Longitudinal study shows that addictive Internet use during adolescence was associated with heavy drinking and smoking cigarettes in early adulthood.

Aim: Existing studies showing an association between substance use disorders and Internet addiction have been limited due their cross-sectional design. This longitudinal study investigated the association between addictive Internet use during adolescence and heavy drinking and cigarette smoking in early adulthood.

Methods: We focused on middle school students from the Korea Youth Panel Study who were 15 in 2003:1804 who did not drink alcohol and 2277 who did not smoke. Multivariate logistic analysis investigated the relationships between Internet use at the age of 15, with regard to location, time spent and reason for use, and drinking and smoking at the age of 20.

Results: Using the Internet for chatting, games and adult websites at the age of 15 had a significant association with heavy drinking at the age of 20. The Internet café as the location for Internet use at the age of 15 was associated with smoking behaviour at the age of 20.

Conclusion: This study confirmed significant associations between addictive use of the Internet at the age of 15 and heavy drinking and cigarette smoking at the age of 20. The findings demonstrated the negative effects of addictive Internet use, one of the biggest problems with adolescents.