Does personality change as a result of fetal tissue transplantation in the brain?

This study examined the effects on personality of transplantation of fetal tissue into the brains of participants in a double-blind placebo control trial for the treatment of Parkinson's disease (PD). Thirty persons with PD (equal numbers of males and females) participated in a larger study investigating the efficacy of transplantation of fetal neural tissue versus placebo surgery. Participants were randomly assigned to receive either the fetal transplant or placebo surgery. The blind was lifted for all patients approximately 13 months after surgery, at which time individuals who had received the placebo surgery could choose to receive the transplant surgery. In this study 12 persons originally received the transplant and 18 received placebo surgery. The NEO Five-Factor Inventory (NEO-FFI), a commonly used measure of personality characteristics, was administered to participants at baseline, 12, and 24 months after surgery. Scores at baseline for the Openness and Agreeableness scales were significantly higher for this sample of PD patients than scores for the normative group. There were no changes on any of the five scales from baseline to 12 months for the total group. The only significant change in the original transplant group was a decrease in Conscientiousness from baseline to 24 months. There were no changes over time among the group who had placebo surgery first and then the transplant. Results indicate that personality, as measured by the NEO-FFI, basically remained stable during the two-year follow-up period of this study. In this case, no change is regarded as a positive outcome.