The relationship between depression and mental quality-of-life outcomes. HRQoL. Depression is defined as a reported BDI score of ≥14 or a BDI score of <14 while actively receiving therapy for depression. No depression is defined as a BDI score <14. Moderate depression is defined as a BDI score of 14 to 25. Severe depression is defined as a BDI score of 26 to 63.