MMPI vulnerability indicators for schizophrenia and attention deficit disorder: UCLA family study of biological parents of offspring with childhood-onset schizophrenia or ADHD

Minnesota Multiphasic Personality Inventory (MMPI) scores were examined for 50 parents of children with an onset of schizophrenia prior to 14 years of age, 153 parents of children with attention deficit hyperactivity disorder (ADHD), and 168 parents of community comparison children. The parents were participants in the UCLA Family Study. The mean scores on all standard MMPI scales were within normal limits for all three groups of participants. Parents of schizophrenia probands were significantly higher on scale Sc than parents of community comparison children. Previous research has shown that scale Sc may be associated with a genetic liability to developing schizophrenia. Thus, scale Sc shows promise as an indicator of a heightened risk for the development of schizophrenia. The parents of the ADHD probands were significantly higher on standard clinical scale Pd than community comparison parents. Mothers of both schizophrenia and ADHD probands shared some personality indicators of stress reactivity. Although this study, like all non-adoptee family studies, cannot disentangle genetic effects on the development of these personality characteristics from environmental effects, we speculate that the emotional distress resulting in higher levels of the MMPI characteristics seen in the patients' mothers reflects the impact of raising a psychiatrically ill offspring.