Obstructive sleep apnoea is the most common sleep disorder in general population, and is often associated with cognitive deficit, mood disorders, hypertension, diabetes mellitus, excessive daytime somnolence, nicturia and an increased cardiovascular and metabolic risk. The gold standard of treatment is Continuous Positive Airway Pressure (CPAP), but the adherence is often poor. The aim of our study is to investigate the effort based-decision making in patients with OSA, pre and post CPAP treatment, as a possible cause of poor adherence.