[Deep brain stimulation, Parkinson's disease and neuropsychiatric complications].

Bilateral high-frequency stimulation of the subthalamic nuclei is now considered as the method of choice for the treatment of severe and advanced forms of Parkinson's disease. The technique improves patients' quality of life, disability, motor complications and allows the dose of dopaminergic treatment to be reduced. The dramatic motor benefits provided by the technique were firstly accompanied by a number of psychiatric complications--depression hypomania or mania, anxiety disorders or behavioural disorders--reflecting both the deleterious effect of modulation of the limbic circuit and the (inappropriate) selection of patients with past history of severe psychiatric disorders. Following a number of prospective studies, it is now considered that the rate of severe psychiatric side effects induced by deep brain stimulation is low, provided that the patients are well selected, the electrodes adequately placed and the postoperative follow-up appropriately performed. Interestingly, the favourable effects of the technique on both anxiety disorders (particularly obsessive compulsive disorders) and some behavioural disorders (mainly repetitive behaviour), strongly suggests that deep brain stimulation-associated modulation of associative and limbic circuits--through the basal ganglia--might be the method of choice for the future treatment of severe and medically refractory neuropsychiatric disorders such as Tourette's syndrome, obsessive compulsive disorders and addiction disorders.