Daily life memory functioning in familial and nonfamilial schizophrenia : a study of schizophrenic patients and their first-degree relatives

Abstract

Objective: To explore the phenotypic boundaries of the schizophrenia genotype by evaluating daily life memory functioning in schizophrenic patients from multiply and singly affected families, their relatives and normal control subjects. Method: Two groups of schizophrenic patients (familial/nonfamilial), their first-degree relatives (including 10 presumed obligate carriers) and normal controls participated in the study (251 subjects in total). All participants underwent a series of tests including the Rivermead Behavioural Memory Test (RBMT) (Wilson, Cockburn, Baddeley, Hiorns, 1991) which was developed to detect abnormalities associated with daily memory processing. It consists of 11 subtests each selected to assess various practical aspects of daily life. Results: Overall, highly significant RBMT profile mean score differences were found between groups (X2=35.1, df=4+ P<0.0001). Both schizophrenic samples differed significantly from controls (familial vs. controls z=5.01, P<0.0001; nonfamilial vs. controls z=3.96, P<0.0001) amd their relatives (familial vs. relatives z = 5.01, P< 0.0001; non-familial vs. relatives z=3.96, P<0.000I). A non-significant trend was found between presumed obligate carriers and controls (z = 1.83, P= 0.06). No significant differences were found between the rest of the relatives and controls. Conclusion: (1) Schizophrenics show deficit; (2) most of the relatives do not show defect but presumed obligates may.