A patient whom I had known and treated for almost a decade barged into my consultation room one morning while I was talking to my first patient of the day. He flung the door open and blurted to me and my startled patient that he was hearing voices, and just as abruptly and before I could respond, he shut the door on us.

In all these years, this patient, fairly big and in his 30s, had been unfailingly polite, soft-spoken, and mild-mannered to the point of meekness, but that morning I knew with dismay that he had suffered a relapse of his schizophrenic illness and was in the grip of some distressing psychotic experiences.