Author contributions
TPF, CH, GB, CJAM and HVC designed the study. TPF and CH coordinated the trial. HVC supervised the trial, and AM was responsible for medical supervision of the trial. GB wrote the randomisation code. TPF, CH and NDCS did assessments and delivered motivational interviewing. NDCS, TPF and RL handled database management. DYHH conducted the statistical analysis and wrote the first draft of the manuscript with supervision from TPF. All authors critically revised the manuscript.