John Cullen was diagnosed with Parkinson's disease in 2015 at age 56. As the son of a U.S. Marine Corps colonel, Cullen maintains a warrior mindset and faces his adversity with grit, courage, and humor. In 2019 he created his mantra, "It's Just Parkinson's" (IJP), the philosophy he uses as he battles this incurable disease. This mindset later led to the feature-length documentary It's Just Parkinson's. In Unbreakable,...