[Current situation of substance abuse/dependence in psychiatric hospital settings]

Over the last several years, Japan has been facing its third epidemic of methamphetamine abuse. Methamphetamine and MDMA are categorized as Amphetamine Type Stimulants (ATS), and abuse of these substances has become a worldwide problem. A nationwide mental hospital survey on substance-related psychiatric disorders in Japan has been conducted since 1987 to clarify the current situation of Japan's substance abuse and dependence. Recent surveys show that methamphetamine and organic solvents are the most common substances of abuse in hospital settings. Fifty-five percent of all the patients included in the latest study in 2002 had psychiatric disorders due to methamphetamine abuse. Forty-five percent of them were diagnosed as having a psychotic disorder, and twenty-five percent had psychotic episodes lasting over six months. According to the psychotic disorder criteria in ICD-10 (F1x.5), the duration of a psychotic episode must not exceed six months. If the criteria are strictly applied to the abusers, they should not be diagnosed as having a psychotic disorder due to methamphetamine use, but as having schizophrenia or some other delusional disorder. However, the study demonstrates that many psychiatrists in Japan recognize methamphetamine user patients with persistent episodes of psychosis as having psychosis due to the substance use. This may reflect differences of diagnostic viewpoint between operational criterion in English-speaking countries and clinical observation of Japanese psychiatrists. In other words, it may reflect the difference between the acute toxic model and chronic toxic model of substance-induced psychiatric disorders. Reconsidering this point further will be productive and interesting. The latest survey also indicated gender differences in psychiatric disorders related to substance use. It revealed that female patients were likely to have more severe dependence syndromes, co-morbid psychiatric disorders, and a history of traumatic life events. It suggests that the substance-related psychiatric problems in female patients are possibly more complex and harder to treat. Treatment programs that focus more on gender differences in these disorders should be developed.