'Scientists' began to give names to medical issues delving into the physical and mental locations and chemistries and causes.   

But the problem is SIN.   Original sin and my sin.   

All sickness and disease is a result of sin.   All human birth defects and imperfections are a result of sin.   

Jesus ( Mighty God) came to heal us first and foremost of the sin which separated us from Him and secondly to provide a way for the residual damage of that sin in the human genome to be reversed - healed.   However, He only made provision for reconciliation and healing.   He did not implement reconciliation nor healing impersonally and globally.   
His provision for both demands that we draw near to Him.   

We must hear the Gospel, believe the Gospel, receive the Gospel and do the Gospel.   
We 'do' the Gospel when we repent and turn to Christ as our Lord, our Savior and our Healer.   

We make our faith substance and evidence by a transformed life which He implements in our spirit but we must implement in our soul by immersing ourselves in His Word and immersing ourselves into His Spirit.   

As to the mentally ill?   I submit that every person who has not been born again is mentally ill.   

How society determines mental illness is arbitrary.   

As a matter of fact, those on the left who hate Christ and Christians consider Christians to be mentally ill.   As a person who lives 'on the grid', I see people who live 'off the grid' as mentally ill.   I suppose they in turn see people who live 'on the grid' as mentally ill.   

The thief does not see himself as mentally ill.   He is simply trying to get along.   It is likely that he looks at people who work for a living as mentally ill - suckers.   

The point I am trying to make is that apart from God we are lost.   We are incapable of agreeing on what is normal and what is not, what is acceptable and what is not, what should be punished and what should be condoned.   

What is the treatment for the mentally ill?   To be set free and to be healed.   

All mentally ill people are in bondage to something.   That bondage results in ills that plague humanity.   

This is why Christ Jesus commanded His followers to preach the Gospel to every creature - so that they could be set free, healed and experience eternal, abundant life.   

To preach is to proclaim.   The Gospel is words but those words are the Word Of God and there is power in those Words to set the captive free, to heal and to produce life.   But only to those who receive those Words.