Several Clinical studies have shown specific Temperament and Character Profiles in adult ADHD patients. In all studies drug naive patients were included.

The present study was set up to assess whether adult ADHD patients referred to an outpatient clinic would show altered temperament and character profiles after they were put on psychostimulant medication.

During 18 months patients were recruited randomly from two out patient Clinics in Western Brabant, The Netherlands. ADHD symptoms were rated with the ASRS-Dutch version and temperament and character with the VTCI, a shortened Dutch translation of the TCI. Patients were assessed just before the first prescription of psychostimulants (T0) and after subjective clinical effect of the medication (T1).

48 patients gave informed consent and in total 38 completed the study. Significant differences between T1 and T0 were found for Novelty Seeking, Harm Avoidance, Self- Directedness and Self-Transcendence.

Adult ADHD patients can experience significant differences in temperament and character profiles after taking psychostimulant medication, suggesting different attitudes in daily life like carefulness, resilience, selfimage and sense of belonging are encouraged. It is important to discuss these issues with ADHD patients.