OR THE past 30 years vocabulary performance, used as a measure of former intelligence level, has played a prominent role in the assessment of intellectual deterioration. In recent years, however, the use of vocabulary measures in this manner has provoked a barrage of criticisms (see Yates, 1956, for a comprehensive review). Foremost among these criticisms, as they apply to deterioration in schizophrenics, has been the contention that vocabulary performance also is impaired in schizophrenics, and, hence, cannot be used as a so-called "stable baseline" from which to judge deterioration in other abilities.Impairment of vocabulary performance in schizophrenics, if present, could be manifested as a decline coincident with and a function of the psychotic episode itself, or as a gradual erosion with continued illness and institutionalization, or both. In an earlier investigation (Moran, 1953) the first possibility was examined in a cross-sectional study of 40 matched pairs of schizophrenic and normal subjects (5s). It was concluded that ". . .although the schizophrenic may appear to 'define' words as adequately as the control subject, he is less able than the control subject to attain the 'more difficult solutions' of further differentiating the word meanings, or to use the same words in reasoning or in communicating" (p. 16).The present study reports the results of a 1 This study was made possible by a grant from The Hogg Foundation for Mental Health, University of Texas. Grateful appreciation is expressed to Ruth M. Hubbard and other members of the Waco VAH staff for their cooperation in carrying out this study.