[Internet and associated factors in adolescents in the Community of Madrid]

To determine the type of Internet use carried out by adolescent schoolchildren and identify factors associated with high use.

Descriptive, cross-sectional study using a self-administered questionnaire.

Secondary and High School Education Centres of the Autonomous Community of Madrid (rural and urban areas).

Third and fourth year Secondary and 1st and 2nd year High School pupils from 9 centres. A total of 1328 of the 1330 pupils present in the classrooms during the school term January-April 2007.

Dependent variable: intensity of Internet use: very high, high, medium, low and none. Information on socioeconomic variables, smoking, drugs and drinking habits, mental health, academic failure and use of mobile telephone. An analysis was made using a two-step logical regression.

The mean age of the sample was 15 years, with an equal number of males and females. A total of 93.1% used the Internet, of which 5.3% (95% CI: 4-6.5%) had a very high use, 16.7% (95% CI: 14.5-18.6%) high use, 71.1% (95% CI: 68.2-73.2%) low to medium use, and 6.9% (95% CI: 5.6-8.4%), did not use it. Very high use of the Internet is associated with the male sex (OR=4.28;95% CI:2.37-7.72), being 16 years or over (OR=2.14;95% CI:1.23-3.72) and is dependent on the mobile phone (OR=5.19;95% CI: 2.97-9.08). An association with alcohol consumption was observed in the high use group (OR=1.89; 95% CI:1,35-2,65). Academic failure is more common among those who do not use the Internet (OR=1.61; 95% CI:1.02-2.55).

Given the relationship found between high Internet use and mental health problems and bad habits, it is important to perfect standardised tools to detect and evaluate the compulsive use of the Internet as well as aid to its responsible use.