Measuring psychiatric disorder in the recent past: the use of the Psychiatric Assessment Schedule retrospectively.

Ninety-four patients were asked about the presence of psychiatric symptoms on admission to hospital using the revised Psychiatric Assessment Schedule. Three months later they were asked to recall their symptoms at admission using the same instrument retrospectively. The results of the initial and retrospective interviews showed good rates of agreement in terms of PAS score, ID level, psychiatric 'caseness' and both CATEGO and DSM-III-R diagnoses. The study demonstrates that it is possible to make reliable measurements of the mental status of three months previously, simultaneously with assessments of current mental status. The uses of such a measuring instrument are discussed.