The exacerbation of depression, hostility, and social anxiety in the course of Internet addiction among adolescents: A prospective study Chih-Hung Ko a,b,c , Tai-Ling Liu a , Peng-Wei Wang a , Cheng-Sheng Chen a,c , Cheng-Fang Yen a,c , Ju-Yu Yen a,d, ⁎ a Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan 807 b Department of Psychiatry, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung City, Taiwan 812 c Department of Psychiatry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung City, Taiwan 807 d Department of psychiatry, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan 801 Abstract Background: In adolescent populations worldwide, Internet addiction is prevalent and is often comorbid with depression, hostility, and social anxiety of adolescents. This study aimed at evaluating the exacerbation of depression, hostility, and social anxiety in the course of getting addiction to Internet or remitting from Internet addiction among adolescents. Method: This study recruited 2293 adolescents in grade 7 to assess their depression, hostility, social anxiety and Internet addiction. The same assessments were repeated one year later. The incidence group was defined as subjects classified as non-addicted in the first assessment and as addicted in the second assessment. The remission group was defined as subjects classified as addicted in the first assessment and as non- addicted in the second assessment. Results: The incidence group exhibited increased depression and hostility more than the non-addiction group and the effect of on depression was stronger among adolescent girls. Further, the remission group showed decreased depression, hostility, and social anxiety more than the persistent addiction group. Conclusions: Depression and hostility worsen in the addiction process for the Internet among adolescents. Intervention of Internet addiction should be provided to prevent its negative effect on mental health. Depression, hostility, and social anxiety decreased in the process of remission. It suggested that the negative consequences could be reversed if Internet addiction could be remitted within a short duration. © 2014 Elsevier Inc. All rights reserved. 1. Introduction More than 90% of adolescents use the Internet to get information [1]. The Internet is one of the most powerful media of the 21st century and has revolutionized education and social communication in adolescents [2]. For adoles- cents, the Internet is also an important source of health- related information [3]. However, Internet addiction, which can be defined as the loss of control over Internet use and its resulting negative consequences, is common in adolescents [4]. Epidemiological studies reveal that Internet addiction occurs in 1.4–17.9% of adolescents in both western and eastern populations [5–7]. This indicates that Internet addiction is a major mental health problem in adolescents worldwide. Therefore, a clear understanding the mental health effects of Internet addiction in adolescents is essential. Epidemiological studies agree that Internet addiction in adolescents is associated with depressive symptoms and social anxiety [5,8,9]. The same association has also been reported in college students [10]. However, the causal relationship between Internet addiction and depression and social anxiety could not be confirmed in previous cross- section studies. Social anxiety is generally lower during online interaction than during face-to-face interaction, especially in subjects with high social anxiety [11]. Depressive subjects also experience lower social anxiety and hostility during online interaction [11,12]. Thus, we hypothesized that adolescents who have depression or social Available online at www.sciencedirect.com ScienceDirect Comprehensive Psychiatry xx (2014) xxx – xxx www.elsevier.com/locate/comppsych ⁎ Corresponding author at: Department of Psychiatry, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, No. 68, Jhonghua 3rd Rd, Cianjin District, Kaohsiung City 80145, Taiwan. Tel.: +886 7 3121101x6822; fax: +886 7 3134761. E-mail address: yenjuyu@cc.kmu.edu.tw (J.-Y. Yen). http://dx.doi.org/10.1016/j.comppsych.2014.05.003 0010-440X/© 2014 Elsevier Inc. All rights reserved.