lol it's completely true. educate yourself:
http://www.ncbi.nlm.nih.gov/pubmed/7408949
"Continuous release of p-chloroamphetamine from subcutaneously implanted minipumps for 3 days decreased brain 5-hydroxytryptamine, but not norepinephrine or dopamine, when analyzed 2 weeks later. In contrast, 2 weeks after infusion of amphetamine, whole brain dopamine but not 5-hydroxytryptamine or norepinephrine, was decreased. Also, the high affinity uptake of [3H] dopamine was markedly and selectively reduced in striatal synaptosomes. Thus, neurotoxicity is apparently not unique to halogenated amphetamine derivatives, but is produced by amphetamine itself if administered continuously."
being a biochemistry/molecular bio major with pharmacology minor at UCSC, and an intern in a chem lab there, i have access to a lot of information regarding drugs. aside from this i'm a former drug addict myself, and my girlfriend is prescribed low dose amphetamines. nobody even challenges the fact that amphetamines cause damage to the dopaminergic system. have you ever seen a meth addict before? case in point... even low doses of non-methylated amphetamines, in the long term, cause changes to the dopamine system. it's hard to say whether it's "good" or "bad" for your brain to change your dopamine and DR levels, but it certainly lowers energy and motivation levels. i'd know because i've been through it. and i've had almost a dozen neurotransmitter tests, before and after, to mark the progress of my supplement regimen.