Psychiatric Diagnoses: A Study of How They are Made

¹ Reader in Psychiatry, The Institute of Psychiatry, De Crespigny Park, London, SE5 8AF

Brief diagnostic interviews, lasting only five minutes each, were held with a series of 28 patients at the time of their admission to hospital and then presented to groups of experienced psychiatrists who were required to make a diagnosis and a number of other ratings for each. The content of the interview was presented in three alternative ways—as a videotape, as an audiotape, or as a written transcript.

The raters' diagnoses were the same as the final hospital diagnosis in 48-50 per cent of cases after only the first two minutes of the interview, and this rose to 60-64 per cent at five minutes. Inter-rater agreement was over 75 per cent under all three rating conditions. Using the final hospital diagnosis as a criterion of accuracy, both accuracy and inter-rater agreement were just as good overall using the soundtrack alone, or even the transcript, as with the full videotape, in spite of the fact that the transcript conveyed no information about the patient's appearance or behaviour.

There was little variation amongst the 28 psychiatrists involved. No one achieved a diagnostic accuracy of more than 71 per cent or less than 50 per cent, or was particularly prone, or reluctant, to change his initial diagnosis. Nor was there any relationship between accuracy and either length of experience or self-confidence.

Diagnoses made by adequately trained psychiatrists are more reliable than the literature would indicate. In many patients an accurate diagnosis can be made within the first few minutes of an interview and behavioural cues seem to be of little or no importance in this regard.