Stout and drugs - leads to one's downfall perhaps (4)
I believe the answer is:
fate
'one's downfall perhaps' is the definition.
I can't judge whether this defines the answer.
'stout and drugs' is the wordplay.
'stout' becomes 'fat' ('fat' can be similar in meaning to 'stout').
'and' says to put letters next to each other.
'drugs' becomes 'e' (somebody 'on E' could also be 'on drugs').
'fat'+'e'='FATE'
'leads to' is the link.
Can you help me to learn more?
(Other definitions for fate that I've seen before include "Final issue" , "E.g. Clotho, Atropos" , "Predestination" , "One's lot" , "Inevitable destiny" .)