Attention, cognition, and motor perseveration in adolescents at genetic risk for schizophrenia and control subjects

Twenty-three offspring of schizophrenic parents (mean age = 12.1 years, SD = 3.2) and 61 adolescent control subjects (mean age = 12.3 years, SD = 3.3) were compared in their performance of the following psychometric tests: simple reaction times (RTs), warned RTs in a monomodal and cross-modal design, d2 concentration test, a motor perseveration test, and a cognitive performance measure (Wechsler Intelligence Scale). The results were validated in a second analysis in which a subgroup of the control subjects were matched to the high-risk subjects for the following characteristics: age, gender, education, and environmental background. Significant deficits were found in the high-risk group in tests that required sustained attention and information processing under high perceptual load (RT measures and d2 concentration test). Deficits were particularly prominent for the processing of visual stimuli; sensory incongruence might also have been a contributor to this deficit. The attentional dysfunction of high-risk subjects might explain their tendency to show less structured behavior and distractibility as reflected by their higher entropy scores in a motor perseveration test. Cognitive evaluation showed a significant deficit in the high-risk group, primarily as reflected in the verbal IQ score.