Prince mostly rational, taking no dope or weed? (12)

I believe the answer is:

hallucinogen

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'weed?' is the definition.
(thesaurus)

'prince mostly rational taking no dope' is the wordplay.
'prince' becomes 'hal' (I've seen this before).
'mostly' means to remove the last letter.
'rational' becomes 'lucid' ('lucid' can be similar in meaning to 'rational').
'taking no dope' becomes 'nogen' (I can't justify this - if you can you should believe this answer much more).
'lucid' with its final letter taken off is 'luci'.
'hal'+'luci'+'nogen'='HALLUCINOGEN'

'or' acts as a link.

Can you help me to learn more?

(Other definitions for hallucinogen that I've seen before include "mind-blowing" , "Psychoactive drug" , "Mind-bending drug" , "Mind-altering drug" , "Mind-affecting drug" .)

I've seen this clue in The Times.

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