MMPI interpretation of psychiatric inpatients: caution in making inferences about concentration and memory

The relation of specific MMPI scores to attention, concentration, and memory was assessed in an inpatient psychiatric sample diagnosed by DSM-III-R criteria as having schizophrenia, chronic undifferentiated type (n = 22); schizophrenia, paranoid type (n = 17); and schizoaffective disorder (n = 20). MMPI indices that are used widely to infer cognitive efficiency--including Scales 2 (Depression), 8 (Schizophrenia), SC-PT, D4 (Mental Dullness), SC2A (Lack of Ego Mastery, Cognitive), PSY (Psychoticism) and ORG (Organic Symptoms)--were investigated in relation to actual performance on Digit Span and subtests of the Wechsler Memory Scale (WMS, Russell's Revision). Weak correlations emerged (maximum r = .31, p less than .05), which suggests that scores on these MMPI measures may not provide a reliable basis for inferring attention and memory functioning.