Drug Induced Psychosis

CLAREBRABBINS Differential diagnosis of psychotic disorder in the young routinelyincludesoe ? Drug inducedpsychosis. Hitherto this diagnostic category has had no consistent definition and the relationship between drug use and psychotic symptoms is controversial. Drug use is a major complicating factor in psychosis, rendersthe managementof psychoticdisordersmore difficult, and adversereactionsto recreationaldrugs may mimic psychosis. We have collected data suggesting that psychiatrists of all grades lack clarity in their understanding of the relationship between psychosis and drug use (Brabbins & Poole, in preparation). The confusion may have its origin in personal experience; the sub-culture of drug use is alien to most psychiatrists, who rarely have had first-handexperienceof it. The sub-cultureof alcohol abuse, on the other hand, is more apposite and familiar. There is no such confusion about the adverse effects of this. The consequences of mis-diagnosis are serious, whether a functional psychosis is mistaken for a drug reaction or vice versa. The inquiry into the case of Christopher Clunis (Ritchie et a!, 1994) drew attention to a number of failings in good practice as a consequence of which a man with schizophrenia did not receivesatisfactory treatment, and went on to kill. Among the errorsidentified was the uncritical attribution of his psychotic symptoms to drug use. Although such tragediesare rare, the diagnostic error is common. In order to understand the various abnormal mental states related to drug use a rational and generally accepted framework is necessary, but there are several obstructions to clarity. Patterns of drug taking alter rapidly with changing fashions, drug availability and shifting sub-cultural values (Wright & Pearl, 1995). Drugs which were virtually unknown in British society until recently, such as free base cocaine (crack) and 3,4-methylenedioxymeth