Recently, the investigators group has conducted a prospective study assessing behavior and psychiatric symptoms in patients undergoing STN stimulation up to one year after surgery. After subthalamic stimulation non-motor fluctuations improved and pathologic hyperdopaminergic syndrome, i.e. behavioral addictions (including pathological gambling, hypersexuality, binge eating, compulsive shopping, …), compulsive use of dopaminergic treatment and dopaminergic dysregulation syndrome (defined as the association of one or more behavioral addictions to compulsive use of dopaminergic treatment), disappeared. These findings represent a milestone because, if confirmed, the indications of STN stimulation might be extended beyond motor complications. To date, there are several long-term studies on motor and cognitive effects of STN stimulation, whereas no long-term longitudinal data on neuropsychiatric effects do exist. Therefore, the investigators designed a long-term prospective study, assessing over 3-8 years behavioral and psychiatric effect in the same cohort of patients included in the one-year study. This study will allow to better evaluate the change in non-motor fluctuations and of behavioral issues in the long-term with a standard management.