state social psychiatric counselling service in Bremen, which is responsible for dealing with mental health crises, is divided into five service regions: North, East, South, West and Central. Each region has a social psychiatric counselling centre that offers the CIS. The CIS operates regionally on weekdays between 08:30 am and 03:00 pm during the day. On weekdays after 03:00 pm until 11:00 pm and on weekends between 08:30 am and 05:00 pm, a centralised CIS is being provided. Outside of these hours, psychiatric emergencies are exclusively handled by the police. Therefore, the cluster randomised quantitative evaluation is limited to the period from 08:30 am and 03:00 pm on weekdays. Accordingly, the PSWs will be employed during this period.

There are two ways the CIS can be contacted: first, the CIS is usually being contacted by phone, either by the patient himself/herself, by the police (if they were contacted first), or by a third party (relatives, citizens). The CIS assesses the urgency of the crisis and, if necessary, a team of at least two CIS staff members visits the patient. Additionally, CIS will request police support if it deems necessary to forcefully access the patient’s home to rule out the patient’s self-endangerment or endangerment of others or if immediate endangerment of service workers is to be expected, as of previous experience. In some cases, the police will be on site first hence requesting support of CIS. Acute crisis intervention includes, as one of the CIS’s tasks, the assessment of the danger of the patient to himself/herself and others, and if this is not ensured, the CIS can initiate compulsory admission in accordance with German law (PsychKG §§18-19).40

Second, the CIS is offering open consultation hours, that is, individuals can make visits without appointment. A compulsory admission may occur during a consultation, although this rarely happens.

Intervention (PSWs and training of the police force)

The intervention consists of two elements: (1) employing PSWs in addition to the regular staff in the CIS to participate in crisis interventions and other aspects of the CIS’s daily care routine and offer support to patients after the crisis and (2) preparing the police force for patients in mental health crisis interventions.

Intervention element 1: peer support

To be eligible to work on the project, PSWs need to have personal experience with mental health crises and have completed the Experienced-Involvement (EX-IN) training curriculum and certification by the EX-IN association. The EX-IN curriculum includes 12 modules (250 hours) that cover topics such as recovery, trialogue and crisis intervention, among others. Participants also have supervision sessions and self-reflection exercises to identify their competencies and qualifications. Additionally, the participants must complete two internships during the training, each for 120 hours.41

Moreover, the PSWs employed should ideally have already gained initial experience in working as PSWs in a psychiatry. Before the start of the intervention, the CIS teams and the new PSWs will receive training from the project team to prepare them for concrete deployment in the CIS and in crisis situations. They will be prepared for challenging situations in the form of role plays, and self-care skills are taught while the PSWs are being supported in recognising their own individual stress triggers.

The main element of the intervention is the participation of PSWs in crisis interventions. Before the intervention phase starts, there will be a three-month pilot phase in which the PSWs get to know the work of the CIS, develop their own roles and gain initial experience of working in this setting. The aim of the pilot phase is to further elaborate the role and associated tasks of the PSWs when participating in crisis interventions. There will be enough time for reflection and exchange to identify possible problems and modify the procedures if necessary.

During the pilot and intervention phases, the PSWs will receive supervision and team supervision, where they can discuss challenging situations together and/or with a psychologically trained supervisor from the project team. In each CIS, two PSWs are being recruited, and in addition, one designated contact person with an EX-IN trainer certification will be named, whom they can approach if necessary.

Besides participating in crisis interventions, PSWs will offer patients further support services for stabilisation or transition after crisis interventions.

Intervention element 2: training of the police force

The training of the police force offers an opportunity to exchange experiences with individuals with a severe mental health condition and to raise awareness of mental crises. For the police force’s training, we will use a concept developed by the initiative ‘Crazy is human Hamburg’, which has already been successfully implemented and evaluated for the training of police officers in the city of Hamburg (Germany).42 In the two intervention regions, workshops will be first offered to staff at the management level (approximately 20 participants per region; each workshop will last for about six hours) and thereafter to all police staff. The workshops will be led by at least two persons, a mental health professional and a person who has experienced mental health crises himself/herself. In short exercises, the perspective of individuals with severe mental health conditions during a police operation is being taken, for example, on hearing voices. The duration is about four to six hours.

Control: care as usual

In the three regions which have been randomised as control groups, care will take place as usual. No PSWs will be deployed, and the police force will not receive any specific training.

Inclusion criteria

Data on CIS contacts with and without compulsory admissions will be collected by extracting routine data. Only data of individuals over 18 years of age who had face-to-face contact with the CIS and for whom the contact was documented as a mental health crisis by the CIS team will be analysed. Among these, compulsory admissions are defined as those where involuntary placements in a psychiatric hospital take place (PsychKG §§18, 19 and BGB 1906).2 40


Quantitative evaluation

The primary outcome parameter will be the proportion of all compulsory admissions in the intervention regions compared with the control regions during the intervention period (12 months) and in relation to 12 months before the start of the pilot phase (baseline survey). Additional data transferred to the study group and evaluated will be age group (in ten-year age intervals), gender, region and whether a PSW was involved in the intervention or not. As the participants are not in the position to give an informed consent, we have to operate with data that ensures complete participant anonymity. This is achieved by analysing data that has been highly aggregated. In our case, we will receive aggregated data on the primary outcome parameter and additional data on the age group (in ten-year age intervals), gender, region and whether a PSW was involved in the intervention or not.

Qualitative process evaluation

Interviews with patients

Qualitative individual interviews will be conducted about three months after the crisis event with 15 patients from the intervention group and 15 patients from the control group, respectively. The interviews focus on the perspective of the patients on the situation around the crisis and on the subsequent phase with and without peer support. Interview guidelines have been developed for each group based on previously defined categories: experiences with crises, respectful interaction, the meaningfulness of peer support intervention and self-image.

Interviews with PSWs

Qualitative individual interviews will be conducted with the PSWs for an in-depth understanding of their experiences with work in crisis teams, especially in the context of crisis interventions. Interviews will be conducted at the end of the pilot phase and at the end of the intervention phase. The interview guideline comprises the categories: everyday work, experiences with crisis interventions, adjusting to the new role, team dynamics and perceived meaningfulness of peer support intervention.

Focus group discussions with (non-peer) CIS staff

A guideline-based focus group discussion with (non-peer) CIS staff will be conducted in each of the two intervention regions at the end of the intervention phase for an in-depth understanding of how the (non-peer) CIS staff perceived the cooperation with the PSWs. The focus group guideline comprises the categories: everyday work, experiences with crisis interventions, team dynamics, collaboration with PSW and Police.

All interviews and focus groups will be conducted by a staff member of the Department of Health Service Research at the Institute for Public Health and Nursing Sciences of the University of Bremen and will take place either in the presence or remotely via video conference. The interview guidelines will be piloted with members from the respective target groups before the start of the intervention phase and adapted if necessary.

Recruitment and consent

Quantitative evaluation

All individuals aged 18 and older who experience an acute mental health crisis during the operating hours of the regional CIS in all five service regions of the city of Bremen will be included in the study. Prior informed consent to participate in the study cannot be given by individuals during an acute mental health crisis. In the case of this study, informed consent is not required as only routine data for providing healthcare is being used. Interventions of the CIS are documented afterwards in the hospital information system by staff members. Crisis interventions and compulsory admissions are directly categorised as such in the documentation system; furthermore, staff members can document details on the crisis intervention using a free text. Information about the place of intervention, the involvement of police, and the professions and names of the participating staff members is inferred from the free text, administering dual control principle. Data will be transferred from the healthcare provider GENO to the research team anonymously.

Qualitative process evaluation

15 patients from each group, intervention and control, will be drawn on a random basis and contacted by the CIS three months after crisis intervention. If a patient declines to participate, an additional patient will be randomly selected until the target number is achieved. Patients will be contacted by the research team only after informed consent has been obtained.

All PSWs and CIS staff working on the project will be contacted and included in the study if they give written informed consent. The anonymity of the individual participants is difficult to guarantee in this small sample and the participants’ consent to the publication of the selected text passages from the interviews and focus groups is therefore obtained prior to publication.

Participation in the interviews is voluntary and can be withdrawn at any time. Additionally, participants are provided with information on whom to contact should they require professional assistance following the interview.


Data collection and management

According to existing standards, the CIS staff documents each crisis intervention afterwards using the software SAP. Compulsory admissions are documented accordingly by the staff of the mental ward. GENO handles the data according to its standard data protection guidelines, which are unaffected by the research project. GENO provides the anonymised datasets with randomly generated numbers for age groups (in ten-year intervals), gender, the CIS region where the placement took place, compulsory admission yes/no and the presence of PSW yes/no.

Data monitoring and quality assurance

A plausibility check of the data relevant to the study takes place at GENO. No biomaterials are being extracted or stored. The statistical evaluation is carried out by the Competence Center for Clinical Trials Bremen at the University of Bremen.

A coordination committee shall be established to facilitate the project, consisting of the participating institutions as well as representatives from CIS staff, employed peers and representatives from health and social authorities. This committee will convene at three-month intervals and assume responsibility for supervising the implementation of the intervention while also conducting assessments of potential incidental findings and adverse events.

Additionally, every three months, an exchange will take place between the study investigators and representatives from the CIS, where an assessment will be conducted to determine if an increase in adverse events is observed. In addition to the mentioned categories, active inquiries will be made regarding observations of unforeseen adverse events that were not predefined. Based on the frequency and intensity of such events, decisions will be made regarding modifications, partial or complete termination of the study.

Primary outcome measures

The primary outcome parameter (proportion of all compulsory admissions to crisis interventions) will be collected in the intervention and control regions during the intervention period (12 months) and during a period of 12 months before the start of the pilot phase (as a baseline survey).

Statistical analysis

The collected data from the cluster RCT will undergo quantitative analysis. Initially, a descriptive comparison of the regions will be conducted. This comparison will focus on the proportion of compulsory admissions in all crisis interventions during the baseline year and the intervention year. Additionally, changes over time will be examined. The regions will also be compared descriptively concerning essential characteristics (distribution of gender and age groups) during both the baseline and the intervention years. In addition, the effect of the intervention on the probability of compulsory admission is examined through a generalised estimating equation (GEE) for the proportion of compulsory admissions in the intervention year. This is done by including baseline characteristics of the region (proportion of compulsory admissions) and characteristics of the respective case (age group and gender) as well as a correction for the small cluster number.43

Qualitative analysis

Qualitative interviews and focus groups will be audio-taped and transcribed. The evaluation is carried out following the qualitative content analysis according to Kuckartz44 using the MAXQDA software.

Ethics and dissemination

This study was approved by the Ethics Committee of the University of Bremen (file 2022009) on 20 June 2022. We confirm that the ethics committee of the University of Bremen approved the consent procedure for patients undergoing a mental health crisis. All research will be carried out in accordance with the Declaration of Helsinki. The results of this clinical trial will be presented at scientific conferences and submitted to both peer-reviewed and non-peer-reviewed journals. Furthermore, the findings will also be prepared, presented and published for a non-academic audience from a practical perspective. Additionally, the results will be communicated by the Ministry of Health, women and consumer protection, Bremen and the department of health, Bremen through the Health Ministers Conference and the Federal Association of Local Health Authorities.

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