This document discusses the potential role of a health psychologist in the Parkinson's service at Western General Hospital in Edinburgh. It provides an overview of the Parkinson's service and notes two key health behaviors - medication adherence and physical activity - that impact patient outcomes. The document argues that a health psychologist could address these issues by introducing theory-based interventions, like motivational interviewing and cognitive behavioral therapy, to increase medication adherence and physical activity. A health psychologist could also provide training to nurses on these interventions and theories of health behavior.