A patient with chronic psychosis and intermittent psychotic misidentification of the Capgras and intermetamorphosis types refractory to neuroleptic treatment was given a trial of clorazepate. Complete remission of psychotic symptoms was achieved for the first time in 19 years, but these recurred when the patient discontinued her clorazepate. It is concluded that clorazepate may be a useful treatment for some cases of chronic psychosis and psychotic misidentification. A possible mechanism for this is discussed.