1 Introduction

Among all ages, youth between 12 and 18 years have the highest rates of victimization, and approximately one-third are victims of violent crime by a family member [1]. Family violence including physical abuse, sexual abuse, and exposure to intimate partner violence has been linked to increased mental health problems and substance abuse in youth, putting them at risk for lifelong health problems [2, 3]. However, other intersecting risks such as low socioeconomic status (SES) and discrimination also put youth at risk [4]. Early intervention can make the difference for these at-risk youth; however, engagement with such youth is often a challenge [5]. Identifying effective strategies and interventions for engaging with at-risk youth could support their health and well-being over the lifespan.

1.1 Genesis of risk for youth

The connection between early childhood abuse and mental health concerns later in life was well established by Felitti et al.’s [6] landmark study of Adverse Childhood Experiences (ACEs). Examples of ACEs include physical and emotional abuse and neglect, sexual abuse, and exposure to a traumatic household such as interparental violence, mental illness or substance abuse, and lack of food or clothing associated with low socioeconomic status (SES), all before the age of eighteen years [6]. A higher number of ACEs is associated with more symptoms of mental health problems, and clinical depression and anxiety later in life [7, 8]. The number of ACEs a person is exposed to also demonstrates a graded relationship with alcoholism in adulthood that is independent of having a parent who abused alcohol [9]. Each ACE increases the likelihood of early illicit drug use between two- and four-fold, and individuals with five or more ACEs are seven to ten times more likely to develop problems associated with drug use, drug addiction, and parenteral drug use [10]. Systematic reviews demonstrate that exposure to more ACEs is associated with increased risk for the leading causes of death including cardiovascular conditions and inflammatory disorders [11] and wide-ranging physical health and mental health problems over the lifespan [12, 13].

Childhood trauma, such as abuse and neglect, can cause neurological changes that impact development and cognition, increasing the risk of mental illness and substance use disorders later in life [14]. Stowkowy et al. [15] found that youth with mental illness experienced more trauma and bullying, and bullying has also been associated with increased rates of substance abuse [16]. Additionally, youth are more at risk of developing an anxiety disorder if a parent has a mental illness such as anxiety, depression, melancholic personality traits, schizophrenia spectrum illness, or a history of psychiatric hospitalizations [17].

Youth are also vulnerable to the impacts of social determinants of health (SDH), which are non-medical circumstances such as SES, social norms, and policies that influence health and well-being [4, 18]. Low SES has been associated with increased rates of child maltreatment such as abuse and neglect [19]. Other SDH’s, such as discrimination, have been associated with mental health and substance use disorders. For example, sexual minority men and women that experienced discrimination had higher odds of developing a substance abuse or mood disorder, respectively, than their sexual minority counterparts that never experienced discrimination [20]. It is important to note that lesbian, gay, bi-sexual and transsexual (LGBT) youth are at increased risk of depression due to stigma and victimization due to discriminatory experiences such as family rejection, bullying, and lack of social acceptance [21]. In summary, youth are at-risk from intersecting impacts of ACEs including family violence, child abuse and neglect [18]. These stand to increase vulnerability to a host of poor mental and physical health outcomes over the lifespan [11,12,13].

1.2 Importance of early intervention

Early intervention has been shown to reduce the chronicity of mental health problems [22], decrease youths’ drug and alcohol abuse [23], and limit the impacts of family violence on youth’s development and well-being [24]. Youth engagement in the intervention is a critical component of treatment success; however, some youths are particularly difficult to engage [25]. The concept of engagement is inconsistently defined across the literature, however for the purposes of our review we define engagement as initiation, attendance, or participation (i.e., actively participating in activities, conversations, or therapeutic bonding) with an intervention. Barriers to engagement include stigma (e.g., feeling judged or blamed), lack of awareness, failed prior treatment, and lack of motivation to initiate treatment [26]. Additionally, Radez et al. [5] identified four major themes related to the seeming lack of engagement by youth with mental health services: 1) Individual factors such as limited mental health knowledge, 2) Social stigma and embarrassment, 3) Perceptions of relationship with provider, including confidentiality and trust, and 4) Systemic and structural barriers, including cost and logistics such as transportation. Historically, heterosexual males and ethnic minorities have been the least likely to utilize mental health and substance use services [27,28,29]. Identifying strategies that target these barriers is essential to facilitating youth engagement and promoting positive treatment outcomes.

With increasing recognition of the impacts of family violence, mental health problems, and substance use on youth well-being, interventional programs are being developed to address and mitigate their effects. Thus, it is critical to identify ways to overcome obstacles and promote engagement with these programs to maximize their reach and success. As such, this review of the literature sought to assess the question: What are effective strategies and/or interventions to engage youth at-risk for family violence, mental health difficulties, and substance abuse problems?

2 Methods

2.1 Search strategy

First, we searched the literature to identify recent articles focused on engaging youth identified as at-risk for mental health difficulties, substance abuse, or family violence in interventions. Four articles were identified as seed articles and were used to create key terms for the search strategy. Then, a search strategy was developed for APA PsycINFO with the aid of an academic librarian and modified to fit other electronic databases [see Additional file 1]. Searches contained a combination of terms for youth (i.e., adolescent), engagement (i.e., engage, participate), mental health, substance abuse, or domestic violence (i.e., depression, drug abuse, abuse), and interventions (i.e., program). Searches were run in PsycINFO, CINAHL, SocINDEX, Family & Society Studies Worldwide, and Social Work Abstracts on June 16th, 2021.

2.2 Study selection

Following the search, all retrieved articles were uploaded into Covidence [30] and duplicates were removed, generating 2421 titles and abstracts to screen. Eight additional abstracts were identified by reviewing the reference lists of other literature reviews retrieved during the electronic database search. Two reviewers piloted the eligibility criteria on 50 random titles and abstracts to gain a 96% inter-rater reliability. Following the calibration exercise, titles and abstracts were screened by one independent reviewer for assessment against the inclusion criteria for the review. Thirty-two potentially relevant studies were retrieved in full text and uploaded to Covidence. Full texts were assessed in detail against the inclusion criteria by three independent reviewers. Overall, 19 studies were excluded during full-text review. Twelve studies were excluded due to the wrong patient population, three had the wrong study design, one did not describe engagement strategies, one was the wrong intervention, one had the wrong outcomes, and one had the wrong route of administration. The final sample included 13 studies that met all eligibility criteria and were included in the rapid systematic review (Fig. 1).

Fig. 1
figure 1

Adapted from Page et al. [32]

PRISMA Diagram of Study Selection. The PRISMA flow diagram for the rapid systematic review detailing identification through databases, abstracts and full texts screened to be eligible/ineligible, and full texts included/excluded.

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2.3 Inclusion criteria

The authors sought to include studies where youth were identified as at-risk for family violence, mental health difficulties, or substance abuse. Studies had to examine youth-targeted strategies aimed at increasing engagement with interventions. All methods of delivery of engagement strategies were included (i.e., digital, face-to-face, group, recreational). Identified interventions had to be specific to the social sciences. The target population for included studies was 12 to 18 years old; however, studies with different age ranges were included if participants’ mean or median age fell into this age range. Participants could be of any sex or gender, ethnography, or SES. Studies could be from any country. Both qualitative and quantitative studies were included.

2.4 Exclusion criteria

Our study builds on a similar review published by Dunne et al. [31] that examined strategies to engage youth with mental health and substance use interventions. Their search was conducted in August 2014 and included articles published within the previous 10 years. To prevent overlap in retrieved articles, studies published prior to 2015 were excluded from our review. Papers including meta-analyses, systematic reviews, scoping reviews, and literature reviews were excluded, however their reference lists were reviewed for relevant articles. Non-peer reviewed papers, grey literature (e.g., newspaper reports), and articles not published in scholarly journals were excluded. Non-English articles were also excluded.

2.5 Data extraction and synthesis

Two reviewers developed a data extraction form and relevant characteristics were extracted by one reviewer. Frequency counts were done based on the extracted data and thematic analysis was used to group engagement strategies into five categories: technology-based, experiential therapy-based, counselling-based, program-based, and other.

3 Results

3.1 Study characteristics

Combined, the 13 studies examined 2,527 at-risk youth. Six studies were descriptive [33,34,35,36,37,38], four were classified as experimental [39,40,41,42], and three were quasi-experimental [43,44,45]. Seven articles studied youth at-risk for mental health difficulties [33,34,35, 37,38,39,40], while two examined youth at-risk for substance abuse [41, 44]. Three studies included youth dually at-risk for both mental health and substance abuse disorders [42, 43, 45]. One study included youth that were at-risk for both mental health issues and domestic violence [36]. The youngest participants analyzed were 11 years old and the oldest were 25. The mean age of participants in nine (69%) of the studies fell between 14 and 16 years old. Twelve of the 13 studies included participants of mixed genders (i.e., female, male, intersex). One study only included female participants [36].

A majority of the articles (7/13) reported that the greatest proportion of their sample was Caucasian [33,34,35, 39, 40, 42, 44]. In three studies, 50% or more of participants identified as Hispanic [41, 43, 45]. One article had a majority of Israeli participants [37] and one had equal numbers of Caucasian and African American participants [36]. One study did not record the ethnicities of their participants [38]. Eight studies (out of 13) were conducted in the United States [33, 36, 40,41,42,43,44,45], two were from the United Kingdom [34, 38], one was from Australia [35], one was from New Zealand [39], and one was from Israel [37]. Five of the 13 studies reported sample sizes greater than 100 [33, 35, 38, 41, 44], while eight reported sample sizes of less than 100 [34, 36, 37, 39, 40, 42, 43, 45].

3.2 Engagement strategies

3.2.1 Technology-based strategies

Three studies reported on technology-based engagement strategies [33, 34, 40] (Table 1). Two of the identified strategies used texting or short-message service (SMS) messaging as ways to engage participants [34, 40]. One study used texting as a method to ‘collect’ young people at-risk for mental health difficulties that did not attend scheduled vocational placements or therapeutic sessions [34]. This strategy was part of a larger developmental psychodynamic model meant to address both the ‘healthy’ and ‘destructive’ parts of young people that are difficult to engage. Contacting youth that missed scheduled interventions via texting was theorized to encourage the ‘healthy’ aspects of their personality to engage in treatment and push away any ‘destructive’ thoughts or behaviours that discouraged participation. Engagement was assessed as the number of sessions attended out of the number of sessions offered. Using this strategy, three-quarters of youth engaged with the program for over eight weeks and average session attendance was 82%; significance of the results was not reported.

Table 1 Technology-based engagement strategies
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Another study examined the TechConnect strategy, which utilized digital messaging to proactively engage youth with treatment, sending a weekly SMS message 48 h prior to each of eight therapeutic sessions [40]. SMS messages provided details on the session, such as time and place, and were specifically designed to target decision making and increase engagement by referencing perceived benefits, barriers, and self-efficacy. Furthermore, parents received phone calls 48 h prior to sessions one, two, and five. Engagement was measured by session attendance. Youth that received TechConnect attended significantly more (p < 0.05) treatment sessions, attending an average of 91.3% of the eight sessions compared to the average 66.3% of sessions attended by youth that did not receive TechConnect.

One study used call-transferring to engage youth at-risk for suicide with crisis counselors as part of a risk-management protocol [33]. During three-month follow-up telephone interviews with youth that presented to an emergency department for suicide risk, interviewers that identified pre-specified risk triggers during the interview (i.e., “Have you thought about how you might kill yourself?”) transferred youth to a crisis counselor at a crisis hotline. Engagement was operationalized as successful call connection, duration of the call, and information sharing with the crisis counselor, such as coping strategies and sources of distraction and support during safety planning. Information sharing has been associated with reduced suicidal behaviour and increased treatment engagement [46]. Ninety-four percent of call connections were successful, and the average duration of the call was 13 min [33]. Eighty-four percent of youth shared information about coping strategies and 35% discussed sources of support over the course of the call. Notably, participants’ gender, race, ethnicity, and age did not produce significant differences (p > 0.05) in engagement with the crisis counselor. Additionally, engagement did not differ significantly (p > 0.05) based on clinical characteristics such as a history of suicidal thoughts or behaviours, aggression, or substance use.

3.2.2 Experiential therapy-based strategies

Experiential therapies focus on promoting a strong and trusting relationship between the therapist and the client, as well as processing both conscious and unconscious emotions and experiences to help clients better interact with the world and act authoritatively in their lives [47]. These therapies involve tools or activities, such as crafts and role-playing, that allow clients to re-enact past experiences in order to process them. Three articles retrieved from our search used different experiential therapies to engage clients in therapeutic sessions [37, 43, 45] (Table 2). One examined the role of sandplay therapy in engaging youth dually at-risk for mental health difficulties and substance abuse in an intensive outpatient treatment program [43]. Although sandplay therapy was used in conjunction with adventure therapy, art therapy, and recovery management as engagement strategies, this article focused solely on the influence of sandplay therapy. Sandplay therapy is a trauma-informed therapy, and the multi-sensory and symbolic nature of the sand is believed to support healing [43]. Engagement was evaluated in focus groups following treatment. Many youths considered sandplay therapy to be the most helpful part of treatment and staff described it as creative and engaging. Clients looked forward to sandplay sessions and actively engaged in conversations about their therapy.

Table 2 Experiential therapy-based engagement strategies
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In another study, psychodrama was used as an engagement strategy [37]. Psychodrama allows clients to role-play as themselves or significant people in their lives to re-enact experiences and explore coping strategies and different ways to confront problems [48]. Dramatic engagement was defined as the extent to which an individual participated in the dramatic activities [37]. Dramatic engagement significantly increased over the psychodrama sessions (p < 0.01) and had the highest odds of predicting increased cognitive-behavioural exploration in therapeutic sessions (p < 0.001), followed by increased in-session therapeutic changes (p < 0.001), then decreased in-session resistance (p < 0.1).

The third study examined the efficacy of animal-assisted therapy (AAT) in increasing treatment participation among youth with both psychiatric and substance abuse disorders [45]. AAT has been introduced into therapeutic sessions on the theoretical foundations that animals reduce anxiety, promote self-efficacy, and may serve as both attachment figures and transitional objects [49]. Treatment participation was operationalized as the number of treatment sessions attended [45]. Across 16 sessions, the AAT group attended significantly more sessions than the non-AAT group (p = 0.0072).

3.2.3 Counselling-based strategies

Although they can be employed as standalone therapies, counselling methods such as motivational interviewing (MI) have been used as engagement strategies before or during other interventions to better understand and overcome barriers to treatment [50]. Three retrieved articles used counselling-based engagement methods [36, 38, 39] and two articles incorporated MI into their engagement strategy [36, 39] (Table 3). MI focuses on creating a conversation between client and therapist to enhance the client’s motivation and commitment to change [51]. One study used MI as a pre-treatment engagement strategy for group cognitive behavioural therapy (gCBT) [39]. Engagement was evaluated by attendance at therapy sessions, initiation of gCBT treatment, and readiness for treatment. Clients that received MI attended significantly more therapy sessions than those in the control condition (p = 0.01). Ninety-six percent of the MI group-initiated treatment compared to only 80% of control group participants (p = 0.02). Additionally, MI participants had significantly higher treatment readiness ratings than the control group (p = 0.01).

Table 3 Counselling-based Engagement Strategies
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Another study combined MI with dialectical behaviour therapy (DBT) commitment strategies, cognitive behavioural therapy (CBT) engagement strategies (i.e., clarifying roles of service provider, problem solving attendance barriers, creating a collaborative relationship), and cultural adaptations to maintain treatment engagement and counter resistance [36]. The cultural adaptations and DBT commitment strategies were not clearly described in the paper. Caregivers were also incorporated in treatment processes. This study focused on two case reports: one of treatment success and one of treatment failure. In the successful case, the patient (“Ava”) actively participated in discussions and role-play and implemented coping skills outside of treatment. In the unsuccessful case, the patient (“Jen”) was initially engaged in role-play, however she inconsistently used coping skills outside of therapy. Jen’s engagement decreased over the course of treatment, and she ultimately resisted engaging in the narrative work designed to process her trauma. Jen stopped attending therapy sessions and did not complete treatment.

The third study focused on a mentalization-based therapeutic approach to both engage youth and act as a treatment strategy itself [38]. Mentalization is the way people understand their own and each other’s mental processes and states [52]. In this study, engagement was defined as the percentage of kept appointments [38]. Well engaged and less engaged youth did not differ in the number of appointments offered, however treatment duration (p = 0.022) and time between appointments (p < 0.001) were significantly longer for the less engaged group. Once engagement was at 80% or above, youth identified as more easily engaged had a significantly shorter median duration in treatment than less engaged youth (p = 0.022) and had fewer professionals involved in their care (p = 0.027). Clinically, the less engaged groups had significantly higher negative symptom scores in the Early Psychosis Support Service (EPSS) cohort (p < 0.05). Younger youth were more easily engaged (p = 0.023).

3.2.4 Program-based strategies

Some interventions have developed larger multi-faceted programs to better engage youth participants [41, 42, 44] (Table 4). One study examined the Treatment Readiness and Induction Program (TRIP) as a method to engage youth and increase readiness for substance abuse treatment [41]. TRIP incorporates modules, activities, and guide maps or analytic schemas to promote problem recognition and decision making in youth. Engagement was operationalized as youth’s perceptions of treatment participation, treatment satisfaction, rapport with counselors, and peer support during treatment. Youth that received TRIP in addition to standard operating procedure (SOP) were significantly more engaged than those that only received SOP (p < 0.05). Youth that received TRIP significantly increased in domains including treatment satisfaction, rapport with counselors, and peer support over the course of treatment (p < 0.01—0.05) There was no significant difference in treatment participation between groups (p > 0.05). Notably, males reported significantly higher engagement scores (p < 0.05) than females.

Table 4 Program-based engagement strategies
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Another study compared the use of a mutual aid program as both the engagement strategy and substance abuse intervention with a control group [44]. The focus of the mutual aid group was to help youth develop prosocial skills to promote healthy interpersonal relationships in order to enhance academic success, decrease substance abuse, and increase participants’ coping skills. Leaders modelled communication skills, affective skills, and problem-solving skills meant to be used in group interactions. Engagement was measured over five domains similar to those measured by Knight et al. [41], including: attendance, contributing to the group, relating with others (both the leader and other group members), working on one’s own problems, and working on other group members’ problems. Total group engagement increased significantly across sessions (p < 0.001) and all five measured domains of engagement increased significantly throughout treatment (p < 0.001).

Walker et al. [42] developed Achieve My Plan (AMP), consisting of pre-meeting prep sessions, as an engagement strategy for their already established Wraparound service. Wraparound is a mental health and/or substance abuse intervention that focuses on uniting youth, family, and service providers as a team to collectively establish a treatment plan and meet to address perspectives, needs, and challenges throughout treatment. AMP consisted of youth engaging in three individualized prep sessions with a coach that focused on identifying strengths and goals, setting the meeting agenda, and preparing for meeting participation. Compared to the control group that underwent Wraparound as usual, the AMP group showed significantly increased scores in domains measuring active participation and engagement during team meetings. Youth that received AMP were significantly (p < 0.05) more likely to lead the entire segment, interact with the team positively, and make a ‘high quality’ contribution during Wraparound team meetings.

3.2.5 Other engagement strategies

One retrieved study did not fit well into the other categories of engagement strategies [35] (Table 5). This study described the Assertive Mobile Youth Outreach Service (AMYOS), an assertive community treatment (ACT) that used mentalization-based treatment similar to Griffiths et al. [38]. AMYOS’ engagement strategies focused on providing practical flexible support for at-risk youth that included attending centres for social security payments or medical appointments with their 13- to 19-year-old clients [35]. Additionally, AMYOS met in locations convenient for participants and there was flexibility in the frequency and time of weekly appointments. Mean youth engagement scores increased significantly over the course of treatment (p < 0.001). Additionally, over time youth engaged significantly more with support networks external to AMYOS such as their general practitioners and education (p < 0.001).

Table 5 Other engagement strategies
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4 Discussion

The purpose of this review was to identify and examine the efficacy of various engagement strategies for youth at-risk of family violence, mental health problems, and substance abuse. In total, 13 articles on engagement strategies were examined with some having more success than others. Four of the five types of investigated strategies increased at-risk youth engagement. Technology-based strategies included personalized text messages and call transfers to a crisis hotline; both showed high levels of youth engagement and texting-based strategies were considered easy to implement [33, 34, 40]. Interestingly, there were no differences in engagement between genders, race, ethnicity, age, or clinical characteristics when using call-transfer [33]. The experiential therapies (sandplay therapy, psychodrama, and animal-assisted therapy) received positive feedback from youth [37, 43, 45]. All three in-person program-based strategies increased scores of engagement measures beyond attendance, such as participation, rapport with peers and counselors, and working collaboratively with others [41, 42, 44]. Additionally, the AMYOS study increased both treatment engagement and engagement with other support networks [35]. However, the counselling-based strategies differed in their success. The study examining MI found increased rates of treatment initiation, attendance, and readiness of youth [39]. Another focusing on mentalization-based therapy found no significant differences in engagement based on gender, but younger youth were significantly better engaged [38]. However, Grefe et al.’s [36] study that used MI, DBT, and CBT had mixed results with one participant’s engagement increasing while another’s decreased. Due to the small sample size, the overall success could not be determined.

A similar review of research published between 2004 and 2014 was published in 2017 that explored effective engagement strategies for mental health and substance use interventions for youth [31]. We sought to provide an update to this work by restricting our results to studies published after 2014. They included 40 studies, reviews, and program reports published between 2004–2014 [31]. Studies published prior to 2004, the year Facebook was launched, were not included to account for the modernization of interventions and engagement strategies in the digital era. Their review uncovered strategies focused on: 1) youth empowerment through program development; 2) engagement through parental relations; 3) engagement through technology; 4) engagement through medical or mental health clinics; 5) engagement through school; and 6) engagement through social marketing. Similar to our findings, their searches retrieved a broad variety of interventions and approaches and concluded that there is no single best approach to engaging youth and that the greatest results may be seen in combining different approaches based on individual and community needs.

Technology-based strategies showed high engagement efficacy. Similar to the finding that SMS messaging between treatments increased attendance and engagement [34, 40], Dunne et al. [31] also found that between-treatment texting increased treatment plan adherence and client-patient relationships. Call transfer showed no significant differences in engagement based on gender, race, ethnicity, or age [33]. This contradicts previous findings that males, ethnic minority groups, and those with lower SES are less likely to engage with crisis hotlines [53]. Additionally, previous studies have reported age-related differences in attendance, satisfaction, and rates of dropout with mental health and substance abuse interventions [54,55,56]. The apparent reduction in engagement barriers across demographics may be because youth do not engage face-to-face with a crisis counselor in this intervention, thus making it easier for historically less engaged groups to engage with the crisis counselor [33]. This is supported by Dunne et al.’s [31] review which found that the anonymity provided by online interventions increased males’ likelihood to engage with them over traditional care. Additionally, the finding that engagement did not differ significantly based on clinical characteristics suggests that this strategy is effective at engaging youth with varying clinical histories [33]. Overall, these findings suggest that the use of technology-based strategies can overcome known barriers to engagement and may aid in attracting and retaining at-risk youth from a variety of clinical and demographic backgrounds. Moreover, technology-based interventions were also reported as highly accessible by youth and easily implemented by practitioners [40]. As such, interventions developed for at-risk youth should consider adopting a technology-based strategy to improve youth engagement and expand their program’s reach.

All three experiential therapies (sandplay, psychodrama, and AAT) were associated with increased engagement among youth participants. However, Freedle et al. [43] measured engagement using focus groups with practitioners and youths. This made it difficult to quantify the extent to which engagement was increased as only select quotes from focus groups were reported. Nonetheless, these results are consistent with the finding that experiential therapies can significantly increase treatment engagement and retention among high-risk youth in family therapy [57]. Additionally, pre-treatment experiential therapy has been found to increase alliance formation between client and therapist and increase client disclosure, a marker of early engagement, during treatment for depression [58].

The counselling-based strategies showed the greatest variability in engagement success. The study examining mentalization-based therapy determined that levels of engagement did not affect the number of appointments attended, but less engaged youth had longer treatment durations and more professionals involved in their care [38]. Additionally, younger participants were significantly better engaged. The strategy that used MI alone was associated with greater attendance, initiation, and treatment readiness [39]. Comparatively, the study that used MI combined with DBT and CBT strategies had limited success in engaging participants [36]. However, this study was a case report and only showcased one positive and one negative outcome (n = 2) from a larger study (n = 9). Engagement success was not reported for the larger study and therefore it is difficult to assess the efficacy of this strategy in a larger sample. The authors hypothesized that the disparity in treatment engagement was due to differences in caregiver participation in other aspects of treatment. However, due to the small sample size it is unclear if other factors influenced success.

All three program-based engagement strategies were correlated with increased engagement and proved to be effective [41, 42, 44]. Program-based engagement strategies such as mutual aid groups and peer support have long been used in substance abuse treatment and mental health care [59,60,61]. Peer support has also been identified as a protective factor against the long-term effects of childhood exposure to intimate partner violence [62]. Additionally, the use of Wraparound models for mental health and substance abuse interventions has expanded rapidly over the past few decades [63]. However, these strategies may be more burdensome to implement when compared to technology-based strategies because they require program development and facilitator training [41]. Nonetheless, beyond our finding that these types of strategies increase participant engagement, they may also improve the efficacy of interventions. For example, program-based strategies reduce the use of residential treatment and hospital stay length for mental health care as well as the number of days individuals use substances [63,64,65]. Thus, if sufficient resources are available, the implementation of these engagement strategies may not only increase youth engagement with interventions but also their overall success.

Finally, Daubney et al.’s [35] study found increased engagement with both AMYOS treatment and external support networks. However, similar to the program-based engagement strategies, AMYOS may be more burdensome to implement as it would require increased flexibility and availability from staff, as well as increased staff responsibilities [35]. When examining engaging youth through medical or mental health clinics, Dunne et al. [31] found similar results and reported that factors such as convenience of location and flexible hours increased engagement and help-seeking. Similar studies have found that the flexibility and convenience of social services, such as an easy to find and access location as well as appointment times that are convenient for youths’ schedules, increases service utilization among youth [66]. While little evidence is available to date on the effects of these youth-friendly adaptations on retention rates for social programming, within the healthcare sector studies have found that youth are more likely to be retained in HIV care at clinics with youth-friendly structures [67, 68]. Therefore, incorporating flexible elements into mental health, substance abuse, and family violence interventions may help to recruit, engage, and retain hard-to-reach at-risk youth.

4.1 Limitations

There is considerable heterogeneity (e.g., sample size, demographics, location) among the studies included in this review. As a result, it is difficult to compare engagement strategies to determine if one is more effective than the others or if a specific type is preferred by youth. Comparing strategies is particularly challenging due to the variation in definitions of engagement and measures used among studies. Many articles used session attendance as a crude measure of participant engagement. However, other articles used more detailed measures such as rapport with counselors and involvement with peers [41, 44]. Detailed measures of in-session participation are useful indicators of clients’ willingness or resistance to therapy, and overall engagement with the process of change [41]. Future research should adopt in-depth definitions and measures to better investigate aspects of engagement beyond session attendance such as the Client Evaluation and Treatment (CEST) self-rating instrument developed by Joe et al. [69]. Initially created to assess patient attributes and engagement with drug abuse treatment, the CEST measures domains including treatment motivation, psychological and social functioning, social network support, and treatment engagement. The CEST has since been modified for adolescents in substance abuse treatment by Knight et al. [70]. Further modification of the CEST for other types of adolescent programming, such as domestic violence and mental health care, or adoption of other standardized tools will also improve consistency within the field. Ultimately, this will facilitate comparison of engagement strategies across studies and the determination of gold standard methods.

All studies but one [37] were performed in Western countries, limiting the generalisability of the results. This is likely due to the exclusion of all non-English articles. Moreover, the greatest proportion of participants in a majority of the studies were Caucasian, limiting the generalisability of the efficacy of these strategies to youth of different ethnicities.

One study had a small sample size, which impeded our ability to gauge the success of the intervention [36]. None of the retrieved studies directly compared different engagement strategies. Additionally, no studies assessed differences in engagement based on program length. Research into online learning, in particular massive open online courses, has found that course duration can impact learner engagement [71]. For example, participant engagement in an online course was greater when it was delivered in two three-week blocks rather than one six-week course [72]. In addition, Anutariya and Thongsuntia [73] found that short and medium-length courses were significantly better able to engage learners and had reduced participant dropout. As such, future research should investigate how variables such as program length can impact youth engagement in the context of substance abuse, mental health, and domestic violence interventions. Future studies should also assess whether the efficacy of engagement strategies themselves can vary based on these intervention specificities. This information will assist programs in choosing and adapting engagement strategies to best fit their interventions and the populations they aim to serve.

5 Conclusion

Many of the engagement strategies retrieved in this evidence assessment were reported to be successful. Technology-based, experiential therapy-based, and program-based strategies, as well as AMYOS, all increased youth engagement. However, counselling-based strategies differed in their success. These findings support Dunne et al.’s [31] conclusion that there is no “best” engagement strategy with at-risk youth. Instead, a variety of strategies have proven effective and can be combined and tailored to fit the individual needs of youth and the resources available to the intervention program at that time.