A point about the psychology
Let's forget the 'how many per cent of your brain'-thing for awhile, and think about the implications and psychological consequences of 'enhancing a primitive, limited mind to the level of Gods' (for the lack of better metaphor).
This would be akin to taking some ordinary bug, minding its own bug-business, walking around in the sand, being most fascinated about feces and whatnot - completely instinctual, from our perspective, 'sleeping mind' behaviour. No thinking involved, no awareness, no intelligence, no decisionmaking per se - - - then suddenly, elevating that bug's capabilities and mind to a regular human being's level.
It would basically be like if you were transformed into a bug physically, but otherwise, you remained the same, with same thoughts, aspirations, dreams, thoughts, feelings, etc.
Just how traumatic would that be? You're MINUSCULE, you're digging in sand, you have some weird bug instincts, your hands are some hairy tentacles and feelers, and your vision would be completely different.
My point here is, if the drug really worked as EXPLAINED (not as shown), it would have some -serious- implications, and the user would definitely feel as traumatic and as trapped as a 'God-mind inside a limited (how ironic) human body', as it would feel to be a 'human mind inside a limited bug body'.
Is there any difference between a bug expanding its mind to human level and starting to think and feel like human, but still remaining in the bug body, than there would be to change a human body into a bug?
So, would there be any difference between a 'God becoming trapped inside a human body' and a 'human mind expanding to a God-level while still trapped inside a body that's now too small for such a mind'?
The drug user should feel incredibly limited and trapped in a body, life, circumstances, world, life and city that's way too small for a mind that should be traveling the colorful dimensions of the Cosmos freely and (ironically) limitlessly!
The user should be as traumatic as a human being that suddenly has to live in a bug's body, or a bug, that's mind has suddenly been expanded to a human level.
But sure, 'doing well in a narrow path of selfish greed' is the next best thing, I guess.