**Low Voltage Electrical Stimulation for Depression in Parkinson's Patients** Transcranial Direct Current Stimulation (TDCS) is a type of low voltage electrical stimulation applied to the head. This study uses a special version, called mgTDCS, to see if it can help reduce depression in people with Parkinson's Disease (PD). Depression is feeling very sad or not interested in things, while apathy is a lack of feeling or interest, common in PD. This study will involve comparing mgTDCS with a fake treatment (sham) to check if it really works. Participants will have 15 sessions, each lasting 46 minutes, spread over 4-5 weeks. They will complete questionnaires, undergo brain wave (eeg) tests, and take memory tests before and after the treatment. **Key Points:** - Participants will attend 15 sessions over 4-5 weeks. - Participants will complete questionnaires and memory tests. - Study involves comparing real treatment to a fake one to measure effectiveness. Eligible participants are aged 19-65, have PD, and a high score on the Beck Depression Inventory. They must understand English and be able to travel for sessions. Those with epilepsy or certain head injuries are not eligible.