Risky Health Behaviour among Adolescents

Sammanfattning: This thesis consists of four essays on risky health behaviour among adolescents. In the first paper, Young people and alcohol: an econometric analysis, the purpose was to analyse the determinants of adolescent drinking behaviour within an economic-theoretical framework. The results showed that having parents willing to supply alcohol increased the frequency of beer-, wine-, and spirits-consumption and the intensity of wine-, spirits-, and illicit-spirits consumption, as well as the probability of binge drinking and participation in consumption. Having received education about alcohol, narcotics and tobacco had a negative effect on the intensity of beer consumption. Living in a single-parent household showed no effect on drinking behaviour. Having a father who was currently unemployed showed a positive effect on binge-drinking, but a negative effect on the frequency of wine consumption.The second paper, Risk perceptions and alcohol consumption among young people, analysed alcoholism-risk perceptions, the determinants of these perceptions, and how these perceptions related to actual drinking behaviour. Three major conclusions were drawn: (1) that people overestimate the risks of alcoholism, (2) that these risk perceptions fall substantially with age, but nevertheless imply risk overestimation, and (3) that education about alcohol, narcotics and tobacco leads individuals to perceive risks more correctly and to have lower risk beliefs. An additional finding was that individuals with higher perceived risks were less likely to consume alcohol. In the third paper, Do they know what they are doing? Risk perceptions and smoking behaviour among teenagers, perceived risks of smoking-related lung cancer, the determinants of these risk perceptions, and how these perceptions related to smoking behaviour were analysed. The results showed that both smokers and non-smokers overestimated the risks of lung cancer. Furthermore, perceived risks were negatively related to age but were still overestimated in all age groups. Finally, the analysis showed that individuals with higher perceived risks were less likely to be smokers but risk beliefs had no effect on the number of cigarettes smoked. The fourth paper, Having the wrong friends? Peer effects in adolescent binge drinking, smoking, and illicit-drug use, analysed school-class-based peer effects in binge drinking, smoking, and illicit-drug use. Significant and positive peer effects were found for all three activities. By introducing school/grade fixed effects, the estimated peer effects were identified by variation in peer behaviour across school-classes within schools and grades, implying that estimates were not biased, due to endogenous sorting of students across schools. Further, endogeneity bias due to bi-directionality of peer effects was found for binge drinking and smoking. Controlling for this source of endogeneity resulted in even stronger peer effects. Overall, the study showed that substantial peer effects remained after taking account of the various pitfalls present when estimating such effects.