Lithium for Parkinson's: an Extension Trial

1. All PD patients completing STUDY00007253 or STUDY00008239 at the University at Buffalo will be eligible. 2. No unstable cardiac, medical, neurologic or psychiatric condition in the opinion of the PI. 3. No current use of illicit drugs or current alcohol abuse in the opinion of the PI. 4. No history of brain surgery or possible need for brain surgery including deep brain stimulation (DBS) for at least 24 weeks in the opinion of the PI. 5. Women with child bearing potential will need a negative pregnancy test and not be nursing an infant at screening. Women with child bearing potential will need to report using barrier method or hormonal contraception. 6. Willing and able to sign informed consent and follow study procedures.