Analyses of attention and global behaviors, measured at intervals from about 12 to 26 years of age, indicate (a) attentional deficits can be reliably detected in high-risk children who will develop future schizophrenia-spectrum disorders (the prespectrum [PSP] group); (b) these deficits are stable, enduring over time, and appear to reflect a compromised attentional capacity; (c) attention is not affected by the onset of illness in the PSP group; (d) for all subjects, attention and global behaviors follow independent developmental pathways; and (e) behavioral difficulties, but not attention deficits, appear to be highly sensitive to environmental factors, especially rearing by a mentally ill parent.