There were several changes in drug legislation in Sweden during the 1960's and 1970's. In 1965, with the introduction of a new Penal Code, the maximum penalty for drug offenses was reduced from 1 to 2 years of imprisonment. However, with the Narcotic Drugs Act of 1968, the maximum penalty for aggravated cases was increased to 4 years. In 1972, the maximum penalty was increased to 10 years in an effort to harmonize Swedish legislation with international standards for drug trafficking penalties. In 1982, the maximum penalty for aggravated offenses committed by repeat offenders was increased to 16 years, and the legislation was further amended in 1985 to signal the gravity of drug offenses in general. Between 1980 and 1983, several centrally planned police operations occurred. Police drug units were given more resources, and drug squads were created in some of the larger police forces to target street drug markets. In 1991, the Stockholm County Police Force established a street market unit covering the entire county. An evaluation showed police actions disrupted the drug market in that drug dealers moved to other locations in a city or area. Once drug users left an area and the drug market had been dismantled, the general public felt more secure. The move from a more liberal ideology in the 1970's to a more restrictive ideology in the 1980's was effective in that tougher policies appeared to have preventive effects. Long-range preventive effects of the changed drug policies in Sweden are discussed. 27 references, 1 note, 3 tables, and 6 figures