Table 1.

Description of included studies

Reference; program title; Country	Program description (setting, modality, lived experience etc.)	Study aim and methodology	Sample characteristics (where relevant)	Key findings (where relevant)
References: [29, 30] Title: Selbstmordforum.de (Translation: suicideforum.de) Country: Germany	Setting: Online messaging boards (forums); Modality: Group support; Target group: Users of online suicide forum Lived experience: 88% of study participants reported suicide ideation; 54% of participants had made at least one suicide attempt in their life. 28% had suicidal thoughts for the first time 1–3 years ago; 34% had suicidal thoughts more than 5 years ago for the first time; 12% never had suicidal thoughts.	Aim: Investigate whether the use of online suicide message boards is harmful or beneficial to people with suicidality. Methodology: Quantitative cross-sectional study; Convenience sample; online questionnaire of people using the online suicide message board “selbstmordforum.de”; Analysis of users’ socio-demographic characteristics, their motivations for participation, what content they shared, and what effect participation in online suicide messaging boards had on participants	164 participants; 50% male, 50% female; sample biased to young adults with 59% under 21 years and 88% under 30 years; 80% single; 67% students or in higher education settings	Online suicide forums do show signs of support and constructive help through conversations with other people with lived experience. Decrease in intensity of suicidal thoughts during the respondents’ participation in the suicide forum; 31% of participants say the decrease is due to their participation. Participation does not seem to increase help-seeking. Only 22% of respondents said they were more motivated to seek help. Motivation to use the forum was feeling understood and receiving comforting reactions.
Reference: [31] Title: Suicide messaging boards Country: Germany/Austria	Setting: Online messaging boards (forums); Modality: Group support; Target group: Users of online suicide messaging boards Lived experience: Suicidality of the online user was coded according to the content in the comments on the messaging board.	Aim: Identifying communication patterns that can be used to improve suicidality of participants on online suicide message boards. Methodology: Qualitative study; Secondary data analysis of a random selection of threads from 7 pre-identified suicide message boards (online forum); Thematic analysis of threads	401 threads from anti-suicide boards, 382 threads from neutral boards; 399 threads from pro-suicide boards	Constructive advice, active listening, collaborative problem solving, expression of sympathy, debunking the suicide myths, and provision of alternatives to suicide and positive stories of lived experience help to improve a participant’s suicidality.
Reference: [35] Program: Montgomery County Emergency Service—Peer specialist support Country: USA	Setting: Hospital, patient care; Modality: Mixed mode, including one-on-one peer support; two part-time peer specialists provide services to in-patients, families and community members including support groups, one-on-one counseling, training and capacity building in the community. Target group: Patients of a psychiatric hospital and people in crisis support Lived experience: Peer specialists have past experience of suicide and received peer support and recovery training.	Aim: Description of suicide prevention service within a hospital—in-patient care	N/A.	N/A.
Reference: [34] Program: Health Intervention Training—Mutual Aid Network (HIT-MAN) Country: China	Setting: Schools; Modality: Peer group support based on a social network approach; Objectives are to encourage students to support and, in some cases, refer their friends who have been thinking about suicide or showing very poor self-esteem and signs of depression to a trusted adult (who will also be part of the HIT-MAN training network). Target group: School students (adolescents), teachers and school communities Lived experience: Students in peer groups have lived experience of mental health problems which are seen as early warning signs of the trajectory to suicide.	Aim: Description of a suicide prevention program that helps students to identify problems of extreme stress, anxiety and suicidal feelings in their peers, including training and peer support groups.	N/A.	N/A.
Reference: [32] Program: Peers for Valued Living (PREVAIL) Country: USA	Setting: Inpatient psychiatric unit and post discharge care Modality: One-on-one peer support; Peer specialists first meet patients in inpatient unit and then provide support for 12 weeks after discharge (max 16 meetings); flexible meeting arrangements (frequency and duration); Target group: Patients admitted to an inpatient psychiatry due to suicidality Lived experience: Peer specialists had lived experience of serious suicidal thoughts or behaviour.	Aim: Development and pilot testing of a peer specialist intervention to reduce suicide risk, Methodology: Pilot randomised controlled trial; randomisation of participants to normal care and PREVAIL peer support intervention; Semi-structured interviews to capture participant experiences and feedback	70 adult patients (age 18 or older) from two inpatient psychiatric units; patients had to have history of suicidal ideation or attempt; patients were excluded from participation if they showed unstable psychosis, cognitive impairment, severe personality disorder, invasive therapy. 34 were allocated to the peer support arm and 36 received usual care.	Feasibility and acceptability for the program was assessed by collecting quantitative and qualitative data on peer specialist performance and training. No data was provided on the efficacy of the program to reduce suicidality due to lack of power in the trial.
Reference: [28] Program: Alternatives to Suicide through the Western Mass Recovery Learning Community (RLC) Country: USA	Setting: Community led intervention; Modality: Peer support group for people who experience suicidality; underpinned by the key principles of Validation + Curiosity + Vulnerability + Community; It creates conditions that support recovery at both the individual and community level through trauma-sensitive peer supports and the development of a regional network. Target group: People who experience suicidality (not bereavement) Lived experience: Peer support groups are open to anyone with lived experience of suicidal thoughts or attempts; Leaders who struggled with thoughts of suicide or suicide attempts and who wanted to support others.	Aim: Description of the Alternative to Suicide (ATS) peer support program, an innovative peer-led suicide prevention program from the Western Massachusetts Recovery Learning Community (RLC). Methodology: Internal feedback survey with attendees of support groups.	not available	Early findings from an internal feedback survey with attendees of the support groups: attendees felt most strongly that attending the groups was helpful because they could talk freely; attending had improved at least one area in attendees’ lives; increased sense of community and increased understanding on why suicidal thoughts may come up were areas with greatest improvement.
References: [33, 36, 37] Program: The Way Back Support Service—Peer CARE Companion Program Country: Australia	Setting: Community-based intervention; Modality: One-on-one support; Target group: People with lived experience of suicide (suicidal crisis or after a suicide attempt) Lived experience: Peer support is customised depending on whether peers are to be supporting people at risk. Lived experience of the peer care companion will be matched with the person in need.	Aim: Description of the Peer CARE Companion program which provides peer support to people with lived experience of suicide or bereaved by suicide.	N/A.	N/A.