These moral paradigms include commercial morality, prohibition-criminalization, vice regulation, public health, and rehabilitation. Both Britain and the U.S. were dominated by the commercial paradigm in the 19th century. International opium conventions, held from 1912 to 1913, greatly restricted the commercial morality and developed a successful public health approach to opiates. The U.S. shifted toward a prohibition-criminalization approach for drug addicts, whereas Britain maintained a public health approach. The 1980s, however, has seen the growth of a black market in heroin, a shift away from long-term maintenance of opiate addicts in Britain, and the criminalization of many heroin user-dealers. While British policy toward opiate addicts allows them to legally obtain opiates from government clinics or their general practitioners, physicians have chosen to greatly restrict opiate maintenance. 98 references