Refining behavioral phenotypes: Personality-motivation in Williams and Prader-Willi syndromes

Despite behavioral differences, individuals with Williams or Prader-Willi s yndrome share a proneness to certain personality characteristics. We hypoth esized that there are qualitative differences in these shared personality f eatures. Personality-motivation (measured using the Reiss Profiles) was com pared for equal numbers of age- and gender-matched individuals with William s or Prader-Willi syndrome or mental retardation due to nonspecific causes. Each syndrome featured aberrant motivational profiles, and similarities we re found across groups in various domains. Significant differences emerged in the specific stimuli that motivated behavior in several Reiss Profile do mains. Implications are discussed for the "classic" sociable personality in Williams syndrome and for compulsivity in Prader-Willi syndrome. Recommend ations are made for treatment and more refined phenotypic research.