Most "organic brain syndromes" are not difficult to diagnose. However, some "organic" states resemble schizophrenia, and this is particularly true of the acute intermittent type of porphyria. Here, the variable pain and paralysis and the prominent psychic changes can easily lead to errors in diagnosis —as recounted in the cases presented—unless this classical triad is kept in mind as being characteristic of porphyria.Early diagnosis would prevent unnecessary surgery and psychotherapy, the administration of drugs which can precipitate an attack, and even commitment as a schizophrenic. It is likely that there are undiagnosed porphyrics in the present mental hospital population of this country; we should therefore routinely do a Watson test on any patient—especially the young female—who is troubled with unusual abdominal pain and any sort of psychic disorder, with or without any concomitant neurological symptoms being present.Little mention has been made of this disease in the past, because it has been thought to be very rare. However, an average of more than one case a year is seen at our 1,000-bed hospital, and it has often been shown in the past that when attention is focused upon supposedly "rare" diseases they are found to be much more common than previously supposed.Abstract Teaser