DMT detectable by our method was seen more frequently in the urine of psychiatric patients than normal subjects and most often in the urine of psychotic patients. Nevertheless, the presence of detectable DMT is not exclusively related to psychosis, since it was also found in the urine of people who had never been psychotic. Furthermore, patients with affective psychosis were no more likely to excrete measurable quantities of DMT than those with neurotic reactions and personality disorders.