The quakers figured out that most people could recover from what are now called "psychotic breaks" by being put in a safe place ("asylum") and provided 4 meals a day [2]. Much of the current problems of Psychiatry stem from the split of neurology and psychiatry [0]. Over the last 60+ years investigators have found many physiological considerations for the so-called "mental" disorders. The core of the resistance again…
So the problem here is that our ability to observe physiological differences, particularly given the development of EEG/MRI/CT/etc, has radically outpaced our ability to have any clue what they mean. The point being that just because a "condition" has a physiological manifestation in no way whatsoever then directly implies that the condition is therefore physical or can even be realistically 'treated'. For instance, we're not going to develop a drug to make you a strong chess player anytime in the foreseeable future. And while perhaps you could create a drug to make a master a weak player again, it would almost certainly be little more than a glorified lobotomy.