Smoking habits, alcohol consumption, use of drugs, and gambling by pupils from secondary schools. Frequency of smoking / age when smoking first cigarette / who smoke in family / consumption of alcoholic beverages / type of drinks / occurrence of drunkenness / use of softdrugs and-or harddrugs / attitude to alcohol, smoking hashish / place and frequency of gambling / expenditures for gambling. Background variables: basic characteristics/ place of birth/ characteristics of parental family/household/ education/ religion