Current status of substance abuse and HIV infection in Japan.

Japan has experienced an epidemic of methamphetamine (MAP) abuse three times: The first epidemic was from 1951 to 1957, the second epidemic was from 1970 to 1994, and the third epidemic started in 1995 and continues today. Fortunately, HIV infection is not as serious a problem in Japan as it is in other countries. The major route of HIV infection in Japan has been through male homosexual transmission. In cumulative number, homosexual transmission accounted for 63% of the 11,146 HIV-positive patients and 40% of 5,158 AIDS patients as of December 30, 2011. Intravenous drug use accounted for 0.3% and 0.4% of these cases, respectively. Drug abuse has changed during the past 20 years in Japan. The changes are summarized as follows: There has been (1) a remarkable decrease in solvent abuse, (2) a stabilization of MAP abuse, (3) a penetration of cannabis abuse, (4) an emergence of evasive drug abuse, and (5) a silent increase in medical drug dependence. This implies that (1) there has been a change from a "solvent dominant type" of use to a "cannabis dominant type," that is, from a "Japanese type" to a "Western type," (2) a shift to drugs which do not have a high potential to cause drug-induced psychosis, and (3) a shift from conduct that leads to arrest to conduct that does not lead to arrest. Regardless of whether the drug use is illicit or not, drug dependence is a mental disorder. Japan is urged to deal with drug abuse and dependence using not only the criminal model but also the medical model.