APA Dictionary of Psychology

a quick screening device used to identify persons who should receive a more extensive mental health evaluation. Designed to be completed in about 15 minutes, the PSI contains 130 true–false items across five scales. Three basic scales include the Alienation (Al) scale, which screens for major psychiatric disorder; the Social Nonconformity (Sn) scale for significant antisocial behavior; and the Discomfort (Di) scale for general psychological distress. The remaining two scales include the Expression (Ex) scale, which assesses the personality dimension of extraversion–introversion, and the Defensiveness (De) scale, which assesses the degree of an individual’s personal defensiveness in responding to the items. [published in 1973 by U.S. psychologist Richard I. Lanyon (1937–  )]