One self-boosting drug obtained, something really good (3-7)

I believe the answer is:

ego-tripper

'one self-boosting' is the definition.
(a self-boosting or egotistical person)

'drug obtained something really good' is the wordplay.
'drug' becomes 'e' (E is another name for ecstasy).
'obtained' becomes 'got' ('get' can be a synonym of 'obtain').
'something really good' becomes 'ripper' (ripper can mean something excellent).
'e'+'got'+'ripper'='EGO-TRIPPER'

I've seen this clue in The Guardian.

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