Does ayurveda really treat mental illness?

Too broad a question: There is no single mental illness. There are many mental disorders. More than 2000 years ago ayurvedic physicians in india treated psychosis/ schizophrenia with a plant called rawulfia serpentina. The main chemical of this plant is reserpine. In usa they treated schizophrenia in 50s with reserpine. I will say thet ayurvedic medicine should not be your first choice for major mental disorders.