Internet Addiction and Sleep Disorders among Medical Students

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Background
In recent years, the Internet has explosively grown and transformed the world.Better opportunities for education, communication, banking, business, health seeking, and social interaction have been provided through the Internet [1].Iran has also experienced a huge rise in Internet usage, with young people making up the majority of users [2].Internet usage has its pros and cons as well.On the one hand, it can be useful and efective; on the contrary, it can be harmful and cause mental health problems [3].
Yang coined the phrase "Internet addiction," which has since attracted the attention of psychologists, psychiatrists, therapists, scientists, and especially Internet users [4].Internet addiction is defned as excessive or uncontrolled preoccupations, urges, or behaviors regarding utilizing and accessing the Internet that might result in a disorder [5].Increased use of digital media and the Internet mildly afects people's sleep habits, and with changes in sleep quality, symptoms of depression, anxiety, and stress are exacerbated [6].Internet addiction is efective on the quality and quantity of sleep of medical students, especially in men, due to more use of social networks, and it leads to their daily dysfunction [7].Also, this addiction is associated with signs of social exclusion and other prevalent psychiatric problems such as mood disorders, anxiety, poor impulse control, and substance abuse [5].Te prevalence of Internet addiction varies around the world, and teenagers and young people are more likely to succumb to it [8].
In a meta-analysis conducted by Salarvand et al., the overall prevalence of Internet addiction was 31.51% among Iranian students [9].Excessive Internet use has been linked to a variety of sleep-related problems, including poor sleep quality, extended sleep latency, short sleep durations, and sleep disruptions.It has also been shown to increase the use of sleeping pills and have negative efects on everyday functioning [10].In another meta-analysis including 35,684 participants, the overall odds ratio of sleep disorders caused by Internet addiction was calculated to be 2.20 [11].Internet users lacking self-control are more likely to sufer from poor sleep quality as a result of their uncontrolled online behavior (such as staying up late) [10].In a former study conducted on a population of medical students, the prevalence of poor sleep quality was 61.7%, which was associated with daily life behaviors, especially excessive Internet usage [12].Epidemiological studies have shown that sleep disturbance is associated with adverse health outcomes, including obesity, type 2 diabetes, cardiovascular disease, hypertension, and premature death [13].In general, the relationship between Internet addiction and sleep quality has been shown in various studies.But other psychosocial characteristics which aggravate Internet addiction is less considered [7,14].Systematic reviews and meta-analyses have provided a signifcant understanding t into the relationship between Internet addiction and sleep quality and disorders [9,11].One of the limitations of cross-sectional studies is the choice of study courses to conduct the study, which does not refect the state of Internet use and the sleep quality of the participants throughout the year [7,10].
Te efect of Internet addiction on sleep quality and the correlation between Internet use and sleep disorders among college students needs more attention.Considering the increase in the use of the Internet in Iran, especially among students, the relationship between Internet addiction and sleep disorders, and the importance of this issue to minimize the inappropriate use of the Internet, the present study aims to determine the efect of Internet addiction and sleep and communication disorders.Tese two were designed among the students of the Shiraz University of Medical Sciences.Tis study generally examines these two issues: comparison of sleep quality between participants with Internet addiction and correlations between dimensions of sleep quality and Internet addiction.

Study Design and Population.
Tis study was conducted on students studying at the Shiraz University of Medical Sciences in 2018.Due to the fact that exposure (Internet addiction) and outcome (sleep disorder) information were taken from the subjects at the same time, the type of study was cross-sectional.In [15], the sample size based on formula n � z 2 pq/d 2 (p � 0.26, d � 0.05) was estimated to be 323 people and more than 400 (402 participants), according to attrition.Te sample size was selected from nine relevant faculties using a stratifed random sampling method.
In order to generalize the results, samples should have been selected from all university students.Terefore, a multistage sampling method was used.First, the proportion of the students of each faculty to the total number of university students was determined.Ten, by multiplying the obtained proportion by the sample size of the research, the proportion of each faculty was determined.Each faculty was considered to be stratifed, and we conducted simple random sampling in all strata.Ten, in the third stage, the selected people were confrmed if they met the eligibility criteria.Finally, the questionnaires were completed by referring to the students' classrooms.[4].Te reliability and validity of this questionnaire have already been confrmed by Cronbach's alpha coefcient of 0.93 [18].Also, in the study conducted in Iran, the content validity index for each item was higher than 0.83 and the average content validity index was equal to 0.89.Face validity was measured using the item importance index, and this index demonstrated that all items have an importance index higher than 1.5 [19].

Results
Out of 402 participants, 245 (60.9%) were female and 353 (87.8%) were single.Ph.D. and professional doctorate were the most common grades (49.3%), and 255 (63.4%) did not go to work (Table 1).109 participants (28.9%) were at risk for or had Internet addiction.Te average age of Internet addicts (27.66 ± 11.59) was higher than that of other groups, while the average grade of this group was lower than that of other groups (15.5 ± 2.32), which was not statistically signifcant (p � 0.206).Male gender, single participants, and Ph.D. and professional doctorate degrees were the most people at risk for or addicted to the Internet (Table 1).
Overall, 58 (14.4%) participants had poor sleep quality, of which 35 (60.3%) were women, 52 (89.7%) lived in urban areas, and most of them had university-educated parents.Moreover, the average age and grade point average of those with poor sleep quality were lower (21.96± 2.71 and 16.2 ± 1.5, respectively) than those with good sleep quality, but it was not statistically signifcant.Table 1 provides further demographic information.
According to Table 2, the average score of sleep quality in those with Internet addiction was higher than that of other compared groups (p � 0.026).Te average score of subjective sleep quality (p � 0.04), sleep disturbances (p � 0.005), and the use of sleeping medication (p < 0.001) was signifcantly higher in the group at risk of Internet addiction.Moreover, in those who had Internet addiction, the average score of habitual sleep efciency (p � 0.037) was signifcantly higher than that of those at risk or without Internet addiction.
Te results of this study revealed that the highest percentage of poor sleep quality was in those who are addicted to the Internet (60%), while the lowest percentage was observed in the group without addiction (27%), and in the at-risk group, poor sleep quality and good sleep quality were equal (50%) (Figure 1).

Discussion
Adequate sleep is essential for proper body function.With the increasing popularity of smart phones and the increasing use of the Internet, especially among the youth, using them before bedtime has become a habit, which can negatively afect their quality of sleep [10].Terefore, the present study was conducted with the aim of determining the relationship between Internet addiction and sleep quality in a population of university students.
Based on the results of our study, 28.9% of all the people under study were at risk of Internet addiction or had Internet addiction, and this result is higher than the rates obtained from Vietnam University (21.2%) [20] and lower than results of other countries such as Bangladesh (49.2%) and Jordan (40.0%) [21,22].Te prevalence of poor sleep quality found in this study is 14.4% which is lower than that of other studies in Iran and Bangladesh [15,21], and the Te Scientifc World Journal

Association between Demographic Characteristics, Internet Addiction, and Sleep
Quality.Derived from our results, there was no signifcant diference between the age and gender variables with sleep quality and Internet addiction, which was consistent with the results of the studies by Gupta et al. [23] and Sagar and Hülya [24].However, other studies have demonstrated that Internet addiction was more prevalent among men at a young age and did not have signifcant gender diferences in sleep quality [25,26].Although there are age-related diferences in sleep duration and quality, as well as Internet usage, the fact that the university students in this study were in the same age group may have infuenced this result.In addition, considering the necessity of sleep for the survival of any living thing in this    Te Scientifc World Journal context, the fact that sleep is not a gender-specifc variable may reveal the result of this study [24].Te present study found no signifcant efect of the place of residence, level of education, and marital status on Internet addiction and sleep quality of the students.Consistently, the study by Tahir et al. [1] found no signifcant efect of residence on Internet addiction but stated that participants who lived in urban areas had poorer sleep quality than those who lived in rural areas.Our study was not in line with the results of studies by Romero Blanco et al. [25] and Cheng et al. [27] who found that undergraduate students had poorer sleep quality than graduate students.Te study by Zhang et al. [20] stated that single people were not at risk of sleep-related problems.Te study by Karimi et al. [28] also noted that the rate of Internet addiction was higher among single students, and these results were not consistent with those of our study.Most of the people studied were single, which probably afected the results of the study.

Internet Addiction and Sleep Quality. A comparison of the scores of sleep quality between participants without
Internet addiction and those with diferent degrees of Internet addiction revealed the mean score of the Global PSQI index was higher in at-risk participants of Internet addiction and Internet addicts than in other participants; this result was also maintained in the dimensions of subjective sleep quality, habitual sleep efciency, sleep disturbances, and use of sleeping medication.Tis fnding was consistent with the results of a study in southern Taiwan and a multinational cross-sectional survey that was carried out in seven countries.Tese studies introduced various components of Internet addiction as signifcant predictors of subjective sleep quality, sleep disturbance, use of sleep medication, sleep duration, daytime dysfunction, and sleep latency [1,10].In general, some studies have also stated Internet addiction as a predictor of sleep quality of students, children, and teenagers [29,30].So, a study stated that Internet addiction signifcantly afects the sleep quality of students, and with an increase of 1 unit in the Internet addiction score, the risk of low sleep quality increases by 8.7% [24].Tis fnding could be due to the mechanisms related to the use of electronic devices in bed harming sleep with cognitive, emotional, or physiological stimulation; it can also be said that exposure to intense light leads to the suppression of melatonin secretion and sleep delay, which can increase consciousness and sleep disorders [11,31].

Correlation between Internet Addiction and Sleep Quality.
Also, the fndings of our study showed that there was a positive week correlation between Internet addiction and subjective sleep quality, sleep latency, sleep disturbances, sleep duration, daytime dysfunction, habitual sleep efciency, use of sleeping medication, and the global PSQI; this fnding was consistent with that of studies conducted in Taiwan [10], Saudi Arabia [32], and South Asia [33].
Regarding long sleep latency and Internet addiction, it can be noted that stimulation of the central nervous system through games, watching online movies before sleep, and the emission of blue light through the screen can lead to the suppression of melatonin secretion from the well-known pineal gland, which, in turn, can be an efective factor in long-term sleep latency [34,35].
Studies conducted in South Korea [36] and China [37] on the link between Internet use and sleep duration have identifed a signifcant negative association between Internet use and sleep duration, which are not consistent with our results.Tis can be because staying awake at night and spending time on the Internet lead to a longer sleep duration during the day.In addition, this result can lead to disruption of normal daily functions.
Te identifcation of a positive correlation between Internet addiction and the use of sleep medication in this study and other studies with similar results [1,10] may imply that one of the most common ways to tackle sleep disorders is the use of sleep medications; with Internet addiction and increased sleep disorder, the tendency to take medical sleep medications increases [10,38].

Strengths and Limitations.
Te strengths of the study can be mentioned as follows: (i) Its appropriate sample size (ii) Examining the prevalence of Internet addiction (iii) Using a valid questionnaire as an index of Pittsburgh sleep quality to determine the severity of sleep disorder (iv) In addition, students of diferent educational levels were included in the study, so a signifcant proportion of participants were masters' and Ph.D. students and professional doctorates.
Te limitations of the study can be mentioned as follows.
Despite the strength of our research, this study was a cross-sectional study, and therefore, the results do not indicate a causal relationship; we have only been able to clarify the relationship between Internet addiction and sleep quality, but due to our research methodology, we did not determine its cause and efect.In addition, since the sample includes students from one university, the results cannot be considered representative of the entire country.

Conclusion
Te results of the research show that Internet addiction is considerably correlated with diferent aspects of sleep quality in students.Considering the signifcant role of students in the future as professionals, it is highly advised that educational programs and workshops about harms of Internet addiction be provided to students via social media and other platforms.Terefore, according to the results of this study, which is a confrmation for the results of similar studies, it is recommended that health service providers should provide the necessary awareness in this feld to the public, including students' parents.Also, health policymakers and the media should provide the necessary plans to inform people through booklets and brochures.

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Te Scientifc World Journal 5.1.Recommendations for Future Studies.Based on this, it is suggested that future studies that investigate the relationship between Internet addiction and sleep quality should be conducted with the participation of people in diferent age groups.Also, future studies can be expanded by adding diferent variables to this feld and investigating diferent aspects.In addition, it is suggested that studies be designed to examine the causality between sleep quality and Internet addiction.

Figure 1 :
Figure 1: Percentage of students at levels of sleep quality among the three levels of Internet addiction.
[17]otal score was measured by summing the scores of seven dimensions (range, 0-21), and a total score higher than fve indicated poor sleep quality[16].Te Iranian version of this questionnaire has been confrmed by Moghaddam et al.Cronbach's alpha coefcient was calculated to be 0.77, indicating the internal consistency of the questionnaire[17].Tis questionnaire, which was prepared by Kimberly Young, contains 20 questions on a fve-point Likert scale to measure people's dependence on the Internet, ranging from 1 (rarely) to 5 (always), and was scored between 20 and 100.Based on the scores obtained from this scale, people are divided into three groups, including no Internet addiction (scores from 20 to 49), at risk of Internet addiction (scores from 50 to 79), and having Internet addiction (scores from 80 to 100) subjective sleep quality, sleep latency, sleep duration, habitual sleep efciency, sleep disturbances, use of sleeping medications, and daytime dysfunction.Te questions related to each dimension were scored from zero to three: score zero indicated no sleep disturbance, score one showed moderate sleep disturbance, score two was related to severe sleep disturbance, and score three showed very serious sleep 2 Te Scientifc World Journal disturbance.

Table 1 :
Demographic characteristics of the students based on their sleep quality and Internet addiction.
and these results can confrm that Internet addiction is known as one of the factors afecting the low quality of sleep; on the other hand, changes in the prevalence of Internet addiction among diferent countries may be due to diferences in evaluation methods as well as cultural and social factors.

Table 2 :
Comparison of sleep quality between participants with Internet addiction.

Table 3 :
Correlations between dimensions of sleep quality and Internet addiction.