THE KRAEPELINIAN^1,2 binary system, it may be said, is dead, but the tyranny of its influence lives on. Notwithstanding a series of critical evaluations,^3-6 it pervades textbooks, examinations, and every set of operational diagnostic criteria. Late in life, Kraepelin tried to get the genie back into the bottle:

No experienced psychiatrist will deny there is an alarmingly large number of cases in which it seems impossible, in spite of the most careful observation, to make a firm diagnosis . . . it is becoming increasingly clear that we cannot distinguish satisfactorily between these two illnesses and this brings home the suspicion that our formulation of the problem may be incorrect.⁷