Popular mason disturbed about current sleep disorder (8)
I believe the answer is:
insomnia
'sleep disorder' is the definition.
(I've seen this before)
'popular mason disturbed about current' is the wordplay.
'popular' becomes 'in'.
'disturbed' indicates anagramming the letters.
'about' means one lot of letters goes inside another.
'current' becomes 'i' (symbol for electric current).
'mason' with letters rearranged gives 'somna'.
'somna' placed around 'i' is 'somnia'.
'in'+'somnia'='INSOMNIA'
(Other definitions for insomnia that I've seen before include "State of chronic sleeplessness" , "problem at night" , "Sleep disorder" , "In restless state" , "Condition affecting sleep" .)