Clinical status of at-risk individuals 5 years later: Further validation of the psychometric high-risk strategy

The authors hypothesized that at-risk individuals identified on the basis of their Chapman scale scores would be diagnosed with schizophrenia-spectrum disorders at follow-up. In the present study, the authors interviewed 135 young adults approximately 5 years following their initial assessment. The at-risk groups included high scorers on the Perceptual Aberration and/or Magical Ideation Scales (n = 59) and high scorers on the revised Social Anhedonia Scale (n = 32). The control participants (n = 44) scored below 0.5 SD of the same-sex group means on all the scales. At the follow-up, the groups differed in terms of their likelihood of having a schizophrenia-spectrum diagnosis, X-2(2) = 9.79, p < .01. The at-risk groups reported more frequent and severe psychotic-like experiences relative to the control group. These findings support the predictive validity of the Chapman psychosis-proneness scales and may enhance the power of early detection efforts.