Yes, it's a metal just like zinc, iron and magnesium are metals and all of which the human body needs to stay healthy. And salt intake effects lithium levels. Lithium treatment was shown to have a positive effect on controlling mania. What's your point?

I believe that Medical Scientists know very little about Mood Disorders but they do know that the brain is extremely complex and works mysteriously.

Alcoholics can eventually grow more receptors on their brain cell synapses that will accept alcohol and the other receptors that accept various other neurotransmitters start to diminish. Consequently, drinkers crave more and more alcohol and become addicted.

And you can't argue with PET Scans that show abnormal brain activity (ie electrical activity) in people that suffer from disorders like OCD. Or even depression for that matter.