Deep brain stimulation (DBS) is an established treatment for Parkinson’s disease (PD). The success of DBS is highly dependent on electrode location and electrical parameter settings. In this study patient-specific computer models of DBS were used for postoperative follow-up in three PD patients who suffered from stimulation induced hypomania, dysarthria, and uncontrollable laughter respectively. The overall aim of the study was to relate the anatomical aspect of the electric field to the effects and side effects of stimulation. The simulations showed the anatomical distribution of the electric field for all the patients and the results were in agreement with previous reports regarding these side effects of stimulation. It was demonstrated that patient-specific models and simulations of DBS may be useful for postoperative follow-up of DBS.