This study examined awareness and attitudes related to NPS as well as the prevalence and predictors of this behavior among future HCPs in Serbia. The socio-demographic and academic characteristics of students as well as their habits regarding (il)licit psychoactive substances (ab)use were evaluated as the main correlates of NPS awareness and use in this study group consisting of 490 future Serbian HCPs.

Even though half of the respondents (54.29%) were tobacco consumers and almost all (95.31%) drank alcohol beverages, such habits could not be used as a predictor of NPS awareness among Serbian future HCPs (IRR = 1.038, CI = 0.659–1.633, p = 0.873 and IRR = 1.087, CI = 0.515–2.295, p = 0.828, respectively). On the contrary, in the most recent study investigating knowledge and perceptions of synthetic cannabinoids among university students in Jordan, the authors reported that being a smoker (aOR = 1.369, 95% Cl = 11.041–1.871, p = 0.026) as well as an alcohol user (aOR = 2.134, 95% CI = 1.362–3.346, p = 0.001) were predictors of good knowledge [13].

The lifetime use of cannabis was reported by 24.49% of the respondents in our study, which is in agreement with the earlier study conducted in Belgrade, Serbia, among medical students (34.9%) [21], as well as with the study including prospective doctors at the University of Novi Sad (33.2%) [17]. According to Shafiq et al., 78% of the medical students had no intention of ever using a drug and a predominant anti-drug opinion was noted among them [22]. In the study by Khalid et al., 82.7% participants did not justify hashish use under any circumstances and 88.2% of them were medical students [23]. It would be extremely important to obtain data regarding the motivation for starting the consumption of psychoactive substances. The self-medication often lies behind substance abuse. This opens new professional questions on the topic of students’ mental health and the need for early recognition and interventions in this vulnerable category.

Paut-Kusturica et al. also determined that students’ knowledge regarding medical cannabis was in strong correlation with previous marijuana consumption, as previous marijuana users were more knowledgeable about therapeutic and side effects, while students who never consumed marijuana were more aware of possible abuse [17]. Similarly, previous habits regarding marijuana consumption were predictors of NPS awareness in our study—students who had tried/used marijuana knew 52.6% more NPS names than those who had never had experience with cannabis (IRR: 1.526, CI: 0.953–2.445, p = 0.049).

Although the majority of students were female, the frequency of previous cannabis use was significantly higher among male students. This finding is compatible with those obtained in the recent study reflecting the medical students’ knowledge regarding medical cannabis use in Serbia [17] but not with the results by Moeller et al., where no gender differences was noticed regarding previous marijuana consumption among pharmacy students [24]. One of the reasons for male predomination might be, as well, a greater propensity of the males for psychoactive substances (including NPS), which has been noted in numerous publications [25,26,27,28,29]. Being male is also responsible for better NPS awareness in our study—female students knew 36.5% less NPS names than their male colleagues (IRR: 0.635, CI: 0.399–1.013, p = 0.049). Moreover, this gender distribution can be explained by the lower willingness of men to seek help in case of mental problems and the potential search for self-medication through substance abuse, unlike women, who are more willing to seek help by talking to professionals.

In the present survey, number of NPS names students know was rising 15.9% with each study year—the higher the age, the larger the number of NPS they were aware of (IRR: 1.159, CI: 1.025–1.310, p = 0.018). This is in accordance with results by other authors worldwide. Assaf et al. reported that second-year students had significantly lower knowledge regarding psychoactive substances than third- (p = 0.004) and fourth-year students (p < 0.001), with the differences being in the knowledge of the classification of some drugs, dependence criteria, and alcohol withdrawal [14]. Additionally, Cape et al. reported a significant increase in knowledge scores from 23.4% in the second year to 71.8% in the final year of medical education [30]. In the study by Haddad et al., a comparison was made between grade 10 and 11 high school students, where older students reported more awareness towards substance abuse [31]. Moreover, a total of 33% rated their knowledge of substance use as “very good” and most of these were students in the higher grade. Similarly, in the study by Shafiq et al., seniors (fourth- and fifth-year students) reported fewer benefits of substance use compared to juniors (first, second, and third-year students) [22].

NPS awareness in our study was better in pharmacy students (IRR: 1.926, CI: 1.173–3.163, p = 0.010) than in medicine students—in other words, pharmacy students knew 92.6% more NPS names than their peers studying medicine. This finding might imply that students who had additional (extra) pharmacology and toxicology classes, like pharmacy students in Serbia, gained better knowledge of NPS. Even though medical students attend psychiatry lessons as well as emergency medicine clinical practice during their fifth and sixth years of studies, they were not singled out regarding their knowledge about the topic. Moreover, only 1.62% respondents from our study mentioned practical (clinical) lectures as sources of information regarding NPSs, whereas theoretical lectures were underlined by 23.79% of the participants. One third of the sample (34%) advised improvements in education in schools and faculties about NPSs as main protective measures against NPS use in vulnerable populations. It also should be emphasized that participants of our study were mostly uncertain regarding all the offered claims about NPS.

In the study evaluating awareness of last grade medical students of the danger of synthetic cannabinoids [15], the internet (including social media) (48.6%) and pharmacology lectures (40.5%) were identified as the most stated sources of information about NPS. In the same study, students with social media accounts had significantly higher NPS awareness scores (p < 0.05) [15]. On the other hand, our results have shown that social media account existence did not affect students’ knowledge about NPSs. Additionally, our findings that parents’ professional qualifications as well as a source of income were not predictors of the students’ awareness of NPSs are not in line with a broader literature indicating that some forms of substance use as well as patterns of such use are more common among students whose parents have university education. The authors agreed that many NPSs are currently “legal” and available for purchase in convenient stores and on the internet, making them easily accessible for young adults, especially those with economic means to purchase [32,33,34]. Even though most of the participants in our study lived in urban areas, residence did not affect students’ awareness of NPS, which is not comparable with the previously published data by Martinotti et al. (2015)—more knowledge of NPS was registered among adolescents in urban areas [20].

The present findings indicate that although almost one third of the sample had heard of NPSs and 5.10% reported being offered NPSs, use among students was very low (0.41%). In the study assessing diffusion, knowledge, and risk awareness of NPS among UK students, 81.8% of the student sample had heard of a substance “referred to as a ‘legal high’“ and 31.4% confirmed having used “legal highs” at least once in their life [35]. However, the sensitive nature of asking respondents about previous use of NPSs could be a reason for misreporting on this topic in our study. While students from the UK emphasized first of all the “enjoyable effects” (55.7%) and the “easy availability” (45.70%) of these substances [35], future HCPs in our study reported taking NPSs to improve concentration and learning ability. Only for 15.7% of respondents from the UK could it be speculated that they had taken NPS due to their different/non-recreational nature such as cognitive enhancers, sleeping pills, and drugs to reduce body weight and/or to enhance sexual performances [35]. The potential of substances to induce psychological disturbance should be considered as well. This could lead to serious consequences for the mental health of young people.

The most commonly marked NPS names were Vanilla Sky (methylenedioxypyrovalerone), mephedrone, and Meow-Meow (mephedrone), recognized by 34.8%, 24.3%, and 19.1% of the participants, respectively. These products, together with synthetic cannabinoids, are available over one decade at the Serbian NPS market and their appearance can be traced back to 2010–2011 [5], so that could be a reason for better students’ awareness.