Smartphone usage in young adults: cross-sectional associations with physical activity, sleep, social isolation, academic achievement, and anxiety

Background: Smartphones play a vital role in daily life, especially for young adults and university students, providing benefits in communication, learning, and productivity. However, excessive use raises concerns about negative effects on physical and mental health. This study investigates the differences between low-risk and high-risk smartphone addiction users and explores links between overuse and physical activity, sleep quality, social isolation, anxiety, and academic performance among college students in Saudi Arabia. Methods: This cross-sectional analytic study included 80 undergraduate students aged 18–23 years from Taif University, Saudi Arabia. Participants filled out standardized questionnaires assessing smartphone addiction (SAS-SV), anxiety (GAD-7), social isolation (UCLA-7), and academic performance. Additionally, physical activity and sleep patterns were objectively measured using ActiGraph accelerometers. Results: Findings revealed that a significant majority (67.5%) of students were classified as high-risk smartphone addiction users. These individuals exhibited significantly elevated levels of social isolation (p=0.016) compared to their peers who utilized smartphones less often. Physical activity differed as well, high-risk users exhibited reduced step counts (p=0.01) and increased sedentary behavior (p=0.008). Sleep assessments also highlighted poorer outcomes in this group, including reduced sleep efficiency (p<0.001) and greater wake time after sleep onset (p<0.001). Among the high-risk users, a strong positive correlation was found between smartphone addiction and anxiety levels (r=0.40, p<0.001). Conclusion: High-risk smartphone use was linked to social isolation and poorer sleep quality, indicating negative effects on mental and physical health. Anxiety was identified as a statistically significant correlate of smartphone addiction scores in the regression analysis, suggesting emotional dysregulation plays a central role. High-risk smartphone users were also less physically active and more sedentary, though this was not directly tied to addiction scores.