Background and Aims: A definition of gaming disorder (GD) was introduced in ICD-11. The purpose of this study was to develop a short screening test for GD, utilizing a reference GD group. It also sought to estimate the prevalence of GD among individuals, representative of the general young population in Japan.Methods: Two hundred eighty one men and women selected from the general population, aged between 10 and 29 years, and 44 treatment seekers at our center completed a self-reported questionnaire comprising candidate questions for the screening test. The reference group with ICD-11 GD was established, based on face-to-face interviews with behavioral addiction experts, using a diagnostic interview instrument. The questions in the screening test were selected to best differentiate those who had GD from those who did not, and the cutoff value was determined using the Youden index.Results: A nine-item screening test (GAMES test) was developed. The sensitivity and specificity of the test were both 98% and the positive predictive value in the study sample was 91%. The GAMES test comprised two factors, showed high internal consistency and was highly reproducible. The estimated prevalence of GD among the general young population was 7.6% (95% confidence interval; 6.6–8.7%) for males and 2.5% (1.9–3.2%) for females, with a combined prevalence of 5.1% (4.5–5.8%).Discussion and Conclusion: The GAMES test shows high validity and reliability for screening of ICD-11 GD. The estimated prevalence of 5.1% among the general young population was comparable to the pooled estimates of young people globally.

Study Objectives: Sleep problems and problematic Internet use have important implications for adolescent health; however, there have been no large-scale surveys using comprehensive measures. We examined the association between Internet use duration and sleep problems among Japanese adolescents. Methods: We used data from the Lifestyle Survey of Adolescents collected in 2012, 2014, and 2017. We calculated the change in sleep status (insomnia, sleep duration, bedtime, and sleep quality) and Internet usage (screen time and services such as Internet surfing, social media use, streaming such as YouTube, and online gaming). A binary logistic model was estimated for insomnia. Generalized ordered logit models were employed for the ordinal outcomes (sleep duration, bedtime, sleep quality, and multidimensional sleep health). Sampling weights were constructed based on participation rate on survey years and selection rates from population statistics. Results: We analyzed data from 248 983 adolescents. Sleep status was unchanged; however, many adolescents used more Internet services and for longer durations. The odds ratio of Internet screen time for all sleep problems (insomnia, shorter sleep duration, later bedtime, and worse sleep quality) gradually declined. Longer Internet screen time (>5 hours) was strongly associated with all sleep problems. Internet services were also associated with sleep problems; particularly, social media use and online gaming were linked to later bedtimes. Conclusions: Despite the decreased strength in the association between Internet usage and sleep problems, longer Internet time was strongly associated with sleep problems. Public health interventions should consider Internet use as an intervention target to improve adolescents’ health.

We aimed to examine the association between loneliness and developing alcohol dependence or hazardous alcohol use. A cohort study was conducted utilizing data from a nationwide internet survey in 2021 and 2022 in Japan. A total of 15,854 follow-up participants (55% men, with a mean age of 52.8 years) were divided based on AUDIT scores: nondrinkers (AUDIT: 0), low-risk drinkers (AUDIT: 1–7), medium-risk drinkers (AUD: 8–14), high-risk drinkers (AUDIT: 15–19), and probable alcohol dependence (AUDIT: 20–40). The University of California, Los Angeles Loneliness Scale (Version 3), a short-form three-item scale, was used to assess loneliness (high loneliness score of ≥6). The prevalence of high loneliness was higher in nondrinkers than that in low- and medium-risk drinkers, i.e., 22%, 18%, and 17%, respectively, as well as in high-risk drinkers (32%) and those with probable alcohol dependence (43%) compared to non-high-risk drinkers (19%). After adjusting for various factors (sociodemographic, social isolation, psychological distress, and smoking), non-high-risk drinkers (AUDIT: 0–14) with high loneliness were more likely to become high-or-over-risk drinkers (AUDIT: 15–40) than those without high loneliness, with adjusted risk ratios of 1.45 (95% confidence interval: 1.08–1.96) through multivariable binary logistic regression. Among non-high-risk drinkers, people with high loneliness scores at baseline were associated with increased high-risk drinking patterns with probable alcohol dependence.

Background: In this study, we aim to estimate the prevalence of heated tobacco product (HTP) smokers three years after the launch of HTPs in Japan.Methods: Our study, performed in February 2018 in Japan, had a cross-sectional population-based design. A total of 4,628 adult participants (2,121 men and 2,507 women) were randomly sampled from all regions of Japan. The response rate was 57.9%. Interviews were conducted by trained investigators who visited participants’ homes. A survey on current (past 30 days) and lifetime tobacco use (including e-cigarettes and HTPs), as well as numerous sociodemographic factors, was conducted.Results: The age-adjusted rates (95% confidence interval) and estimated number of lifetime-HTP smokers were 14.1% (12.5-15.6%; 7.11 million men) and 3.7% (2.9-4.4%; 1.99 million women). The age-adjusted rates (95% confidence interval) for current HTP smokers were 8.3% (7.1-9.6%; 4.21 million men) and 1.9% (1.3-2.4%; 1.02 million women). Multiple variables were found to be associated with a higher prevalence of current HTP use, including being male, aged 20–39 years old, a current Internet user, a risky drinker, or a heavy episodic drinker. HTP use was also higher among men with 10 years or more of education, women with 15 years or less of education, and men with middle- or high-level household incomes.Conclusion: We concluded that HTP use has increased substantially in Japan. However, regulations for HTPs are weaker than those for combustible cigarettes in Japan. Thus, HTPs should be subjected to the same regulations as combustible tobacco products.