I think that here you are using "addicted" with accuracy/ a precise neurological meaning
I use them (*) but I've never been addicted/craved to an amphetamine-type stimulant .
Sex doesn't make me crave for amphes. Amphes do make me crave for sex... not it is untrue. If under the influence I start to jerk( that is, every time I use), than I can not stop because it is so pleasurable.
I think this is different from the learn/cue thing.
(*) not exactly, expecially mephedrone.
Meth is more straight on to sex and pleasure, with meph there is less push but an indirect effect.
The serotonin/empathogenic side enhance sexual fantasies and make sex ( jerking) better by this way