Life history, social background, first contacts with drugs, first contacts with the law. Legal sources of income: social benefits, regular job, rent subsidy / housing situation, expenditures for housing, telephone, electricity and gas / participation in methadon program / attempts made to kick the habit in hospital or drug rehabilitation centre / attitude to drugs and drug scene, motives to use drugs, propensity to experiment with drugs, wish to stop, having non-using friends, being avoided by other people. Regarding week before interview: purchases of various types of drugs, money spent for food, clothes, transportation, recreation, cigarettes etc. loans, savings etc. / earnings from various legal or illegal activities: moonlighting, selling drugs and drugs related activities, prostitution, theft, robbery, fencing, begging, gambling, loans / being robbed from drugs or lost drugs / consumption of various types of drugs, methadon / contacts with social assistance / contacts with police. Background variables: basic characteristics/ housing situation/ household characteristics/ characteristics of parental family/household/ occupation/employment/ income/capital assets/ education