Amphetamines are well known to induce mania, which is one reason they are no longer used, as there were formerly used, to treat depression.

I'd like to see some medical references for the statement "amphetamines don't cause brain damage," because study of long-term neurotoxicity or neuroprotective effects of most medicines is still in very early stages. What medical journal references can you cite on that point for amphetamines?

Look at Paul Erdős.