Transdiagnostic Cognitive Behavioural Therapy for Emotional Disorders HARRISKELLY ROBYN 2018 Depression and anxiety are commonly occurring mental health disorders that affect a significant proportion of the world's population, impacting not only the individual sufferer but their family, friends and the broader community. Traditionally treatments have targeted either depression or anxiety disorders, however recent evidence suggests greater commonalities than differences among these conditions. The current body of research involves the development and evaluation of a novel transdiagnostic approach for the treatment of depression and anxiety combined.