Hi Govind, I think that's a good question...I think there are a lot of factors to consider...nature of mental illness for one. I work with clients with different diagnoses of mental illness and use asanas as a complimentary treatment. The more clients I treat though, the more I see we as humans all have some mental illness to some degree or another...I can humbly say I don't know what mental illness is anymore!! Lol! Best, Chard