The “moral treatment” movement rapidly declined in the late nineteenth century because:

Moral treatment was an approach to mental disorder based on humane psychosocial care or moral discipline that emerged in the 18th century and came to the fore for much of the 19th century, deriving partly from psychiatry or psychology and partly from religious or moral concerns. The movement is particularly associated with reform and development of the asylum system in Western Europe at that time. well this is how it approach maby this will help :D