2.2. Instrument

The questionnaire inquired about: 1) gender and age; 2) sociodemographics; 3) sleep duration during the week and weekends, sleep deprivation (SD) (difference in sleep duration equal/higher than 3 hours between weekdays and weekends) [42]; 4) screen time (computer use: standard; games, internet; social networks, emails,), 5) TV and mobile phone use; 6) earlier sexual behaviour; 7) violence: fights, use of weapons; 8) use of tobacco, alcohol and drugs. Answers were provided by Likert type scales inquiring if behaviours occurred and their frequency (e.g. how many hours a day do you sleep during the weekdays – or during the week end? how many times a month do you drink spirits? How many cigarettes do you smoke every month?), and for the purpose of the present study were dichotomised into a YES/NO behaviour occurrence basis.