Although the drug use pattern among medical students shows an alarming increase, the average drug use is still significantly lower in this particular population than average national reports in Iran[23]. Tehran University students are part of the elite group of young people. This result shows drug use has become more prevalent among them, which may indicate a more significant rise among the students of other universities since they might face less social restriction than medical students.
Surveys measuring the prevalence of drug use among students are important studies since the students’ sample is relatively homogenous and collected from a standard group, making it possible to generalize data to larger populations with similar features. University surveys are inexpensive, easy to administer, and yield high-quality data; these characteristics make the school surveys the best method of collecting data on substance use in the youth population[24]. Several surveys are conducted annually on students in Europe and the USA, which helps them have a better picture of what is happening concerning drug use among students by using the comparable data that can determine a pattern of use over the years[25, 26]. However, since the initiation age of drug use is slightly higher in Iran, students studies are not practical; as a result, most of the studies are conducted on university students. This may be because high school students in Iran do not have that much liberty compared to their American and European counterparts. Moreover, students, mainly medical students, form the country's future human capital and human resources; as a result, this rise in the pattern of drug use can have detrimental financial and social outcomes for the country[8]. Many studies state that since starting the university highlights a transformative time in life and is the start of independent life, and many habits are established in this period, it is the best time to evaluate the prevalence of drug use and implement preventive measures. In addition, the initiation of substance use usually occurs at this timeline[7, 8, 23, 27, 28]
According to our study, 10.5% of medical sciences students reported lifetime use of any drug. In the past year and the past month, any drug use was 6.6% and 4.2%, respectively. These results showed that drug use has become more prevalent in this group two times compared with the similar study conducted a decade ago[20]. However, this figure was significantly lower than those in western countries like the USA and Spain, where the history of drug use in the past 12 months was around 45% in the young population[8, 29]. Other countries like Sudan and Lebanon reported only slightly higher figures for any drug use[30, 31].
The observed increase in drug use is mainly attributable to the rise in cannabis and methylphenidate users. On the other hand, the percentage of opioid users has dropped around five times[20]. Although cannabis use is rising among students in Iran, it is still eight times less prevalent than similar surveys in the USA; however, in the case of prescribed amphetamine products, they reported almost similar results as this survey[8].
Cannabis was the most commonly used illicit drug, reported by 4.9% and 2.6% of the students in the past 12 months and last month, respectively. These results are significantly lower than the one conducted in the USA, which estimated the past twelve months use of cannabis was about 41% and last month use was about 24% among college students[8]. A study on Spanish students reported a high prevalence of cannabis use in the past 12 months, almost ten times higher than our study[29]. However, Another study in Sudan reported 7.1% in the last 12 months of cannabis use in students, figures which are more similar to our result[31]. A systematic review article established 17.2% of students have a history of past 12 months of cannabis use[32].
In many countries across the globe, cannabis is the main illicit drug used by university students [8, 29, 31, 33]. In Iran, opioids and mainly opium were traditionally the most commonly used drug in the general population and among university students up to the past decade. During the late 2000s and 2010s, we are facing an increase in the use of cannabis and a decrease in the use of opioids among university students in Iran[20, 34–37].
In our study, 1.5% reported they had used opioids in the past 12 months and 0.4% in the past month. The main opioid used was opium, and only 0.2% reported heroin use in the past 12 months. The decreasing trend in the use of opioids can be attributed to the change in the attitudes of the young generation toward opioids and considering opium as old-fashioned, increased awareness of the risks of opioid use, and the increasing popularity of cannabis among the younger population[9, 38]. The prevalence of heroin use in Iranian students is equivalent to their American counterparts[8]. The study on Sudanian students reported the same prevalence of opiate use in the past 12 months as our study[31]. Lebanese students reported 4% of opioid use in their lives, which was twice as high compared to our study[30].
The use of methylphenidate in the last 12 months was reported by 2.9% of the students, the second most commonly used drug following cannabis. The rate of methylphenidate use was about two times higher than a similar previous study[20]. A study conducted on Belgian students reported figures twice as high as ours. Another study in Pakistan reported about 6% methylphenidate use among medical students[39].
Drug use was more prevalent in the male gender, similar to almost all previous studies. In the bivariate analysis, being a male revealed three times higher odds of using drugs. However, the multivariate analysis showed that it was not a determinant factor. Studies suggest that a higher prevalence of drug use among the male gender can be attributed to fewer social restrictions concerning males and more opportunities for use. However, in a similar situation, women might be as susceptible to using drugs as men[40, 41].
Our result indicated that almost one-third of cigarette smokers had a history of drug use in the past year, which was the most influencing risk factor. A Study showed the probability of heroin use is six times higher in cigarette smokers and somewhat similar rates in the crack, cocaine, cannabis, and MDMA use[1]. Moreover, the average starting age of smoking was lower than other drugs. Smoking cigarettes is considered a gateway in other studies[42].Since 1970, many studies have suggested that smoking cigarettes may facilitate using other drugs. Many adolescents who smoke find it easier to use drugs since they find themselves more rebellious and do not fear the social stigma of drug use[43, 44]. Even though the world pattern has changed and new studies showed that cannabis has become the gateway for other drugs in the young population, cigarettes are still the main gateway in Iran.
Consuming alcohol was a significant predisposing factor in our study, consistent with several other former studies suggesting that using one substance provides the setting for easier access and use of the other substances. Many suggest that people who consume more alcohol usually struggle with more problems in their personal life, which propel them to use other drugs[45, 46].
Our study showed male and female students having a family member or close friends who used drugs are more prone to drug use. Over the years, studies have shown various environmental factors based on behavioral learning models for drug use. Drug use in family or close friends provides more access and opportunity to use drugs and establishes a positive or normative attitude towards drugs[47, 48].
There was an association between drug use and gambling and betting in the past year; previous studies have suggested that gamblers are more disposed to dangerous behaviors such as drug use since they have more difficulty controlling their impulses[49, 50].
4% of the students perceived occasional use of opium imposes no risk for their health, 33% perceived medium risk, and 61% perceived high risk concerning occasional use of opium. The figures for cannabis were 3%,17%, and 78%, respectively. Contrary to this result American students reported a more positive attitude toward cannabis with only 24% considering its ocasional use as a high risk behaviour[8]. This trend can be attributed to the popularity of cannabis among young population and legalisation of cannabis use in some countries[6, 51].
Strengths and limitations
Strengths of the study include having a representative sample of TUMS students, a relatively high response rate, low missing data. Although only 10 percent of the students refused to fill out the questionnaire, there is a probability that this group had a higher prevalence of substance use, thus leading to non-response bias. Students who skipped classes during the fieldwork may further contribute to this bias. We may have underestimated the results. Moreover, despite the anonymity of the questionnaires and reassuring participants on confidentiality, some may have under-reported their use. These limitations are also applicable to other similar drug surveys and explain the possibility of under-reporting.