Were the asylums of the nineteenth century intended to incarcerate dangerous elements of society or treat unfortunate sufferers?

It is a reasonable assumption that throughout mankinds history mental illness has been present.  Ancient sources exist detailing the mannerisms and symptoms of mania and melancholia, diseases that could today be identified as schizophrenia and depression.  The mad were often left to themselves, the village idiot being a common sight in English villages throughout the middle ages.  During the seventeenth century, dangerous mad people would be incarcerated in prisons and privately run madhouses whilst those who could not support themselves would often be grouped together with other social deviants in the workhouses….(short extract)