Reliabilities and intercorrelations of eight measures of proneness to psychosis.

Abstract

Scales thought to measure psychosis proneness-Eysenck and Eysenck's Psychoticism Scale, Golden and Meehl's Schizoidia Scale, composite scales for the Minnesota Multiphasic Personality Inventory (MMPI) 2-7-8 and 2-7-8-6 profiles, and our own research project's Physical Anhedonia, Perceptual Aberration, Magical Ideation, and Nonconformity scales-were compared on their coefficient-alpha estimate of reliability and were intercorrelated, using samples of college students (Ate = 5,567, 1,510 and 537) and outpatient clinic clients (Ns = 120 and 220). Test-retest reliability was examined for five of the scales using 511 college students. The Psychoticism and Nonconformity scales were found to measure the same pathology, but the Nonconformity Scale did so more reliably. The Schizoidia Scale was found to measure the same pathology as the MMPI 2-7-8 and 2-7-8-0 scales, but the longer MMPI scales did so more reliably. The Magical Ideation and Perceptual Aberration scales were highly correlated, and both had a negative correlation with the Physical Anhedonia Scale. The MMPI 2-7-8 and 2-7-8-0 scales correlated positively with all of the other,scales, indicating that these MMPI composite scales are sensitive to more than one kind ' of pathology.A number of true-false scales and scale profiles have been developed in an attempt to measure proneness to psychosis in general and to schizophrenia in particular. The measures of interest in the present report are scales representing the Minnesota Multiphasic Personality Inventory (MMPI)

The dimensional structure of the Wisconsin schizotypy scales: Factor identification and construct validity

“…Contrary to previous recommendations, 43 raw scores on the schizotypy scales (rather than scores normed on sex and ethnicity) were used for the subsequent analyses-given the minimal effect of these variables on the schizotypy scores. 44 the Perceptual Aberration and Magical Ideation Scales were highly correlated, as were the Social Anhedonia and Physical Anhedonia scales. The Physical Anhedonia Scale was not correlated with Perceptual Aberration or Magical Ideation scores.…”

Understanding Predisposition to Schizophrenia: Toward Intervention and Prevention

“…First, we recently obtained concurrent validation of schizotaxia by comparing subjects who met our criteria for schizotaxia with those who did not on independent measures of clinical function (67). These measures included the DSM-IV Global Assessment of Functioning Scale (GAF) (68), the Social Adjustment Scale (SAS) (69), the Symptom Checklist-90-R (SCL-90-R) (70), and Chapman's Physical Anhedonia Scale (PAS) (71). On each of these scales, the schizotaxia subjects showed poorer clinical or social function, regardless of whether they were rated by the subjects themselves or by the investigators (blindly).…”

A Ten-Year Longitudinal Study of Intense Ambivalence as a Predictor of Risk for Psychopathology

“…The Perceptual Aberration and Magical Ideation Scales have good to excellent internal consistency (coefficient alpha of .82 to .89). These two scales are highly correlated in college student samples (.70) and therefore high-scoring subjects are typically assigned to a single Per-Mag group (Chapman et al, 1982). The Intense Ambivalence Scale and the Perceptual Aberration Scale correlate .38 in male college students and .47 in female college students (Raulin, 1984), suggesting that the Intense Ambivalence Scale captures some unique variance that is not accounted for by the Perceptual Aberration Scale.…”