Parkinson’s disease is a progressive, degenerative neurological disorder. It causes loss of the brain and nerve cells that produce dopamine, the chemical that controls movement and helps balance sleep, wake, and mood cycles. This disruption of signals throughout the central nervous system results in severe tremors, muscle spasms, sleep and mood disturbances, and widespread loss of coordination. Over time, patients have difficulty standing, walking, speaking, and swallowing. Anxiety and depression are also common in Parkinson’s.