Behavioral response to methylphenidate challenge: Influence of early life parental care and personality 1 Behavioral response to methylphenidate challenge: Influence of early life parental care and personality Doctoral Thesis by Veronika Engert Faculty of Psychobiology Department of Clinical and Theoretical Psychobiology University of Trier, Germany Supervisors: Prof. Dr. Dirk H. Hellhammer, University of Trier, Germany Prof. Dr. Jens C. Pruessner, McGill University, Quebec, Canada October 2006