Co-occurring Anxiety and Depression often co-exist when people go through major life events. Both severe anxiety and major depression can mental health disorders. Please refer to the separate sections and Anxiety and Depression Disorders for further information. The Kessler Psychological Distress Scale (K-10) is an effective and scientifically proven self-report scale that measures anxiety and depressive symptoms. It is widely used by general practitioners and psychologists. This demonstrates the prevalence of co-occurring anxiety and depression, particularly in mental illness.