BackgroundIndividuals with mood disorders often report lingering health-related quality of life (HRQOL) and social and cognitive impairments even after mood symptoms have improved. Exercise programmes improve mood symptoms in patients, but whether exercise improves functional outcomes in patients with difficult-to-treat mood disorders remains unknown.DesignWe evaluated the impact of a 12-week structured running programme on cognitive, social and quality-of-life outcomes in participants with difficult-to-treat mood disorders.MethodsIn a prospective, open-label study, patients referred to the St Joseph’s Healthcare HamiltonTeam Unbreakablerunning programme for youth and adults with mood disorders completed a comprehensive assessment battery before and after the 12-week exercise intervention.ResultsWe collected preintervention and postintervention data from 18 participants who improved on the general health, vitality, role of emotions, social functioning and mental health (all p≤0.01) HRQOL subscales. Performance improved on cognitive tests that assessed working memory and processing speed (p≤0.04); there were no improvements in complex executive functioning tasks. Regression analyses indicated that younger age, shorter illness duration and reduced bodily pain predicted social and cognitive outcomes.ConclusionParticipation in a group-based, structured running programme was associated with improved HRQOL and social and cognitive function.