Young people with Type 1 Diabetes are a group at special risk. Demanding insulin regimes conflict with changes characteristic of this stage life. Consequently there can be a decrease in motivation to achieve the glycaemic control necessary to avoid the life-limiting complications associated with this chronic illness. This group is at risk of worse physical and mental health compared with the general population, yet little work has focused on improving outcomes in this group. In a first study, we sought to clarify the prevalence of depressive symptoms, anxiety and diabetes-related distress in a sample of young people (16-21 years). Depression and anxiety were found to be comparable to the general population, with elevated depression and diabetes-related distress associated with worse glycaemic control. Diabetes-related distress was found to mediate the relationship between depressive symptoms and glycaemic control. In light of these findings, we conducted a meta-analysis to determine interventions which improve both medical and psychological outcomes in young people with Type 1 Diabetes (study 2). Thirty-four trials were identified. Those interventions incorporating goal setting or focused on the individual were the most effective. These findings were used in order to design an action planning intervention for our target group. The intervention was piloted in Sheffield to determine its feasibility (study 3) and achieved a moderate response rate (66%). The responses were explored qualitatively using content and thematic analysis. A range of goals related to self-management and social life were identified. Barriers to achieving goals and potential sources of support are highlighted. Overall the results support previous work that young people with diabetes are at risk of mental health problems. We conclude that those who report greater diabetes-related distress have worse glycaemic control. Interventions need to be adapted to the specific concerns of young people and address some of the practical difficulties they face related to self-management. An individually based intervention, delivered by a research student appears to have potential to improve HbA1c. Improved success may occur when doctors provide greater back up support and adopt a similar approach to counselling in clinic.