Background. Finding risk indicators for schizophrenia among groups of individuals at high genetic
risk for the disorder, has been the driving force of the high risk paradigm. The current study
describes the preliminary results of a neuropsychological assessment battery conducted on the first
50% of subjects from the Edinburgh High Risk Study.
Methods. One hundred and four high risk subjects and 33 normal controls, age and sex matched,
were given a neuropsychological assessment battery. The areas of function assessed and reported
here include intellectual function, executive function, perceptual motor speed, mental control/encoding,
verbal ability and language, learning and memory measures, and handedness.
Results. The high risk subjects performed significantly more poorly than the control subjects in the
following domains of neuropsychological function: intellectual function, executive function, mental
control/encoding and learning, and memory. Controlling for IQ, high risk subjects made
significantly more errors on the Hayling Sentence Completion Test (HSCT), took longer to complete
section A of the HSCT, had lower scores on the delayed recall condition of the visual reproductions
subtest of the Wechsler Memory Scale-Revised, and had significantly poorer Rivermead
Behavioural Memory Test (RBMT) standardized scores. The presence of significant group by IQ
interactions for the RBMT and time to complete section A of the HSCT suggested that differences
among the groups were more marked in the lower IQ range. Performance on the HSCT was found
to be related to the degree of family history of schizophrenia.
Conclusions. High risk subjects performed more poorly than controls on all tests of intellectual
function and on aspects of executive function and memory.