Psychometric validation of psychiatric diagnoses in the New York High-Risk Study

The authors used the Minnesota Multiphase Personality Inventory (MMPI) to provide convergent validity for Research Diagnostic Criteria (RDC) diagnoses of parents with schizophrenia, mainly schizophrenic schizoaffective disorder (SAS), bipolar affective disorder, and unipolar affective disorder in the New York High-Risk Study. Examination of group profiles, as well as univariate and configural analyses of several MMPI variables, led to successful discrimination of the schizophrenic from both affective groups and a normal control group. The results support the validity of risk assessment for children in the study and also suggest that there is commonality between schizophrenia and SAS. Despite variations in clinical status at testing, the MMPI was useful in exploratory analyses to describe phenomenology specific for schizophrenia that was expressed as the predominance of disturbances in thought, social relations, motivation, and affective expressivity relative to a primary disturbance in mood. The results also suggest that there is some symptomatic overlap between schizophrenia and affective disorders regarding a disturbance in social relatedness predominant over a disturbance in mood (for unipolar states) and a disturbance in thought predominant over a disturbance in mood (for bipolar states).