Background Excessive smartphone use has been associated with numerous psychiatric disorders. This study aimed to investigate the prevalence of smartphone addiction and its association with depression, anxiety, and attention-deficit hyperactivity disorder (ADHD) symptoms in a large sample of Korean adolescents. Methods A total of 4512 (2034 males and 2478 females) middle- and high-school students in South Korea were included in this study. Subjects were asked to complete a self-reported questionnaire, including measures of the Korean Smartphone Addiction Scale (SAS), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), and Conners-Wells’ Adolescent Self-Report Scale (CASS). Smartphone addiction and non-addiction groups were defined using SAS score of 42 as a cut-off. The data were analyzed using multivariate logistic regression analyses. Results 338 subjects (7.5%) were categorized to the addiction group. Total SAS score was positively correlated with total CASS score, BDI score, BAI score, female sex, smoking, and alcohol use. Using multivariate logistic regression analyses, the odds ratio of ADHD group compared to the non-ADHD group for smartphone addiction was 6.43, the highest among all variables (95% CI 4.60–9.00). Conclusions Our findings indicate that ADHD may be a significant risk factor for developing smartphone addiction. The neurobiological substrates subserving smartphone addiction may provide insights on to both shared and discrete mechanisms with other brain-based disorders.

Cleidocranial dysplasia (CCD) is an autosomal dominant disorder caused by haploinsufficiency of the RUNX2 gene. In this study, we analyzed by direct sequencing RUNX2 mutations from eleven CCD patients. Four of seven mutations were novel: two nonsense mutations resulted in a translational stop at codon 50 (Q50X) and 112 (E112X); a missense mutation converted arginine to glycine at codon 131 (R131G); and an exon 1 splice donor site mutation (donor splice site GT/AT, IVS1 + 1G > A) at exon 1-intron junction resulted in the deletion of QA stretch contained in exon 1 of RUNX2. We focused on the functional analysis of the IVS1 + 1G > A mutation. A full-length cDNA of this mutation was cloned (RUNX2Deltae1) and expressed in Chinese hamster ovary (CHO) and HeLa cells. Functional analysis of RUNX2Deltae1 was performed with respect to protein stability, nuclear localization, DNA binding, and transactivation activity of a downstream RUNX2 target gene. Protein stability of RUNX2Deltae1 is similar to wild-type RUNX2 as determined by Western blot analysis. Subcellular localization of RUNX2Deltae1, assessed by in situ immunofluorescent staining, was observed with partial retention in both the nucleus and cytoplasm. This finding is in contrast to RUNX2 wild-type, which is detected exclusively in the nucleus. DNA binding activity was also compromised by the RUNX2Deltae1 in gel shift assay. Finally, RUNX2Deltae1 blocked transactivation of the osteocalcin gene determined by transient transfection assay. Our findings demonstrate for the first time that the CCD phenotype can be caused by a splice site mutation, which results in the deletion of N-terminus amino acids containing the QA stretch in RUNX2 that contains a previously unidentified second nuclear localization signal (NLS). We postulate that the QA sequence unique to RUNX2 contributes to a competent structure of RUNX2 that is required for nuclear localization, DNA binding, and transactivation function.

BackgroundThis cross-sectional study investigated the impact of life satisfaction and happiness, as well as the prevalence and correlates of depressive symptoms in a large sample of university students.MethodsWe included 2338 students at 6 universities in 1 metropolitan city and 2 provinces of Korea. Depressive symptoms were assessed by the Beck Depression Inventory, and scores of 16 or higher were categorized as the presence of depression. Various sociodemographic, life satisfaction, happiness, and clinical factors (alcohol consumption and sleep quality) were measured. According to the presence of depression, sociodemographic, life satisfaction, happiness, and clinical characteristics were compared using statistical analyses. Further, a logistic regression model was constructed to examine the impact of life satisfaction, happiness, and clinical factors on depression.ResultsAmong participants, 13.4% were identified as having depression. Life satisfaction and happiness were associated with a lower risk of depression, while hazardous alcohol drinking and poor sleep quality were related to a higher risk of depression. In addition, female gender, subjective body shape as obese, and insufficient pocket money were found to be significant correlates of depressive symptoms.ConclusionsThis study demonstrated possible risk and protective factors of underlying depressive symptoms. Especially, our findings suggest that improvement in life satisfaction and happiness would be important in the prevention and management of depression. Our findings may contribute to developing specialized mental health programs for prevention, screening, and treatment of depression among university students.