Table 6.

Review Question 1 findings

	Intervention type:
	Peer Education	Peer support	Listeners	Prison hospice volunteers	Peer mentoring	Health trainers	Other
Knowledge	Ten studies [66,68,69,84,88,90,93,97,98]	Two qualitative studies showed reported increases in knowledge [58,80]. In one of these studies, a number of respondents noted that knowledge acquired from the training was applicable to improving relationships with their children, partners and others in the community [58].	Enhanced skills as a result of being a peer deliverer, like listening and communication, was mentioned by two studies [56,61] and there was indication of prisoners feeling able to put these skills into practice on release from the institution [61].			Two qualitative studies showed increased knowledge on a variety of topics, including: drugs, sexual health, nutrition, alcohol and mental health issues [54].
	Statistically significantly higher proportion of correct answers to 22/ 43 questions asked in peer education vs control group. RR 0.43 (95% CI: 0.33, 0.56, 1 study n = 949) to 3.06 (95% CI: 1.91, 4.91, 1 study, n = 200).					Improvements were seen in the mean knowledge scores in all areas in one study [54], but it was not possible to ascertain whether these improvements were statistically significant.
	Knowledge scores: mean difference 0.46 (95% CI: 0.36, 0.56, 2 studies, n = 2494, I2 = 94%).					Both health trainers and Health Trainer tutors reported that Health Trainers had developed effective communication and listening skills as well as fostering attributes essential for team working and future employment after release from prison [54].
	Other evidence: peer educators improved their own knowledge [55,68,76]. and [69] information was diffused to those outside the prison, such as family members and children.
	In the study on literacy [88], > 90% of learners agreed that their reading and communication skills had improved.
Intentions	Four studies [66,69,84,93]		In one study [37] 61% of those surveyed said they could talk to a Listener about anything that was worrying them. 74% had no problems contacting a Listener when they had requested help.
	One RCT [84] reported improvements in: interest in taking HIV test for the first time (RR 1.49, 95% CI: 1.12, 1.97);		57% of users thought they would seek the help of a Listener if they faced a similar problem in the future.
	interest in taking HIV test now (RR 1.82, 95% CI: 1.33, 2.49); condom use intention (RR 1.15, 95% C I: 1.08, 1.22);
	intention to never use condoms (RR 0.59, 95% CI: 0.48, 0.72).
	No improvement in intention to use bleach with drug injecting equipment (RR 1.06, 95% CI: 0.97, 1.16).
	No improvement [67] in intention to take a HIV test (RR 1.24, 95 CI: 0.75, 2.05) and a negative effect on peer educators’ intentions (RR 0.62, 95% CI: 0.41, 0.95).
	A study in South Africa [69] did not show any evidence of a commitment to change their behaviours, X2(10, N = 69) = 10.934, p = .36.
Attitudes/ Beliefs	Four studies [68,69,97,98]	One study [91] showed that a drug treatment intervention that included the support of trained prison counsellors caused changes in prisoners’ reported attitudes to drugs and alcohol. This translated to a self-reported reduction in drug and alcohol use. The one-to-one sessions with trained peer counsellors was regarded as the most “helpful aspect” of the recovery process.				Attitudinal change, often as a result of increased knowledge, was seen primarily in the area of smoking and diet [54,70]..
	No changes in one study [68]; in another [97], improvements seen in agreement with all three statements:					In one study [54], more than 50% of health trainers stated that their attitude had changed in the areas of: healthy eating/ diet; sexual health issues; smoking cessation; exercise; mental health issues. 75% of HTs stated that they would like to get a job as a HT when they are released from prison
	“HIV positive inmates should be separated” (RR 2.55, 95% CI: 1.94, 3.33);
	“I feel safe in the same wing as an inmate who is HIV positive” (RR 0.74, 95% CI: 0.68, 0.84);
	“I know enough to protect myself from catching HIV/AIDS” (RR 0.54, 95% C: 0.50, 0.59).
Behaviour	Eleven studies [21,25,27,60,63,66,68,69,87,89,90,98]		In one study [92], 64% of 22 prisoners claimed that friends and family had noticed a difference in their demeanour, finding them more relaxed, responsible, optimistic, able to speak more and more able to listen. 73% agreed that their new responsibilities would allow them to ‘adjust better’ on release, and 55% agreed that the ‘prison authorities’ appreciated their work. 77% said there was a difference in how immediate staff interacted with them: being trusted more, staff talking more to them, staff being grateful for the work they do. 86% said that fellow prisoners behaved differently towards them.		In one study [83] At 3 months, 38/44 participants (86%) were receiving outpatient psychiatric services and 40/44 (91%) successfully managing their medications.	Health trainers reported eating more fruit and vegetables and one health trainer had given up smoking [54,70]	Peer training: One study [71] reported a statistically significantly reduced rate of confrontation post-intervention at 0.432 (CI: 0.319, 0.583, p < 0.0005).
	Positive effects seen:				At 6 months, 36/44 participants (82%) were medication compliant, and 35/44 (80%) demonstrated symptom reduction. 12/44 (27%) had not maintained sobriety at 6 month time point. 17/22 (77%) participants released for at least 12 months had not been rearrested. 16/22 participants who had been released for at least 12 months (73%) were abstinent in use of alcohol or illegal drugs or misuse of prescription drugs.
	Not using a condom at first intercourse after release from prison (RR 0.73, 95% CI: 0.61, 0.88, 2 studies, n = 400);
	injecting drugs after release from prison (RR 0.66, 95% CI: 0.53, 0.82, 2 studies, n = 400);
	injected in past 4 weeks (RR 0.11, 95% CI: 0.01, 0.85, 1 study, n = 241);
	sharing injection equipment after release from prison (RR 0.33, 95% CI: 0.20, 0.54, 2 studies, n = 400);
	peer educators never having had an HIV test (RR 0.31, 95% CI: 0.12, 0.78, 1 study, n = 847).
	In one Russian study [27] the prevalence of tattooing in prison significantly decreased (42% vs 19%, p = 0.03) and of those who were tattooed the proportion using a new needle increased from 23% to 50%.
	Where behaviour was measured on a scale [60,69,98], positive effects were seen in all three studies.
	HIV tests in prison [87] was associated with having attended a HIV prevention programme in prison (OR = 2.81, 95% CI: 1.09, 7.24).
	Chlamydia screening in the under-25 s rose from 13 to 83 in a 6 month period after beginning a peer education intervention, similarly hepatitis C screening increased from 9 to 46, and numbers were also increased for HIV screening and hepatitis B vaccinations [89].
	In a study on parenting skills [90] statistically significant improvements in self-reported father/ child contact were seen (mean difference 41.3, 95% CI: 6.47, 76.13).
Confidence	One study [69] reported no significant differences.	No statistically significant effect of the peer intervention in three studies [58,80,95] (WMD 1.51, 95% CI: −0.84, 3.86, 3 studies, n = 83, I2 = 81%).	Trained individuals reported that they were ‘giving something back’, doing something constructive with their time in prison and being of benefit to the system; this consequently had an effect on individuals’ self-esteem, self-worth and confidence [19,23,32,36,56,61].	Volunteers experience increases in self-esteem and self-worth as a result of the service they provide to others [72,102]. Evidence also suggests prisoners gain an enhanced sense of compassion for other people [72,102] and being prison hospice volunteers allows individuals ‘to give something back’ [77].		Health trainers seemed most confident in signposting to exercise, smoking cessation and drugs services and least confident in signposting to self-harm, immunisation and dental services [54].	Peer training: One study [71] reported s mall but statistically significant negative effects of the intervention on self- esteem (MD −2.15, 95% CI: −4.20, −0.10), measured with the Rosenberg self-esteem scale, and optimism (MD 1.30, 95% CI: −0.83, 3.43), measured with the life orientation text.
		Qualitative evidence suggested improvements in the peer deliverers’ self-esteem, self-worth and confidence as a result of the role [53,58,79-81,96].The sense of being trusted by the prison authorities to counsel and support prisoners in distress was reported to enable peer deliverers to regain their self-respect [23,79].The notion that peers became more empowered consequentially was alluded to [58,79,80,95,96].				Qualitative research [54] found that training as a health trainer had been a huge boost to prisoners’ confidence, self-esteem and self-worth, reported by key staff. There was also evidence of health trainers bolstering other prisoners’ reported self-esteem and confidence through listening and supporting individuals [54].	Peer outreach: Qualitative evidence suggested that peer volunteers felt that their role was worthwhile and that they were making a difference to the health of the prison population [85].
							Peer advisers: Two studies reported increased self-esteem and self-confidence, coupled with peer deliverers reporting that they were building a work ethic and a sense of control over their lives [57,59]. The role was perceived by the volunteers to be worthwhile and purposeful as well as enabling social interaction with others and offering ‘structure’ to the prison day [57]
Mental health	No effect on anger or frustration in the parenting skills study [92], either immediately post-intervention (MD 0.20, 95% CI: −1.42, 1.82) or at longer follow-up (MD 1.40, −0.03, 2.83).	Peer support was reported to have helped prisoners either practically, emotionally, or both [58] and in one study it was demonstrated that this type of intervention could be particularly beneficial for prisoners during the early part of their sentence [62]. Those who had used peer support reported using it as an avenue to vent and to overcome feelings of anxiety, loneliness, depression and self-injury [58,79,96] and there were indications that this may be potentially beneficial in preventing suicides in prison [53].	Three studies [32,36,56] reported an impact in reducing depression and anxiety in distressed prisoners and improving their mental state. There is anecdotal evidence that suicide and self-harm is reduced as a result of the support offered by peers acting in this role. A fourth study [37] found 44% of users of the Listener scheme reported that they always felt better after confiding in a Listener, while 52% felt better at least 'sometimes'. 84% said they had always found the experience helpful.	In one study, prison volunteers described life enrichment, growth, and coming to terms with their own mortality as a result of their involvement [64]. Moreover, the recipients of one of the programmes suggested how the volunteers had supported them and enabled them to overcome states of depression [64].			Peer training: One study [71] found no statistically significant effect of the intervention on anger (mean difference −4.01, 95% CI: −9.40, 1.38), measured with the anger expression scale.
			Four studies [32,56,61,92] related the emotional burden of listening to other prisoners’ problems and issues. Discussions relating to suicidal intentions and other distressing topics could be particularly burdensome for peer deliverers to manage. There were also reports of peer deliverers experiencing ‘burnout’ and mental exhaustion as a result of the demands placed on their time by other prisoners [56,92]				Peer support and counseling: One study [29] looked at the effects of peer support (Narcotics Anonymous meetings) and counselling (12 step programme), compared to peer support alone (NA meetings only) on mental health, namely coherence, meaning in life, anxiety, depression and hostility. Improvements with the combined interventions were seen in all outcomes: coherence (mean difference −0.31, 95% CI: −0.48, −0.14), meaning in life (MD −0.42, 95% CI: −0.65, −0.19), anxiety (MD −0.42, 95% CI: −0.66, −0.18 ), depression (MD −0.35, 95% CI: −0.52, −0.18 ), hostility (MD −0.11, 95% CI: −0.18, −0.04).
Preference	In an American HIV RCT [84], 68% preferred to be taught by an inmate with HIV versus 11% who preferred a HIV/ AIDS educator.
Additional themes	Qualitative evidence suggested that peer deliverers found the experience personally rewarding, giving their time in prison meaning and purpose [55,68]. In one study, this included improved listening and communication skills as a result of their participation [90]. Other [55research suggested that being a peer educator also enabled the difficulties of prison life to be off-set through the supportive network of other trained peer educators.	No statistically significant effect was seen on prisoners’ perceptions of the prison environment in the pooled results of 3 studies [58,80,95]			16/22 (73%) participants released for at least 12 months were employed, enrolled in an educational program or had completed the application process for disability benefits.	Prisoner outcomes: Issues most likely to be discussed with health trainers were reported in one study [54] to be exercise, weight and healthy eating.	Peer observers: One controlled study [86] found a statistically significant decrease (t(71.55) = 2.14, p = 0.036) in the mean number of hours on watch following the implementation of the Inmate Observer Programme.
		One study [79] found that 81% of 35 respondents valued the existence of the Peer Support Team. Another study [81] reported that inmates were very satisfied with the quality of the information delivered by PST members. Expectations of the PST were also well met.			18/22 (82%) participants who had been released for at least 12 months had secured treatment, transitional housing or a permanent place to live.	Onward referrals: Health trainers in one study [54] were most likely to refer clients to gym staff or healthcare staff. Referrals were also made to Counselling, Assessment, Referral, Advice, and Throughcare services (CARATS), counsellor, dentist and optician.
		Staff reported that PST members were effective in handling crisis interventions, providing services to inmates and serving as role models.
		In one study [81] PST members estimated that they provided support to others of 3–5 hours per week on average.
		In several studies [23,58,79,80,96], there was indication of peer deliverers gaining better self-awareness and perspective on their life as well developing the skills to deal with their own health and offending issues. There was limited information on the impact that the role would have on future re-offending. Only in one study [23] was it suggested that the experiences of being a peer support worker would be beneficial in reducing the likelihood of re-offending.
		The demands placed on peer support worker/counsellors by other prisoners gave individuals a sense of purpose in prison [23,53,94] and this was beneficial for combatting boredom while serving the prison sentence [23,53].However, there were indications that the role could be challenging and onerous and the burden of care of supporting many prisoners could be problematic [53].