Dotty Spencer on ecstasy shows charisma (8)
I believe the answer is:
presence
'charisma' is the definition.
(I've seen this in another clue)
'dotty spencer on ecstasy' is the wordplay.
'dotty' is an anagram indicator (a mad or 'dotty' version of the letters).
'on' is an insertion indicator (as in clothing 'on' a person).
'ecstasy' becomes 'E' (informal term for the drug).
'spencer' anagrammed gives 'presnce'.
'presnce' placed around 'e' is 'PRESENCE'.
'shows' acts as a link.
(Other definitions for presence that I've seen before include "Bearing, comportment" , "Impressive bearing" , "Immediate proximity" , "Imposing appearance" , "Being (significantly) there" .)