In the very study you post, it says outright that cocaine is not neurotoxic (which begs the question of why it's illegal).
Meth is laso not the same as adderall or dexedrine, though. Meth is much stronger and causes a lot of neurotoxicity. You use a lot smaller doses therapeutically, but ultimately for therapetic uses stimulants are stimulants. There's about 1 mg of cocaine in each bag of tea, and it absorbs over a couple of hours or so. It's fairly helpful, though not as good as taking an adderall, but then nothing is.
From what I've read it's basically the transportation of dopamine to the receptor sites that kills off the receptors. Cocaine doesn't do that (which is why it's munch less helpfull than amphetamines and doesn't cause neurotoxicity). Basically, if you are feeling intense euphoria with amphetamines that's the feeling of your brain cooking itself off. If you are not getting that intense euphoria then it seems you are not getting any neurotoxicity. Smart people come to realize quick that the euphoria is not what means it's working (and really, I've never gotten any, anyway). I get a brightened mood, but not what other people seem to get out of it.
FunkyOddesy - Nicotine is extremely effective, but it has bad side effects of vasoconstriction and at higher doses, nausea, manickiness, and irritability. When I was using it for 3-4 months (along with wellbutrin and occasional adderall) it was enough to completely halt my ADD 24 hours a day.
The study you selected out of several citations states that cocaine is not neurotoxic to dopamine and serotonin neurons. This is not the same thing as saying Cocaine is not neurotoxic. Cocaine IS neurotoxic to specific cells in two other transmitter systems, acetylcholine and gamma-aminobutyric acid. Even more fun, cocaine is extremely toxic to cells in your Fasciculus retroflexus. This is one of the primary contributing centers for self-control. Cocaine has other neurotoxic effects as well. Read the monograph I selected or just google "Cocaine neurotoxicity". Cocaine wrecks your brain, end of story.
As for dextroamphetamine: Results show that a single injection of a high dose of AMPH is able to induce several neurotoxic effects. I believe the most consistent finding for therapeutic doses of D-AMPH is a change in dopaminergic nerve terminal morphology and a reduction in synaptic DAT proteins. Only in extraordinary high doses does one begin to see actual apoptosis of dopamine neurons. It also causes an increase in oxidative stress in blood and tissues, causes cardiovascular stress, hyperthermia, etc. Hypertensive crisis has been reported even at therapeutic doses, and this is because individual responses to dex vary dramatically, and any or all of these effects may come into play at "regular therapeutic dosages" in some individuals.
Hopefully we are agreed that Methamphetamine is highly neurotoxic, primarily due to its serotonergic effects and greater potency.
It never fails to amaze me how far people will go into self-delusion and/or deluding others to defend drugs of abuse in spite of reality.