The prevalence of psychiatric comorbidity in Parkinson's disease (PD) is about 50%.The authors investigated differences among PD patients treated by deep brain stimulation (DBS), by drugs alone (noDBS), and healthy control subjects.Samples of 22 subjects in each group were assessed with the Temperament and Character Inventory (TCI) and Hamilton scales for anxiety and depression (Ham–A and Ham–D).Higher scores emerged on two Novelty-Seeking subscales in PD–DBS patients. Ham–A and Ham–D scores were lower in PD–DBS patients than in PD–noDBS patients and control subjects. Rigidity and non-impulsiveness were lower in PD–DBS than in PD–noDBS patients.Further studies should investigate whether or not these changes in personality are a consequence of the motor and depression improvement after DBS.