> What sort of effects would these drugs give a 14 yr old child with no mental health issues...

Different adults respond differently to different medications, I expect the same rule would apply to adolescents and children.

I don't imagine studies have been done on giving a 14 year old adolescent with no mental health issues a cocktail of medications 'just to see what would happen' so it would be very hard to say...

Are you saying that this adolescent has been prescribed those medications even though the prescribing clinician thought that the person had no mental health issues?

Or are you saying that you don't think the person has mental health issues?

> The side affects were severe. The placid child with no mental history nor violence or criminal history turned violent within weeks, severe personality change, dizziness, aches and pains every day, kidney pain, no urine for days, hillucinations and the list goes on.

Why were they prescribed those medications if they were a 'placid child with no mental history nor violence or criminal history'?

> If a 14 yr old is on 20mg valium 4 times a day is that excesive?

Depends what the 14 yr old is being prescribed the valium for.