A substantial proportion of university students experience mental health disorders and low psychological well-being (1–5), and research demonstrates a higher prevalence in university students compared with the broader young adult population (18–24 years) (1, 5). Internationally, 31% of university students reported symptoms of one or more of the following conditions–anxiety, mood or substance disorder–in the last 12 months (6). Data from Australian and Italian surveys report that 36–65% of tertiary students experienced high or severe psychological distress (1, 7, 8). Mental ill-health and psychological distress adversely influence student participation, engagement, and performance, and can also negatively affect longer-term outcomes such as employment, income and relationships (2, 6, 9).

Risk factors for mental ill health include health behaviors such as poor diet quality, physical inactivity, sedentary behavior, alcohol and drug use, smoking, and inadequate sleep quantity and quality (1, 3, 8, 10–13). These health behaviors are associated with mental health when examined as separate risk factors and in combination (14, 15). For example, meta-analyses have inferred smoking as a causal factor in the onset of depression, schizophrenia and bipolar disorder (11, 16), and poor sleep as a causal factor in bipolar disorder and a risk factor for suicidal behavior (11, 17). A significant proportion of university students report health risk behaviors (8, 11). The 2021 National College Health Assessment surveys (n = 96,489) reported that 64% of college students consumed <3 serves of vegetables per day, 58% were not meeting physical activity recommendations, 17% were current smokers, and 41% were not meeting sleep duration recommendations (18). In Australia, data indicate that 54% of students consumed <3 serves of vegetables per day, 29% were not meeting physical activity guidelines, seven percent were current smokers, and 23% were not meeting sleep duration recommendations (3). These poor lifestyle behaviors expose university students to greater risk of mental health disorders and psychological distress (11).

Given the high prevalence of mental ill health and psychological distress (5), and health risk behaviors among university students (8, 11), targeting behavior-change in this population is important, as improvements in health behaviors (e.g., smoking, sleep, alcohol consumption) may mediate improvements in mental health (11, 19). Universities and other tertiary institutions are well positioned to support students to adopt healthier behaviors and have the potential to reach large numbers of students (19–21). A plethora of interventions aimed at improving diet, physical activity, sedentary behavior, alcohol and drug use, smoking, and sleep in university students have been conducted with varying levels of effectiveness reported (19, 21–23). Further, a recent systematic umbrella review located 17 reviews that focused on the effectiveness of interventions to improve university students' mental health (21), but none of these specifically evaluated the effect of health behavior interventions (21). Therefore, while numerous studies have investigated interventions aimed at improving health behaviors in university students, and numerous studies have investigated interventions aimed at improving mental health in university students, to our knowledge no review has been conducted on the extent and range of experimental research that has targeted health behavior change and measured mental health outcomes.

To address this gap in the literature, the aim of this scoping review is to describe the extent and range of randomized controlled trials (RCT) that evaluate interventions targeting health risk behaviors (i.e., dietary intake, physical activity, sedentary behavior, alcohol and drug use, smoking, and sleep) and measure a mental health outcome, among university students.

Of 12,360 articles screened based on their title and abstracts, 315 full-text articles were assessed for eligibility. Sixty-three articles were included in the scoping review (29–89), which reported on 59 RCTs (Figure 1) (29–79, 81–84, 86–89). Of the 252 articles excluded from the scoping review, 20 were excluded as they were not peer-reviewed manuscripts, 25 were not RCTs, four did not include tertiary education students, 34 did not evaluate a relevant health behavior intervention, and 169 did not assess a mental health outcome

Table 1 describes the study characteristics and inclusion criteria of the 59 included RCTs and describes the studies by outcomes measured (i.e., psychological well-being only, mental ill health only, and studies with both psychological well-being and mental ill health as outcomes) (29–79, 81–84, 86–89). Supplementary Table S2 provides full details of the individual RCTs (29–79, 81–84, 86–89).

The year of publication of the included studies ranged from 2000 to 2021, but only one was published prior to 2006 (Figure 2). Many included studies were published between 2012 and 2017 (n = 26, 44.1%) (32, 34, 38, 42, 45, 47–49, 51, 52, 57–59, 64, 65, 67, 69, 71, 73–77, 79, 81, 82). Included studies were conducted in the United States (n = 33, 55.9%) (29, 30, 32, 33, 37, 44, 47–51, 55, 57–61, 63–66, 68, 69, 71, 72, 75, 76, 78, 79, 81, 84, 86, 88), the UK (n = 5, 8.5%), (34, 42, 45, 52, 67) Canada (n = 5, 8.5%) (31, 41, 43, 77, 83), Australia (n = 4, 6.8%) (36, 62, 74, 87), Germany (n = 2, 3.4%) (46, 56), and nine other countries (n = 12, 20.3%).

This scoping review describes the extent and range of RCTs evaluating interventions targeting health behavior change among university students that also measured a mental health-related outcome. The review identified 59 RCTs, with 47 of the RCTs published since 2012. Most interventions focused on a single health behavior, with the three most frequently targeted behaviors including diet, physical activity, and alcohol intake. Of the 41 interventions targeting multiple behaviors, most (n = 27) targeted two behaviors and the most frequent combination was diet and physical activity. The mental health focus varied within the included studies, ranging from treatment to prevention of mental ill-health.

This scoping review highlights that most RCTs in this field to date have focused on interventions targeting diet, physical activity, and alcohol intake-related behavior change, with much less focus on sleep, smoking, drug use and sedentary behavior. Given the high prevalence and co-occurrence of health risk behaviors among university students (8, 11), a more equitable distribution across health behaviors would be expected. However, given this scoping reviews specific focus on RCTs that evaluated a mental health outcome, the greater focus on physical activity interventions is somewhat unsurprising given the strong evidence for the role physical activity plays in both the prevention and clinical treatment of mental ill-health (11, 90). The strong focus on dietary behavior change among studies measuring a mental health outcome however is not as well supported by existing evidence, with less certainty of the causal relationship between diet and mental ill-health (11, 91). Notably, the lower number of included RCTs considering sleep is inconsistent with the growing evidence that poor sleep is a risk factor for poor mental health (11, 92–94).

The current scoping review found most RCTs in this field have focused on changing individual health behaviors to influence mental health outcomes. There is strong evidence of co-occurrence of health risk behaviors in the general population (95–97), and specifically among university students (3, 98–103). Further, there is emerging evidence of the association between co-occurrence of health risk behaviors and mental health (3, 98–100). Therefore, more RCTs evaluating multiple health behavior interventions should be anticipated. However, our findings are consistent with the broader multiple health behavior change field, which highlights limited research considering more than two health behaviors, and a predominant focus on diet and physical activity interventions (104). As previously acknowledged, greater multi-disciplinary research and movement beyond individual health behavior silos is required to advance the multiple health behavior research field overall (105), and this is also true for university student-based research.

This scoping review found that many included RCTs evaluating health behavior change interventions, considered mental health as the primary outcome of the study. In addition, included RCTs focused on mental ill-health and/or psychological well-being related outcomes, and almost one-third of studies had an inclusion criterion that considered the mental health status of participants. Collectively, these findings suggest that RCTs conducted to date have considered health behavior change interventions as a strategy for treatment and prevention of mental ill-health, along with mental health promotion. Notably though, a large number of studies (n = 151) were excluded from the review as they met all other inclusion criteria except for the requirement to assess a mental health outcome. This emphasizes that despite the evidence of poor mental health among university students, and the association between health behaviors and mental health, many RCTs evaluating health behavior change interventions in this setting have not considered the impact on student's mental health.

Notably, many of the included RCTs limited participants to the young adult population, and often to specific student sub-groups, including first year students/freshman. This focus was supported by the evidence of the transition from school to tertiary education having a negative influence on health behaviors, as well as mental health. Further, many (56%) of the included studies were conducted in the United States, with only a small number (≤ 5) conducted in each of the other countries. Therefore, whilst the results confirm some homogeneity within the available evidence-base, the applicability of the evidence to other student sub-groups (e.g., older students, post-graduate students), and outside the United States, may be limited.

This scoping review has several strengths. It is the first scoping review to comprehensively examine RCTs undertaken to evaluate heath behavior change interventions among university students, with a specific focus on those that measured mental health outcomes. The conduct of the scoping review was consistent with PRISMA-ScR (24), and as such employed a comprehensive search strategy across numerous databases. The study was limited to studies published in English, and therefore may not include all published RCTs. Notably, the review focused on RCTs, as the highest level of evidence from experimental study designs. However, this does mean that other experimental study designs (e.g., non-randomized trials) were excluded from the review. In addition, as is convention for a scoping review the review only considered the extent and range of studies; therefore it did not explore the efficacy of the interventions. Further, the review also did not consider the methodological quality of the included RCTs.

There is a moderate volume of research exploring the impact of health behavior interventions for university students on mental health outcomes. Of note, the RCTs included in this scoping review can be utilized as a foundation to conduct a systematic review. There is scope for such a systematic review to be limited to specific health behaviors (e.g., diet, physical activity or alcohol intake) or mental health outcomes (e.g., mental ill health or psychological well-being), based on the higher number of included studies. Such a review would help inform the implementation of health behavior interventions in the university setting. Finally, future RCTs examining health behavior interventions targeting university students should: consider less evaluated health behaviors, such as sleep; consider targeting multiple health behaviors within the one intervention approach; and assess mental health as a primary or secondary study outcome.

The original contributions presented in the study are included in the article/Supplementary material, further inquiries can be directed to the corresponding author.

MH: conceptualization, methodology, investigation, writing–original draft, supervision, project administration, and funding acquisition. MW: conceptualization, methodology, investigation, writing–review and editing, supervision, and funding acquisition. NY: methodology, investigation, visualization, writing–review and editing. SF: investigation, visualization, and writing–original draft. MD, FK-L, and TB: conceptualization, methodology, writing-review and editing, and funding acquisition. All authors contributed to the article and approved the submitted version.