Parkinson’s disease (PD) is a devastating, progressive disorder that responds favorably to therapeutic doses of levodopa, its gold standard therapy. The phase of the disease (early, middle, or advanced) largely determines the type of treatment. Initially, there is good response to medication and adjuvant therapeutic strategies but, after several years, motor and non-motor complications develop. These are produced in part owing to erratic gastric emptying, leading to irregular absorption and fluctuating plasma levels of levodopa, and hence an unstable response. At this point, clinical fluctuations are gradually more difficult to control and, therefore, patients’ quality of life deteriorates. In recent years, the development of subthalamic and pallidal deep brain stimulation (DBS) for the treatment of these long-term PD complications has been a major step forward. There is good evidence that DBS can reduce the difference between off and on states and that the benefit achievable with DBS can be predicted by the levodopa response. Nevertheless, the clinical reality is that DBS does not reach the theoretical maximum effect in everyone. Patient selection and electrode location have a huge impact on the outcome, as does the experience of the surgeon. Adverse effects derived from the neurosurgical procedure are uncommon, but the so-called hardware complications produced by fractures, disruptions, or infections of the implanted system are relatively frequent. Psychiatric symptoms after subthalamic stimulation have also been repeatedly described in the medical literature. Moreover, a recent study demonstrated that only about 1.6–4.5% of patients are suitable for DBS.¹