Research Article European Addiction Eur Addict Res Received: September 5, 2019 Research DOI: 10.1159/000506738 Accepted: February 21, 2020 Published online: March 13, 2020 Problematic Smartphone Use, Screen Time and Chronotype Correlations in University Students a a b a Pavle Randjelovic Nenad Stojiljkovic Niko Radulovic Nikola Stojanovic c Ivan Ilic a b Department of Physiology, Faculty of Medicine, University of Nis, Niš, Serbia; Department of Chemistry, Faculty of c Science and Mathematics, University of Nis, Niš, Serbia; Department of Pathology, Faculty of Medicine, University of Nis, Niš, Serbia Keywords type. Those students spent significantly more time on their Students · Chronotype · Screen time · Problematic phones compared to the non-addicted ones. There was no smartphone use statistically significant difference between the number of male and female students with problematic smartphone use. The best predictors of problematic smartphone use were Abstract longer daily smartphone screen time and evening chrono- Background: Besides numerous advantages and commodi- type personality. Conclusions: The results of our study ties offered by smartphones, there are obvious unhealthy ef- showed that a significant number of students of medicine fects. The global trend of an increase in the frequency of us- showed problematic smartphone use. There was a strong age of smartphones, that is, prolonged screen time, is close- correlation between extensive screen time and the level of ly related to problematic smartphone use. The aim of our problematic smartphone use in the studied population. study was to measure the level of problematic smartphone © 2020 S. Karger AG, Basel use in a student population through the assessment of the smartphone screen time and the determination of the stu- dent chronotype, as well as through the correlation between Introduction these variables. Methods: The participants were students of medicine of both sexes. Problematic smartphone use was In 1997, the term smartphone was introduced by the measured by the short version of the Smartphone Addiction manufacturer Ericsson to point out the advanced features Scale. Smartphone screen time was assessed by the free An- of a new generation of mobile phones [1]. Ever since, the droid application Quality Time. Chronotype was established smartphones are becoming irreplaceable in an everyday by the Morningness-Eveningness Questionnaire. Results: Al- life and are offering a wide spectrum of applications for most one quarter (22.7%) of students involved in our study news, entertainment, communications, and education. could be classified as being “smartphone-addicted”. The stu- Smartphones have touchscreens, Internet connection, dents with problematic smartphone use more frequently possibility to add new applications, and other interesting (statistical significance) belonged to the evening chrono- functions such as a digital camera, GPS navigation, and a © 2020 S. Karger AG, Basel Pavle Randjelovic Department of Physiology Faculty of Medicine, University of Niš E-Mail [email protected] Bulevar Dr Zorana Djindjica 81, 18000 Niš (Serbia) www.karger.com/ear E-Mail pavleus @ gmail.com Downloaded by: National Univ. of Singapore 137.132.123.69 - 3/15/2020 4:41:49 PM music player. Besides numerous advantages and commod- Chronotype refers to the preference for sleep-wake ities offered by smartphones, there are obvious unhealthy timing: for example, morning types go to bed, get up, and effects related to their usage. Some examples of such un- experience peak alertness and performance earlier in the wanted effects are neck pain syndrome [2] or traffic acci- day than do evening types [12]. Individual circadian type dents [3]. Recent studies showed that increased screen time can be clustered into 3 categories as “morning type”, “in- is connected to the sleep disturbances and depression [4]. termediate type”, and “evening type” with the normal dis- Also, the global trend of the rise in the frequency of usage tribution around the middle [13]. of smartphones, termed as “screen time”, is closely related to problematic smartphone use [5]. Lin et al. [6] showed Aim of the Study that problematic smartphone use has similar aspects to The aim of our study was to measure the level of prob- substance addiction. The term “smartphone addiction” is lematic smartphone use in a student population and the not an official disorder and so it is recommended to use the screen time of smartphones and to determine the chro- term problematic smartphone use. The usage of the word notype of the students. Also, the significance of the cor- addiction in the context of mobile phone overuse is also relation between studied variables was assessed. problematic due to stigmatization of users [7]. When we talk about mobile phones, the problematic smartphone use could start when usual behavior, such as Material and Methods owning a mobile phone for communication or security reasons, starts to produce negative consequences and the The experimental proposal followed the principles suggested in user becomes increasingly addicted [8]. Owning a mobile the 2013 Declaration of Helsinki and was approved by the local phone for primary purposes becomes secondary and the Ethical Committee. The study was carried out at the Faculty of Med- owner starts to use his phone for entertainment reasons icine, University of Niš (Serbia) during March 2018. The partici- pants were second-year students of medicine, 20–22 years of age, of solely. Over time, a smartphone user could develop pro- both sexes. The study was based on simple random sampling. The gressively dangerous behavior, such as texting while driv- involvement in the study was strictly on a voluntary basis and anon- ing a car, and in the end, the person reaches a point where ymous. Before the commencement of the study, all participants he cannot control smartphone usage. The addiction pro- were informed about the study design. All enrolled students signed cess differentiates the need and desire. In other words, a an informed consent document. The students could drop out of the study at any moment without any consequence to them. The inclu- smartphone user starts with the desire to use his phone sion criteria were having and using an Android-based mobile and ends up feeling the need to use it. This overlapping phone. The exclusion criteria were usage of sedative medications or point is showing the transition from safe behavior, being psychoactive substances, the existence of recent stressful situations, pleasant with minor unhealthy effects, to addictive be- and other sleep-interfering reasons. Primary outcomes of the study havior, where the urge (physical and/or mental) replaced were the problematic smartphone use level, smartphone screen time, screen unlock number, and chronotype score. the desire as a motivation factor. It is believed that this Problematic smartphone use was measured by the short ver- type of problematic smartphone use uses the same neural sion of the Smartphone Addiction Scale (SAS-SV) [14]. This as- pathways involved in substance use disorder [9]. sessment tool was created in South Korea and published in the The constant use of mobile phone gives rise to the con- English language in 2013. It has 10 questions with answers on a cept of Nomophobia (No-Mobile-Phobia), which is the scale from 1 (completely agree) to 6 (completely disagree). The to- tal score could range from 10 to 60, with higher values indicating fear of losing contact with a mobile phone [10]. Griffiths higher addiction from a smartphone. The questionnaire showed [10] suggests that everything that produces a feeling of ex- good validity and internal consistency (Cronbach’s alpha 0.91). citement can cause an addiction. Having that in mind, the The authors of SAS-SV proposed cutoff values for the prediction cause of problematic smartphone use could be the fact that of problematic smartphone use as 31 for males and 33 for females. the usage of smartphones brings a feeling of excitement. Smartphone screen time and screen unlock number were as- sessed by the free Android application Quality Time [15]. The data So if a certain type of behavior results in a sense of excite- were collected for 14 consecutive days, and the average for 14 days ment or helps to reduce negative or unpleasant feelings, was calculated for each participant and those values were used for then such behavior is intensified and the person continues further analysis. with it for pleasure or to reduce the unpleasant situation. Chronotype was assessed by the Morningness-Eveningness Problematic smartphone use gives a sense of pleasure to Questionnaire (MEQ) [16], a self-rating questionnaire that con- sists of 19 items with a total score ranging from 16 to 86. Higher consumers as a result of usage and relieves them from anx- scores indicate greater morningness, while lower scores indicate iety or stress [11]. Therefore, it could be assumed that this more evening type. very scenario causes addiction-like processes. The average grade was self-reported by study participants. 2 Eur Addict Res Randjelovic/Stojiljkovic/Radulovic/ DOI: 10.1159/000506738 Stojanovic/Ilic Downloaded by: National Univ. of Singapore 137.132.123.69 - 3/15/2020 4:41:49 PM Table 1. Comparison of BMI, average grade, MEQ score, smartphone screen time, and screen unlocks between smartphone-addicted and non-addicted students Addicted Non-addicted p value d BMI 21.88±3.22 21.94±3.13 0.95 0.019 Average grade 8.65±0.88 8.64±0.62 0.97 0.013 MEQ score 44.05±6.15 48.41±10.29 0.042 0.514 Smartphone screen time, min 301.5±103.4 208.7±133.6 0.011 0.777 Screen unlocks, n 177.2±67.25 115.8±79.74 0.006 0.832 Values are represented as mean ± SD. BMI, body mass index; MEQ, Morningness-Eveningness Questionnaire. The body mass index (BMI) was calculated from body classifying students to those with and without problem- weight and height measured by standard equipment by one of the atic smartphone use, 31 points for males and 33 for fe- authors.