Side rant:
Claiming that you don't believe in God is equally annoying as those sect guys knocking at your door. I do believe in God and I find the use of lithium in treating these illnesses a hope (with potential dead serious side effects: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4456600/) but not the potential meaning of life (?! how can you compare lithium with the notion of God?!).