^ the modes of action are very different, indole psychedelics mainly work through having high binding affinity with the 5HT receptor family because of their structural similarity to serotonin (5HT are among other things serotonin receptors) .. stimulants are different in that they're dopamine agonists, cause excitation of the CNS and sympathetic nervous system, they deplete dopamine levels from axon terminals and block its re-uptake by inhibiting enzymes which break it down. The reason stimulants are a bonanza for developing addictions is that cascades of dopamine into the nucleus accumbens is a central process for 'reward' sensations and generating repeated behaviour.

also most amphetamines are also at least mildly corrosive to brain tissue. but i don't know many people who do drugs like that because they're happy and well adjusted, i don't think it's an easy question to answer..