Chronic schizophrenia-like states in methamphetamine psychosis.

In order to clarify the characteristic psychopathology of chronic methamphetamine (MAP) psychosis, the clinical symptoms of 11 chronic MAP psychotics were compared with those of the same number of chronic schizophrenics matched for sex and age. The positive symptoms were almost similar in both groups. However, the negative symptoms evaluated by the Scale for the Assessment of Negative Symptoms (SANS) differed considerably. According to the SANS, the scores of avolition-apathy, anhedonia-asociality and attentional impairment were moderately high in both groups. The scores of affective flattening or blunting and alogia were lower in the MAP group than those in the schizophrenia group. The SANS scores of negative symptoms increased in accordance with the age of onset in the MAP group, while such a correlation was not observed in the schizophrenia group. Furthermore, detailed clinical observations of the patients revealed the following differences between the two groups: 1) spontaneous affective expression during the interviews was more vivid in the MAP group compared to the schizophrenia group, and 2) affective expressions or interpersonal behaviors changed immediately depending on the situation in the MAP group. From the viewpoint of clinical psychopathology, a group of MAP psychotics whose hallucinatory-delusional state persisted for a long period of one month or more after cessation of MAP use seemed to differ from either chronic schizophrenics or patients with acute MAP psychosis. The author proposed that this group of patients should be a clinical entity and be called as "residual methamphetamine psychosis."