Estimation of Premorbid Intelligence in Schizophrenia

Abstract

To determine whether the National Adult Reading Test (NART) would provide a valid estimate of premorbid intelligence in schizophrenia, two schizophrenic samples were recruited, one consisting of 35 patients resident in long-stay wards, the other of 29 patients normally resident in the community. Schizophrenic patients were individually matched for age, sex, and education with a healthy, normal subject. Both schizophrenic samples scored significantly lower on the Wechsler Adult Intelligence Scale (WAIS) than their respective control groups. NART-estimated IQ did not differ significantly between the community-resident schizophrenics and their controls, suggesting that the NART provides a valid means of estimating premorbid intelligence in such a population. NART-estimated IQ was significantly lower in the long-stay sample than in their controls. Although low NART scores in this latter sample could be a valid reflection of low premorbid IQ, the alternative explanation that NART performance was impaired by onset of the disease cannot be ruled out.

Storage and Access Procedures in Schizophrenia: Evidence for a Two Phase Model of Lexical Impairment

“…The NART was developed as a measure for estimating premorbid intelligence in patient groups (for a review, see O'Carroll, 1995) and is viewed as providing a good estimate of premorbid IQ because it: (a) predicts much of the variance in current WAIS IQ; (b) has high reliability in normal subjects; (c) is resistant to cerebral dysfunction (Nelson & Willison, 1991). The NART appears to provide a valid and reliable estimate of premorbid IQ in patients with schizophrenia (Crawford, Besson, Bremner, Ebmeier, Cochrane, & Kirkwood, 1992;Kondel, Mortimer, Leeson, Laws & Hirsch, 2003).…”

Structural brain abnormalities in male schizophrenics reflect fronto-temporal dissociation

“…In any case, age was controlled for in the relevant analyses. Lower NART scores and fewer years of education in the patient group may be a consequence of the pre-morbid cognitive deficits intrinsic to the condition (Jones et al 1994) or subsequent cognitive deterioration (Crawford et al 1992).…”

Is adaptation of the Word Accentuation Test of Premorbid Intelligence necessary for use among older, Spanish-speaking immigrants in the United States?

“…This ensures that individuals can only pronounce the words because they have prior familiarity with them and not by applying pronunciation rules. This is how English words were chosen for the various British versions of the NART (Crawford, 1990(Crawford, , 1992Nelson, 1982;Nelson & O'Connell, 1978) and the versions adapted for Canada and the United States (Blair & Spreen, 1989;Grober & Sliwinski, 1991, Schwartz & Saffran, 1987. The same procedure must be followed in languages other than English.…”