No methamphetamine, but nigga we get higher
Big Boi, dopamine, I mean I’m dope

from Big Boi (Ft. Killer Mike & Little Dragon) – Thom Pettie Lyrics on Rap Genius

Buncha wordplay here. First, while he doesn’t use meth, they steady get high (off life maybe?). And, when you get high, your brain emits more dopamine which gives the feeling of euphoria. Of course, the word “dope” is part of “dopamine” as well

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