The adolescent psychoses are amongst the most rewarding subjects for study in all psychiatry, not only on account of the considerable clinical interest of these patients, but because no other group affords the psychiatrist quite such an advantage by reason of age alone, an age that covers the peak phase in maturation. The juvenile is young enough for childhood environment to be vividly recalled, the responses to the stresses of puberty are already evident, and in a short space of time the writing of the future adult life pattern will be on the wall. Furthermore, owing to the more likely presence of parents or guardians, sometimes lost or dead by the time one deals with adult disorders, a more comprehensive view of the hereditary influences, and a relatively adequate account of the early formative years, is generally possible.