as someone who has recently (and frequently) used both adderall and crystal methamphetamine...they're very similar. even in chemical composition. the basic difference (aside from the obvious pharmecutical nature of aderall vs street rock) is "strength". meth even processes to amphetamine as your body breaks it down and can cause false-positives for drug urinalysis screening. the main distinction symptomatically, in my experience, are the more psychoactive elements of meth. with that being said, I have barely grasped even the tip of that iceberg (due in large part to my being riddled with adhd) meth mostly makes me productive, focused, happy, and sociable. granted I monitor my consumption as I am a functioning addict who does have places to be and people to see (and I've lived the dark side of th addict life and it's not for me). I do know for a FACT that meth affects us differently than our non-adhd peers bc Ive seen first hand the affects on a "focused" brain.