Lisdexamfetamine is not amphetamine—not chemically, not in terms of its half-life, not in subjective experience, and not in any study that tracks behavioral or long-term effects. At best, it's a prodrug of an enantiomer of amphetamine. You are also mistaken about the study. Reading even the abstract would clear that up for you.
Let me clean up the unnecessary, convoluted language before I answer: Q: Does it stop being called "abuse" once a doctor prescribes it? A: No. The prescription stopped hospitalizations due to amphetamine overdose.
Q: Is it simply safer to use drugs with a doctor's help? A: That was not answerable based on the study's design. It is also not a useful question to ask in this context, since it's comparing apples and oranges. Some of the worst cases of drug abuse are created and maintained by doctors. However, taking drugs collaboratively with a doctor is probably safer on average than getting them from random webpages.
Q: Is this specific amphetamine safer than others? A: Yes, as is the case with any substance we ingest. You can quibble over the details, but beer is safer than hard liquor. Likewise, different medications in the same category or receptor affinity group have different LD_{50} doses (the ratio of the clinically effective threshold to the threshold where 50% of subjects would die).
No, I was merely inquiring after what appeared to be a misunderstanding but apparently wasn't.
> Lisdexamfetamine is not amphetamine
Just to clarify, this topic is always needlessly confusing because "amphetamine" is used to refer to both a distinct chemical as well as an entire class of chemicals. Lisdexamfetamine is _an_ amphetamine in exactly the same way that codeine is an opiate (ie a prodrug of).
I'm not sure why you think I'm mistaken about the study nor why you are so condescending about a misunderstanding rooted in terminology. You yourself state that it is about relative drug safety and the study is also quite clear about this so it would seem that we were in agreement all along.
If you look elsewhere in my comments, I have no problem calling myself an idiot when I make mistakes. But I hate the noise that is bad faith arguing concealed in fancy words.
Person you responded to suggested P( overeating | undereating ) as opposed to your P( overeating ). I expect the effects of those two conditions would tend to cancel each other out in observations.
> As seen in studies where people that start lisdexamfetamine (ADHD medication common in the EU) have a huge reduction in actual amphetamine abuse.
Perhaps I misunderstand you but lisdexamfetamine _is_ an amphetamine. That reads like saying that people prescribed an opiate exhibit reduced opiate abuse. It seems either tautological (not abuse because permitted) or obvious (cooperative supervised use reduces bad things happening) or perhaps related to drug safety (A simply being safer to use than B).