Methamphetamine is useful for non-self-destructive activities, which is why it is legal by prescription. Medical methamphetamine is used to treat narcolepsy and ADHD. On top of that, pharmaceutical methamphetamine is much safer, even at recreational doses, than black market drugs because the production process is well regulated.
Well actually there is a world of difference between Methamphetamine and Amphetamine (Adderall). They are in the same family like MDMA but the addition of a methyl group makes Methamphetamine a neurotoxin. "Methamphetamine is a potent neurotoxin, shown to cause dopaminergic degeneration."[1] So they although they share same traits, their hazardous effects are no where close to each other.
This is why drugs are complicated and different. Blanketing all "drugs" as bad while drinking Coffee, Whisky and Aspirin is just hypocritcal and dangerous.
Also, as an anecdote, I have received d-amphetamine by prescription and have taken Desoxyn about five times. They're not that different, Desoxyn is subjectively 'cleaner'.
I stick to caffeine though, and roughly half a Modafinil every two weeks. Amphetamine is just not my friend. Your mileage may vary.
I am aware of the difference between methamphetamine and amphetamine, but the reality is that methamphetamine is used medically and that in small doses the harm is below the measurement threshold. I do not doubt that harm is caused at recreational doses, but vastly more harm is caused by the adulterants in black market methamphetamine.
