In this study, 1183 Egyptian university students were surveyed. The prevalence of substance use was 6.5% and the prevalence of dependence was 0.5%. The study revealed a high significance association of substance use to the field of study. The prevalence of substance use in students enrolled in practical educational programs was twofold higher than in medical or theoretical students. Practical students also showed the highest rate of drug dependence. Male sex, age ≥ 20 years, smoking, and urban living have been identified as independent risk factors of substance use among Egyptian university students.
In the current study, 10.3% of male students utilized substances, whereas only 1.4% of female students did. This finding is in line with the findings of a recent national study in Egypt, which demonstrated that 15.8% of males and 2.2% of females from various professions have used substances at least once in their lives . This finding is also consistent with other studies [7, 9, 11, 26,27,28]. This low prevalence of substance use among female individuals of Egyptian university students could be due to social stigma, which may cause them to deny substance use, or it could be due to the higher social tolerability of substance use among males .
Another interesting finding in our study was that 22.5% of the participant students were smokers. This is consistent with a study conducted in the USA in which smokers were less than 20%  and in North Carolina and Virginia smokers were 50% . Approximately, the same was found in other studies as [1, 7, 13, 31, 32].
Looking to cigarette smoking as a major factor associated with substance use, our study found that 83.8% of substance users are smokers and this is consistent with studies as [7, 9, 33, 34]. The high prevalence of smoking among substance users may refer to smoking as a predictor of substance use besides the easy accessibility and legalized use of smoking.
Utilizing substances is one of the most devastating public health issues especially among university students as they are a highly vulnerable group for this problem. In this study, the prevalence of substance use was 6.5%, which is by a study conducted in Turkey where the prevalence was 6.3% , and slightly higher than the prevalence of 5% among a similar population in Egypt . However, much higher rates were reported in other studies such as 28.6% in Ethiopia, 3542.8% among health care students in Nepal , and 69.8% in Kenya .
This low prevalence in our study might be due to different sampling techniques or due to cultural and societal differences.
Cannabis is the most commonly used substance by about 24.3% of the participant users followed by tramadol, alcohol, benzodiazepines, and heroin with the percentage of 8.9%, 13.5%, 6.8%, and 1.4% respectively. This is in agreement with other studies performed in Egypt, Sudan, and Kuwait [7,8,9].
This pattern is also consistent with the latest Egyptian national survey, where the most misused substance was cannabis (77%) . The increased prevalence of cannabis use could be linked to a recent decline in public awareness of the risk associated with its use. Several researchers have found that a low-risk perception is linked to a higher likelihood of drug usage [37,38,39,40]. Tramadol came second as the most consumed substance after cannabis in our participants and has become a public health issue in Egypt. Numerous research looked at its widespread use among adolescents , and its ramifications among substance use patients .
Among all students in our study, 10.7% of practical students and 5.5% and 5.2% of medical and theoretical students, respectively, have been identified as substance users. In the study performed by Bassiony and colleagues in 2018, the percentages of substance use among practical and theoretical colleges were 11.8% and 43%, respectively . In another study published in the same year by the same group, the percentage was 34.1% among practical and 65.9% among theoretical students .
Regarding the most used substances in each category, tramadol is the most commonly used substance among medical students (1.8%), cannabis and tramadol came on top with the same percentage (2.3%) among practical students. Among theoretical college students, cannabis was the most used substance (1.8%). On the other hand, in a study done among Zagazig University students, the most used substances among practical students (including medical) were alcohol, tramadol , and in another study in the UK, cannabis came on top among medical students .
Tramadol is used as an analgesic for both acute and chronic pain and arbitrates analgesia as an opioid receptor agonist and synergistically as a serotonin-norepinephrine reuptake inhibitor . In Egypt, there is a misconception that opioids enhance cognitive and sexual performances and delay physical exhaustion . This could explain that medical and practical students mainly use substances to cope with the study stress or to get more power to enhance their physical and mental performance.
Practical students had the highest dependence percent (10.7%) in the current study. While medical students had the highest rate of drug-related problems (83.3%), Bajwa and colleagues  reported the highest percentage of drug-related problems to be among practical students as medical students counted as practical while the highest percentage of dependence was found among theoretical students. On the other hand, Bassiony and colleagues  found the highest drug-related problem percentage among theoretical students. The knowledge of medical students about the hazards of substance use and its devastating effect on health could be the cause of their low percentage of dependence.
Educational and preventive programs should be established as early as possible for high school students to increase their orientation regarding substance use and its estimated hazardous effects. Rehabilitation programs should be applied to students who have problems with substance use to minimize consequences.