A comparison of psychiatric and psychological assessments of acute schizophrenics

Abstract

Psychiatric and psychological ratings of psychopathology were compared by means of canonical correlation of scores on the Inpatient Multidimensional Psychiatric Scale (IMPS) syndromes with scores on the 10 subtests of the Structured Clinical Interview (SCI). The ratings by a team of psychologists on the SCI and by a team of psychiatrists on the IMPS were made simultaneously, while one of the psychologists conducted the structured interview of the SCI. In this way, 72 acute schizophrenics were rated shortly after admission to a psychiatric hospital; 58 of them were re-rated approximately one month later in a replication of the original procedure. Two canonical analyses were carried out: one on the initial ratings, the second on the replication. Canonical correlations of .84 and .86 were obtained respectively for the first latent roots at each occasion. Successive significant roots yielded correlations of .78 and .68 on the initial ratings and .76, .69, and .64 on the follow-up ratings. After all 10 latent roots had been extracted for each occasion of rating, redundancy coefficients were calculated for each instrument. The results showed that for the initial ratings 30% of each instrument’s variance could be explained by the other instrument; at the follow-up ratings the redundancies were 40% for both sets of variables. The data are interpreted as evidence for the congruent validity of the SCI.