Alcohol is a psychoactive and addictive substance and remains a major public health concern worldwide (1). According to the World Health Organization’s 2019 report, harmful use of alcohol is responsible for approximately 3 million deaths annually, accounting for 5.3% of all global deaths. Moreover, alcohol consumption contributes to 5.1% of the global burden of disease and injury, equaling 132.6 million years of healthy life lost (DALYs). The global average per capita alcohol consumption among individuals aged 15 and older is estimated at 6.4 liters per year, with a general prevalence rate of around 43% (2).

Despite legal prohibitions and strong cultural norms in Iran, recent evidence suggests a growing trend of alcohol consumption among youth and university students (3, 4). A study conducted during the 2017–2018 academic year on 450 students from various universities in Urmia reported an alcohol use prevalence of 15.82% (5). Additionally, a 2019 systematic review and meta-analysis of Iranian studies estimated that about 15% of young people had consumed alcohol (6). Another study in 2022 among students at Bojnourd University of Medical Sciences found that 7% had consumed alcohol within the past year (7). These findings indicate that, despite legal and religious restrictions, alcohol consumption is relatively prevalent among Iranian youth (6).

In addition to its addictive properties, alcohol has extensive negative effects on individual and public health. It is widely regarded as a chronic, progressive, and potentially fatal disease (8). Recent studies show that alcohol's net health impact is entirely negative and that the only safe level of consumption is none at all (9). Alcohol use can harm multiple systems in the body, leading to liver conditions such as fatty liver and cirrhosis, cardiovascular disorders, neurological damage, cognitive impairments, several types of cancer, infections, hormonal imbalances, diabetes, and diseases of the bones, kidneys, blood, and muscles (2, 10, 11). From a psychological perspective, alcohol use can cause mental health disorders, addiction, depression, anxiety, and specific syndromes like Wernicke–Korsakoff (12). It may also impair students’ academic performance (13). Nevertheless, in some subcultures, drinking alcohol is viewed as a symbol of modernity and social prestige, particularly among youth and students (14, 15).

Globally, preventing alcohol use remains a critical priority in public health agendas (16). Identifying the factors that influence preventive behaviors—especially among young adults—is therefore essential (17). In this context, behavioral health theories offer a valuable framework for understanding and promoting such behaviors (18). One of the most widely applied models is the Theory of Planned Behavior (TPB), introduced by Ajzen in 1991, which is frequently used to analyze health-related and substance use behaviors, including alcohol consumption (19, 20). According to this theory, the strongest predictor of behavior is behavioral intention, which is influenced by three main constructs: attitude toward the behavior, subjective norms, and perceived behavioral control (19). Numerous international studies have confirmed the effectiveness of this model in predicting alcohol-related preventive behaviors among university students (21).

Given the rising prevalence of alcohol consumption among students, the importance of preventive interventions in this population, and the limited number of Iranian studies applying the TPB to alcohol use—most domestic research has focused instead on behaviors such as risky sexual activity (22), cigarette smoking (23), and drug use (24)—this study aimed to examine preventive behaviors related to alcohol consumption among students of the School of Paramedical Sciences and Public Health at Islamic Azad University of Mashhad, based on the Theory of Planned Behavior.

The study population consisted of students from the School of Allied Medical Sciences and the School of Public Health at Islamic Azad University, Mashhad Branch. The minimum required sample size was initially estimated to be 332 participants based on a previous study by Hamidian Rad et al. (25), which reported an alcohol consumption prevalence of 15.82%, with a 5% Type I error and 4% precision, using the following formula:

However, due to the lack of similar studies in Mashhad, a conservative prevalence of 50% was assumed. Accordingly, the required sample size was calculated to be 386. Accounting for a 20% potential dropout rate, the final sample size was set at 420 participants.

A convenience sampling method was employed. Following the approval of the study by the Vice-Chancellor for Research at Mashhad University of Medical Sciences and obtaining the necessary permissions, initial coordination was made with the heads of the relevant faculties. The researcher then attended classrooms in person, explained the study’s objectives, and invited eligible and willing students to participate. Of the students approached, 429 completed the questionnaire. After excluding 7 incomplete responses, data from 422 participants were included in the final analysis. The self-administered questionnaires were completed in-class within approximately 30 minutes, with the assistance of faculty officials and the presence of the researcher.

Inclusion criteria included Iranian nationality, willingness to participate, and current enrollment in one of the two relevant faculties at Islamic Azad University, Mashhad. The exclusion criterion was failure to complete the questionnaire.

Two instruments were used for data collection. Demographic Questionnaire: This section gathered demographic and background information including age, gender, field and year of study, marital status, place of residence, parents’ education and occupation, family income, personal alcohol use, alcohol use among relatives, having friends who consume alcohol, and history of emotional or psychological problems.

Preventive Behavior Questionnaire (Based on TPB): To assess preventive behaviors regarding alcohol use, a researcher-made instrument based on the Theory of Planned Behavior (TPB) was utilized. The questionnaire was developed with reference to credible sources and the core constructs of the TPB. To ensure face and content validity, the initial version was reviewed by 12 experts in health education and health promotion, and their feedback was incorporated. Quantitative content validity was assessed using the Content Validity Ratio (CVR) and Content Validity Index (CVI), which were found to be 0.81 and 0.97, respectively — indicating strong content validity.

To assess reliability, the questionnaire was administered to 20 individuals from the target population (excluding those in the main study), and re-administered after 10 days. Test–retest reliability was evaluated using Intraclass Correlation Coefficient (ICC), and internal consistency was assessed using Cronbach’s alpha. ICC values were as follows: attitude (0.94), subjective norms (0.90), perceived behavioral control (0.79), behavioral intention (0.89), and preventive behavior (0.87). Cronbach’s alpha values were: attitude (0.82), subjective norms (0.72), perceived behavioral control (0.70), behavioral intention (0.72), and preventive behavior (0.75) — all indicating satisfactory reliability.

The final questionnaire consisted of 23 items covering the five TPB constructs: Attitude (8 items, score range: 8–40): Focused on negative attitudes toward alcohol consumption; higher scores indicated more negative attitudes. Subjective Norms (4 items, score range: 4–20): Measured the influence of social norms promoting alcohol avoidance. Perceived Behavioral Control (4 items, score range: 4–20): Assessed perceived control over avoiding alcohol use; higher scores reflected stronger self-control. Behavioral Intention (3 items, score range: 3–15): Evaluated intentions to adopt preventive behaviors; higher scores indicated stronger intentions. Preventive Behavior (4 items, score range: 4–20): Assessed actual preventive behaviors regarding alcohol consumption. Items related to attitude, subjective norms, perceived behavioral control, and intention were rated on a 5-point Likert scale from "Strongly disagree" (1) to "Strongly agree" (5). Reverse-coded items were scored accordingly. Preventive behaviors were rated on a 5-point frequency scale from "Never" (1) to "Always" (5).

The English version of this researcher-developed questionnaire is available as a supplementary file for this article.

A total of 422 questionnaires were completed and analyzed by students from the School of Paramedical Sciences and Public Health at Islamic Azad University of Mashhad. According to the findings in Table 1, the majority of participants were female students. In terms of academic major, laboratory sciences students made up the largest proportion. Most of the participants’ parents had educational levels above a high school diploma. Regarding occupation, self-employment was the most common among fathers, while homemaking was most common among mothers. Additionally, most participants reported a moderate economic status.

In terms of alcohol consumption patterns, the majority of participants were non-users of alcohol and reported no history of alcohol use among their close relatives or friends. However, a percentage of participants reported either personal use or exposure to alcohol use in their social circles. Some individuals also reported a history of psychological or emotional issues.

Based on the results shown in Table 2, several demographic variables were significantly associated with preventive behavior scores related to alcohol consumption. The mean preventive behavior score was significantly higher among female students compared to males (P < 0.001). Students majoring in public health and surgical technology had significantly higher preventive behavior scores compared to those in other fields (P < 0.001). Married individuals demonstrated significantly higher levels of preventive behavior than single students (P = 0.012). Place of residence also showed a significant relationship: students living with their parents or spouse scored higher than those living alone or with friends (P = 0.002). Mother’s education level was significantly associated with preventive behavior scores, with the highest mean scores observed among students whose mothers had a high school diploma (P = 0.026). Mother’s occupation was also influential; students whose mothers were homemakers demonstrated better preventive behavior (P = 0.026). There was a statistically significant relationship between preventive behavior scores and alcohol use among relatives: the highest scores were observed in students with no relatives who consumed alcohol, while the lowest scores were among those with both close and distant relatives who consumed alcohol (P < 0.001). A significant relationship was also found between alcohol consumption by close friends and preventive behavior scores: students whose close friends did not consume alcohol had higher preventive scores (P < 0.001). Moreover, there was a positive and significant correlation between the age of alcohol use initiation and preventive behavior scores—meaning that the later the initiation age, the higher the preventive behavior score (P = 0.043).

Table 3 presents the frequency distribution of scores related to the Theory of Planned Behavior (TPB) constructs and alcohol-related preventive behaviors. The results indicate that participants scored highest in the constructs of attitude and perceived behavioral control, while the lowest scores were observed in behavioral intention and subjective norms. The mean preventive behavior score across all participants was 17.12 (SD = 3.54) out of a maximum score of 20, indicating that participants achieved approximately 85.6% of the total possible score.

As shown in Table 4, there were statistically significant and positive correlations between all TPB constructs and alcohol-related preventive behaviors (P < 0.001). The strongest correlation was observed between behavioral intention and preventive behaviors, followed by attitude, subjective norms, and perceived behavioral control.

The present study aimed to identify preventive behaviors related to alcohol consumption among students of the Faculty of Paramedicine and Health at Islamic Azad University of Mashhad, based on the Theory of Planned Behavior (TPB). The findings revealed statistically significant relationships between preventive behaviors and the constructs of TPB, including attitude, subjective norms, perceived behavioral control, and behavioral intention. The strongest correlation was found between behavioral intention and preventive behaviors, followed by attitude, subjective norms, and perceived behavioral control, respectively. These findings align with the results of the study by Delpia et al. (26), which examined preventive behaviors regarding alcohol and tobacco use among students in West Kalimantan. They also reported that the four main constructs of the TPB significantly influenced preventive behaviors, with behavioral intention being the strongest predictor.

Similarly, Mobasheri et al. (27) found that intention was the most significant predictor of behavior, underscoring the importance of fostering healthy behavioral intentions in reducing high-risk behaviors. The present findings are also consistent with the study by Tavakoli Ghoochani et al. (24), which was conducted among students at North Khorasan University of Medical Sciences. That descriptive study found significant associations between behavioral intention and the TPB constructs of attitude, subjective norms, and perceived behavioral control. Among these constructs, attitude toward substance use was identified as the strongest predictor of behavioral intention. This convergence in results highlights the critical role of personal attitudes toward the consequences of behavior in shaping intentions and ultimately engaging in or avoiding risky behaviors.

In the present study, 17.3% of students reported alcohol use, with a mean age of initiation at 18.22 ± 2.13 years. These results are consistent with those of Mozaffari-Nia et al. (28), conducted at Tehran University of Medical Sciences, where 19.9% of students had consumed alcohol at least once in their lifetime, with an average initiation age of 18.6 years. However, the slightly lower prevalence reported in the current study may be attributed to several factors, such as cultural and religious differences between Mashhad and Tehran, as well as variations in data collection methods and participants’ honesty in responding. This underscores the importance of considering cultural and social contexts in the design and implementation of preventive programs.

The findings also showed that the mean score of preventive behaviors was significantly higher among female students compared to males. This is in line with the results of Yıldırım and Özaslan (29), who, during the COVID-19 pandemic, found that women were more likely than men to engage in protective behaviors, including adherence to health guidelines and avoiding public gatherings. Similarly, a report by the National Institute on Drug Abuse (NIDA) (30) indicates that men in most age groups are more likely than women to consume alcohol and face a higher risk of alcohol-related disorders. Although the gender gap in alcohol consumption has been narrowing in recent years—especially among younger generations—women remain biologically more sensitive to the harmful effects of alcohol and are at greater risk of severe health consequences (31).

This study also found that married individuals demonstrated more preventive behavior against alcohol use. This finding corresponds with the results of Pollitt et al. (32), who found that married couples consumed less alcohol and exhibited lower rates of alcohol use disorder compared to single individuals, a pattern attributed to social control norms and mutual monitoring within marital relationships. However, a study involving monozygotic and dizygotic twin pairs revealed that under certain conditions, married men might consume more alcohol than their single counterparts, indicating the complex and multifaceted influence of marriage on consumption behaviors (33). Furthermore, the present study indicated that students living with their parents or spouse displayed more preventive behaviors compared to those living alone or with friends. Similar findings were reported by Pape et al. (34), who observed that single individuals or those living with peers were more frequently exposed to environments where alcohol consumption is normalized or even encouraged.

The study also found that students whose mothers were homemakers exhibited better preventive behavior toward alcohol consumption. This is consistent with the results of Mobasheri et al. (27), who also reported that having a homemaker mother had a positive impact on reducing both the intention and behavior related to alcohol use, with this effect being stronger than that of working mothers. Other studies have emphasized that homemaker mothers, due to having more time to monitor and establish effective emotional connections with their children, play a significant role in reducing high-risk behaviors such as alcohol, tobacco, and drug use (35–37).

In this study, alcohol consumption by close and distant relatives was significantly associated with students’ preventive behavior scores. Students whose relatives did not consume alcohol had the highest preventive behavior scores, while those with both close and distant relatives who drank had the lowest. This finding highlights the negative impact of familial alcohol use patterns on preventive behaviors. Ólafsdóttir and Marinósson (38) reported similar results, showing that individuals who lived with alcohol-using relatives during childhood were more likely to consume alcohol in adulthood. Additionally, Stephenson et al. (39) emphasized that parental alcohol use is associated with earlier and more intense alcohol consumption in their children. These findings underline the importance of family role models and subjective norms as key factors in shaping preventive behaviors or tendencies toward risky behaviors.

Finally, the results showed that students whose close friends did not consume alcohol had higher scores in preventive behaviors. This finding is consistent with the study by Bazazian et al. (40), which demonstrated that peer alcohol use was significantly and positively associated with students' inclination to drink. Within the framework of the Theory of Planned Behavior, these findings highlight the critical role of subjective norms in influencing preventive behaviors.

This study has several limitations that should be considered when interpreting the findings. Firstly, the data were collected using self-reported questionnaires, which may introduce response bias, particularly given the sensitive nature of alcohol consumption. Secondly, the sample was limited to students from the School of Paramedical Sciences and Health at Mashhad Azad University, which restricts the generalizability of the results to other student populations or age groups. Additionally, the cross-sectional design of the study does not allow for the assessment of behavioral changes over time or the long-term effects of preventive factors. Finally, certain cultural, social, and psychological variables influencing alcohol consumption behavior—such as religious beliefs, family pressures, and media influence—were not examined in this study.

Based on the limitations noted, future research should consider expanding the sampling frame to include a more diverse range of universities and demographic groups to enhance the generalizability of the findings. Employing mixed-method approaches, including in-depth interviews and focus groups, could provide a more comprehensive understanding of the factors influencing preventive behaviors. Designing and implementing educational interventions grounded in the Theory of Planned Behavior, with an emphasis on strengthening positive attitudes, modifying subjective norms, and increasing perceived behavioral control, may effectively reduce high-risk behaviors. Furthermore, addressing the roles of family and peers through peer-pressure coping skills programs is recommended. Finally, longitudinal studies are encouraged to evaluate behavioral changes over time and the effectiveness of interventions.

The findings of this study revealed that despite legal prohibitions and cultural restrictions, alcohol consumption exists among a portion of students at the School of Paramedical Sciences and Health, Mashhad Azad University. The study also demonstrated that preventive behaviors against alcohol consumption are associated with certain demographic characteristics, including gender, field of study, marital status, and living conditions. Notably, female students, married individuals, and those living with their parents scored higher on preventive behaviors.

According to the Theory of Planned Behavior (TPB), preventive behaviors were significantly correlated with negative attitudes toward alcohol consumption, supportive subjective norms for prevention, high perceived behavioral control, and a strong intention not to consume alcohol. These findings confirm that TPB provides a suitable framework for designing educational and behavior change interventions in this context.

Therefore, given the effectiveness of TPB components in explaining preventive behaviors related to alcohol use, it is recommended that university educational programs focus on enhancing negative attitudes toward alcohol consumption, strengthening social norms that support abstinence, and increasing students’ self-efficacy to resist social pressures. Such interventions could play a crucial role in reducing the inclination to consume alcohol among students and contribute to the improvement of their physical, psychological, and social health.