Adding up risks: Sexual debut and substance use among Italian university students.

Adolescence and youth are periods of great changes in an individual's life, during which experiencing first events of the transition to adulthood and, sometimes, violating social norms. Literature has identified an association of risk behaviours with timing of first sexual intercourse, but scant information is available about their relationship with the use of protection or the choice of a casual partner. This study focuses on the relation between initiation of risk behaviours (get drunk and drug use) and initiation of intercourse. Using event history analysis - also in their competing risk form - on data on Italian university students collected in 2000-2001 and in 2017, we intend to verify to what extent the initiation and the timing to risk behaviours is associated with the circumstances of first intercourse (timing, use of protection, type of partner), and if and how initiation to risk behaviours interacts differently with age at sexual debut. Our results show that in a country such as Italy, where family and sexual norms are relatively traditional, young people who got drunk, used marijuana or ecstasy at least one time in their life are more likely to experience risky sexual intercourse.