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.