Stability in MMPI among adoptees with high and low genetic risk for schizophrenia and with low Communication Deviance of their adoptive parents.

Stability has been considered an important aspect of vulnerability to schizophrenia. The temporal stability of the scales in the Minnesota Multiphasic Personality Inventory (MMPI) was examined, using adoptees from the Finnish Adoptive Family Study of Schizophrenia. Adoptees who were high-risk (HR) offspring of biological mothers having a schizophrenia spectrum disorder (n=28) and low-risk (LR) controls (n=46) were evaluated using 15 MMPI scales at the initial assessment (HR, mean age 24 years; LR, mean age 23 years) and at the follow-up assessment after a mean interval of 11 years. Stability of the MMPI scales was also assessed in the groups of adoptees, assigned according to the adoptive parents'(n=44) communication style using Communication Deviance (CD) scale as an environmental factor. Initial Lie, Frequency, Correction, Psychopathic Deviate, Schizophrenia, Manifest Hostility, Hypomania, Phobias, Psychoticism, Religious Fundamentalism, Social Maladjustment, Paranoid Schizophrenia, Golden-Meehl Indicators, Schizophrenia Proneness and 8-6 scale scores significantly predicted the MMPI scores at the follow-up assessment indicating stability in the characteristics of thinking, affective expression, social relatedness and volition. Low CD in the family had an effect on the stabilization of personality traits such as social withdrawal and restricted affectivity assessed by Correction and Hostility.