Well, first off, I'd avoid using terms like "speed" because some people refer to meth
and speed as separate entities, and some people use them interchangeably. Chemically, the actions that meth and other amphetamines
have pharmacologically are pretty much the same, which is that they cause the release of massive amounts of dopamine
into the synaptic cleft. This is not to be confused with cocaine
or other psychostimulant drugs
which are dopamine reuptake inhibitors. That being said, there isn't a lot of difference between meth and other amphetamines except for minor differences in effects and potency. Methamphetamine
is incredibly powerful, and has a bigger effect than other prescription amphetamines but the core principles are the same. The differences come from what levels each of the neurotransmitters are balanced at that depend on what specific amphetamine
substance it is, the most notable of which are serotonin
, dopamine, and norepinephrine.
However, there are most certainly amphetamine substances that are not at all like most other amphetamines or meth, the most commonly known of these being MDMA
. While MDMA is a part of the amphetamine class, it's effects are considerably different, since they have much more to do with serotonin than with dopamine or norepinephrine. As a result the effects are different.