Event-related potentials were recorded for childhood- and adult-onset schizophrenia subjects performing the span of apprehension (Span) task, which is sensitive to vulnerability factors in schizophrenia. Subjects responded to the onset of the Span arrays in a reaction time condition and then responded differentially to the presence of one of two target letters in the Span condition. While neither the childhood- nor the adult-onset group exhibited abnormalities in preparatory contingent negative variation activity, both groups produced significantly less endogenous negative activity between 100 and 300 ms after Span stimulus onset than age-matched normals. This endogenous negative activity reflects attentional effort associated with serial search and stimulus identification. These results support the position that schizophrenia subjects are impaired in their ability to allocate adequate attentional resources for processing Span stimuli. Moreover, the similarity of this information-processing deficit in the two groups suggests that childhood- and adult-onset schizophrenia lie on a continuum in this regard.