Overview of included studies

Our searches identified 23 papers (Fig. 1): 22 published papers [33, 67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87], and one ‘grey’ literature study [88]. Four papers were from two studies [68, 69, 77, 85], meaning the findings from 21 studies were synthesised.

Fig. 1 PRISMA diagram. * see Additional file 2: Table S2 for details Full size image

Characteristics of the included papers are detailed in Table 4. In this table, we highlight the differences in these included studies, in terms of setting, participant demographics and intervention/service. Briefly, the 21 studies were conducted between 2002 and 2018 in the USA (n = 11), Canada (n = 7) and the UK (n = 3), involving 462 participants (one study did not report participant numbers) ranging from 18 to 62 years. Three studies focused entirely on women [84, 86, 87], and five involved men only [70, 80,81,82,83]. In the remaining studies, although women were involved, 50% to 84% of participants were male; only one study reported a majority of female participants [75].

Participants’ ethnicity was reported in 17 studies, and, in 11 of these, most participants were from ethnic minority groups. For studies conducted in the USA, most participants were Black, Hispanic, mixed race or Indigenous American. In four of the five Canadian papers that reported ethnicity, most participants were Indigenous Canadian. In one UK study, participants were Polish [88]. Data were collected using individual interviews (n = 13), focus groups (n = 2) and combined methods, including interviews, focus groups and town hall meetings (n = 6). Participants were recruited from a range of services rather than directly from the streets. Ten studies provided insight into participant views of services generally [33, 67, 72, 75, 76, 82, 84, 86,87,88], one study explored a hypothetical intervention [74] and tenstudies examined specific substance use interventions [68,69,70,71, 73, 77,78,79,80,81, 83, 85].

Table 4 Characteristics of included studies (chronological order) Full size table

Study findings reciprocally translated into our a priori categories as follows.

What treatments/interventions are perceived as effective by those using them, and why?

Table 5 provides details of participant experiences with harm reduction and abstinence-based interventions, delivered in different settings. Participants in the study by McNeil et al. [74] discussed the merits of a hypothetical harm reduction intervention drawing on their experiences of other interventions such as Twelve Step programmes.

Table 5 Substance use interventions—participant experiences and perceptions of effectiveness Full size table

Abstinence-based treatment was praised for the provision of peer support and people’s desire to help others, with one participant stating: ‘it does help because you’re around like-minded people’ ([27]; p. 91). Abstinence-based residential treatment was the ‘time out’ from heavy alcohol use and homelessness, with some using it as a safe space to stop drinking for a short period, because ‘Treatment wasn’t really about getting sober’ ([27]; p. 91). Some said that they felt better after enforced abstinence [33]. Less positive, however, was the perception that abstinence-based approaches were not effective because they triggered cravings [78, 83, 85], and did not address the underlying issues affecting substance use and homelessness [33, 71, 73, 74, 78]. Some stated that these approaches were ineffective because they were unable/unwilling to stop using substances, or if they abstained during their programme they returned to using substances on leaving [33, 71, 78].

Housing programmes involving harm reduction approaches, such as Housing First, Managed Alcohol Programmes and transitional housing, were viewed as providing a place of safety and security, with people feeling at home: ‘you feel safe, you feel like you’ve got a warm place to stay, and you know, some home’ ([73]; p. 8). The provision of alcohol within Managed Alcohol Programmes and allowing people to use alcohol within Housing First settings, ensured that withdrawal symptoms could be controlled [73, 83, 85]. Participants also spoke highly of the peer support element of these settings, being around those who have similar experiences and the importance of non-judgemental staff [33, 73, 85]. On the other hand, the availability of alcohol when someone wanted to stop using alcohol was perceived as challenging [33, 71, 85].

Harm reduction approaches were discussed by participants in six studies [33, 70, 73, 74, 79, 83], although, in one case, the intervention which allowed those who use drugs to do so safely in hospital was hypothetical [74]. Participants appreciated trusting, non-judgemental staff, the peer support available to them and being in a place of safety [73, 74, 79, 83]. Reducing alcohol consumption and managing withdrawals from alcohol were also described positively [73]. Some participants spoke of the challenges of being in an environment where alcohol was available when they were keen to avoid drinking: ‘If there is a group of people that are drinking a whole bunch … I reach a certain point, and I’ll excuse myself’ ([33]; p. 94). The tensions between harm reduction and abstinence in a transitional housing setting were discussed, highlighting the mixed messages and confusing policies participants received in a service in which while abstinence was not required, substance use was forbidden on site [79].

In terms of online delivery of harm reduction interventions, the flexibility, user-friendliness and non-judgemental approach of one such intervention, Breaking Free Online, was reported positively by participants [68, 69]. Participants also appreciated the opportunity to develop new skills, such as using computers, and coping strategies:

The convenience of it … it can be done anywhere, if you have got a laptop. You can do it in the middle of the park somewhere on a nice summer’s day, rather than going all the way to [drug agency], catching the bus and travelling all the way up there. ([68]; p.260–261)

However, participants also described occasions when this intervention was less effective, including difficulties in using the programme in communal areas, on poor equipment, or when staff were unavailable to allow access [69].

The findings from these qualitative studies cannot conclude that these interventions are effective for all users, at all times, but offer useful insights into the particular elements of these programmes that participants found beneficial. Further details of participant views of what worked (and did not) are shown in Table 5.

How does effective treatment work from the perspective of people who are homeless?

Across all studies, five factors were identified regarding how substance use treatment was perceived as effective for those experiencing homelessness: facilitative service environments; compassionate and non-judgemental support; the importance of time; having choices; and opportunities to (re)learn how to live.

(i) Facilitative service environments

Participants in 11 studies [67,68,69, 71,72,73,74, 76, 78, 82, 84, 88] discussed the service environment and how it affected their experiences of treatment. In most studies, participants reflected on the positive service environments within harm reduction-oriented services. Service environments could be described as ‘facilitative’ where they had features that enabled health, wellbeing and elements of recovery for those using them. For example, Neale and Kennedy’s [67] participants identified facilitative service environments as those that are friendly, relaxed, clean, warm and offer privacy. Service environments were welcoming when they did not result in (re-)traumatisation by creating feelings of powerlessness [78]. These service environments had staff who were understanding of individual circumstances, well-trained, available and had a respectful attitude:

It’s almost like they’re giving all their trust in you, the workers here, it’s like they trust you … got confidence in you. ([73]; p. 6)

Such positive environments included settings where participants had access to staff who had lived experience of homelessness, substance use or other relevant life events, suggesting that they believed that such staff could relate to them more effectively [72, 78, 82, 84].

The importance of safety was also reported by participants in three harm reduction studies [73, 74, 83], as illustrated below:

People carry knives, there’s fights every night. People are drinking that hairspray and mouthwash … But here that doesn’t happen … it’s a big difference … Yeah, I felt a lot safer. ([73]; p. 5)

Conversely, male and female participants talked about sub-optimal service environments where they felt unable to trust providers [73, 84], did not have access to staff trained in dealing with challenging behaviours or who understood drug and alcohol use [71, 74] or experienced high staff turnover [67]. In Sznajder-Murray and Slesnick’s [84] study, women reported being fearful of having their children removed, and viewed staff as lacking understanding, and being judgemental, disrespectful and disregarding of their own efforts to manage their problems. In another study, women stated that their relationship with staff in an abstinence-based setting was adversely affected by high staff turnover, with participants finding it difficult to explain their situation again to new staff: ‘you can’t pour it all out again’ ([87]; p. 405).

(ii) Compassionate and non-judgemental support

Compassionate and non-judgemental support from staff and peers was the most consistently mentioned component of effective treatment services. It was reported in all but three studies [76, 80, 86], across both harm reduction and abstinence-based settings. Participants talked about the need to feel cared for and treated as individuals, by staff who would listen and be open and honest. Feeling cared for included having staff who looked out for them, provided encouragement, helped them feel accepted, were consistently available, went out of their way to help and who ‘put their heart into helping’ ([84]; p. 7). Compassion was all important, as illustrated below:

Just somebody loving you heals you. Just somebody taking interest in what you’re doing heals you. Just saying that person’s name, taking your time out for them, it makes a person – it fills the soul, it fills the heart. The people here mainly need compassion. ([71]; p. 852)

… you could just show a little more compassion and gentleness. Understand that good people are also addicts … Give them a chance to heal and get better ([74]; p. 689)

Conversely, participants talked about their experiences of feeling mistreated by disrespectful and uncompassionate staff, and being perceived as ‘nothing but a junkie’ ([78]; p. 627), as an ‘alien’ ([67]; p. 202), or as ‘addicts’ and ‘criminals’. Some also reported racism:

Sometimes, when you’re in a hospital … and you’re an Aboriginal person … you know there’s a lot of racism in the hospital … They mistreat you and they don’t care … I think if I was treated equally like the other patients were being treated, like human beings and not mistreated, I would [stay] … treat them for who they are and not just because we’re Aboriginal people and drug addicts. ([74]; p. 690)

Compassion and non-judgemental support included peer, practical and emotional support in harm reduction and abstinence-based settings, as reported in 11 studies [33, 67,68,69,70, 73, 77, 82,83,84,85,86, 88]. Being in close proximity to those with similar circumstances brought people together, providing supportive relationships which were also perceived as helping to prevent relapse for those who were abstinent [70, 73, 77, 82, 83, 85, 86, 88]. Participants talked about feeling at ease with the people around them because they could understand their situations and experiences. Peer support provided inspiration, hope and opportunities to engage with those further along in their recovery journey [67, 82]. In two studies of Managed Alcohol Programmes [70, 73], participants (mostly male) talked about peers as ‘family’:

Everybody seems to support each other … the staff and the clients, they treat you like family … We try to help each other. ([70]; p. 121)

Being compassionate also included realising what people needed and providing it through practical support, including food and non-alcoholic drinks; access to clean clothes and medication, and opportunities for tending to personal hygiene; travel expenses; help with appointments and finding doctors; support with benefits and budgeting, and gaining housing [67, 70, 86]. Neale and Stevenson ( [68]; p. 83) reflected on the varied support needs of their participants, including access to college, employment and housing, and ‘ultimately becoming part of society again’.

Emotional support was also viewed as important by participants in seven studies [33, 67, 69, 70, 82, 84, 88] and included access to formal counselling and support to manage traumatic experiences [67, 82]. Informal emotional support included being able to talk about daily concerns and receiving guidance in a non-judgemental/empathetic manner [67, 70, 84], enabling people to become more positive. Such support was discussed as being required in harm reduction and abstinence-based settings [33, 67, 69, 70, 82, 84, 88].

(iii) Importance of time

Participants talked about treatment needing to be long enough in duration for them to avoid relapse/move into recovery [33, 72, 84, 86, 87]. In two studies [86, 87], participants (all women) reported the need for ongoing support after their abstinence-based treatment ended. Neale and Kennedy and Salem et al. [67, 86] both discussed the benefits of an aftercare programme as a way of ensuring a supportive network to prevent relapse. Lengthy or continuous support was often considered necessary and could be provided in the form of safe housing, such as in Housing First settings. Women in Baird et al.’s [87] study talked about feeling ill-equipped for life outside of a shelter, and were concerned that lack of support after 90 days of an intensive abstinence-based programme would result in relapse. Perreault et al.’s [72] study of a 3-year peer support harm reduction housing programme reported that participants considered this to be of insufficient length:

… [the programme] ends after three years. After, I’m supposed to have studied or worked, but that’s not easy. I don’t know if in three years I’ll be capable of working and finding an inexpensive apartment … it worries me a lot, the ‘after’ here … It took me six months to sober up and another six to stabilise. I don’t count my first year as looking for work or even possibly returning to school, I count it as just coming down to earth … The longer it lasts, the happier I’ll be. ([72]; p. 357)

(iv) Having choices

Enabling people to feel that they had a choice about their treatment was reported as beneficial in seven studies [33, 68, 70, 74, 75, 78, 81]. Participants wanted to be treated as individuals with particular needs and be able to set their own goals, rather than experience a ‘one size fits all’ approach ([63]; p. 334). They described past experiences where they did not feel that they had choices:

They really cover a whole wide gamut … that really gives the individual a lot of options. These other programmes are so set in stone. It’s not even a maze, it’s just a straight line and you gotta follow it, where Help Centre just has some good things and so many different pathways you can take to achieve what you want to achieve for yourself… they want you to know that the focus is on the individual. ([78]; p. 630)

The desire for individualised care means flexibility in service delivery. For example, some participants experienced periods of abstinence in a harm reduction setting (Managed Alcohol Programme) because they were able to choose to stop drinking on their own terms [70]. In another study, the different needs of participants receiving counselling was highlighted: some preferring group settings and others one-to-one [33].

(v) Opportunities to (re)learn how to live

Across 14 studies [67, 69,70,71,72,73,74, 78, 80,81,82,83, 85, 86], treatment was seen as providing opportunities for clients to learn skills to support them to live their lives away from problematic patterns of substance use, which would also help stabilise their lives, including their housing. The majority of these studies were harm reduction-oriented, but there was also a sense of the need for these opportunities in abstinence-based settings. (Re)learning life-skills included using a computer, developing a hobby, cooking or participating in meaningful activities such as art, gardening, group trips and other classes. This provided structure and purpose to the day and enabled participants to build their personal identities, alleviate boredom and distract them from thinking about drugs/alcohol [67, 83, 86]:

The programme is … teaching us to be in a home. You know, not like what we’re used to, out on the street. Like re-learning how to be in a house with responsibilities: got to make your bed, do your laundry, sweep, wash the floor, do dishes, and of course, we’re starting to cook. Most of us I think are just re-learning domestic things that you would normally do in a home. It’s another one of the benefits that we get living here. ([73]; p. 7)

This point echoes findings reported in relation to practical support (see section above) on helping people to re-learn life skills. Evans et al.’s [70] participants talked about the challenges they experienced in learning how to live in a residential, harm reduction setting relating to understanding roles and routines. In another study, men and women highlighted the challenges of learning to live in a Housing First accommodation, highlighting the pressure, either real or perceived, of engaging with harm reduction approaches, as a result of previous negative experiences in other settings where substance use was penalised:

The first year I would crack a beer in my own house and look around for the cops. And, I thought the whole year there was going to be a snag, and I was going to get kicked out for sure. ([71]; p. 849)

There was general recognition that having goals and hope for the future was beneficial. Working on a range of goals was also important [67]. Addressing homelessness and substance use were perceived as essential first steps, but the value of smaller goals was also highlighted [78]. People reported wanting more responsibility for their lives, including seeking employment, reflecting that sometimes they were: ‘still treated like kids … They don’t give us a chance to do it, so we’ll leave here without having that experience’ ([72]; p. 358), although other participants reported having had different experiences: ‘They turned my life around by showing me I’m my own person and helping me realise for once in my life I have choices and decisions’ ([82]; p. 18).

Developing these life skills appeared to require participants to achieve some stability in their lives. There was a sense that effective treatment, both in terms of harm reduction and abstinence-based approaches, helped with this stability through providing structure, routine, autonomy and meaning in life:

I am doing my daily routine quite well, making sure I get up in the morning and don’t just stay up watching shit TV until like four o‘clock in the morning. So I think I’m better now, better equipped to get up and do something during the day, like a normal human being. ([69]; p. 85).

Whilst reciprocally translating findings, a refutational translation gradually emerged relating to the desire for stability. This translation was noted in first-order participant data in 11 studies of harm reduction and abstinence-based approaches [33, 69, 71,72,73,74, 78, 81, 83, 85, 86], but was only specifically noted in second-order author interpretations in five studies [68, 72, 73, 78, 83]. Thus, the level of importance attached to the desire for stability by study participants and authors markedly differed: authors often over-looked this when reporting and discussing their most significant findings, despite its centrality for service users.

Line-of-argument synthesis

From translation of findings across the 21 studies, a new line-of-argument emerged enabling creation of a model illustrating our new understanding of the components of effective treatment from the service user perspective (Fig. 2).

Fig. 2 Components of effective substance use treatment from the service user perspective Full size image

For treatment to be perceived as effective by those experiencing homelessness, several essential components are required: facilitative service environments; compassionate and non-judgemental support, including, if possible, the provision of support by people with lived experience; interventions that are long enough in duration, and offer continuity of support; having choices regarding treatment type (such as harm reduction and abstinence-based interventions); and opportunities to (re)learn how to live. Most importantly, these components should be provided within a service context which enables good relationships, person-centred care and an understanding of the complexity of people’s lives.

Service and treatment environments should be facilitative, staffed by people who are non-judgemental, compassionate, respectful and well-trained. It was apparent in some studies that provision of support by staff with previous lived experience of homelessness and problematic substance use was particularly beneficial to service users and thus has much potential. Services must ensure that they do not increase people’s risks of harm as a result of environments that do not take into account people’s experiences of trauma [89]. Support should be long enough in duration for people to gain stability, to avoid relapse and to move into (self-defined) recovery. Practical, peer and emotional support should be delivered without stigma, where trust, mutual respect and collaboration is fostered between those delivering and using services. It is important to note that, whilst some of these components may appear obvious or even taken for granted, these are not necessarily present or prioritised in current service delivery as we note above. While these key components are not radical concepts in and of themselves, they would, we believe, if implemented and financed consistently, provide a radically different experience for those using services.

Across many of the studies [33, 70, 71, 73, 74, 79, 83], male and female participants appeared to prefer services aligned with a harm reduction philosophy. For many, the culture of harm reduction is providing people with positive experiences of effective treatment. However, there were elements of both harm reduction and abstinence-based interventions that were perceived as effective. The intervention that people engage with will depend on individual circumstances, so access to a range of interventions with opportunities to choose which approach suits them best is required, which is a key principle of harm reduction [36, 40].

There should also be opportunities for people to (re)learn life skills, and partake in activities such as cooking, shopping, budgeting and to access education and employment, to help them reintegrate and grow in confidence, and these should be provided in conjunction with suitable, safe and secure housing. These opportunities should be identified on an individual basis: some may need parenting skills or knowledge on how to build and sustain relationships; others may need skills on sustaining housing. This requires goal setting and realistic timescales. While not discussed by participants in the included studies, occupational engagement can also improve outcomes for those experiencing homelessness [90].

For many, engaging with treatment will be challenging, so service providers must understand the complexity of people’s lives, and how their circumstances will affect engagement. Providing these key components within the context of person-centred care is essential. A facilitative environment, enabling people to develop trust and relationships with staff, should enable engagement with treatment and activities.