Adherence to recommended cancer treatments is essential to optimal outcomes. The complex and uncertain nature that accompanies many aspects of the cancer experience is a common challenge. As one patient expressed, “it’s like approaching the edge of a cliff”. Psychological concerns such as distress, depression and anxiety can be precipitated by a cancer experience or may be longstanding. Importantly, poor treatment adherence can be associated with some of the behaviours and beliefs that typically maintain anxiety and depression. This presentation will draw on case examples to demonstrate how contemporary psychological theories allow us to understand and intervene when depression, anxiety, and associated beliefs are barriers to cancer treatment adherence.