Intimate debilitating disease that's quite shocking (4,2)
I believe the answer is:
dear me
'that's quite shocking' is the definition.
(expression of shock)
'intimate debilitating disease' is the wordplay.
'intimate' becomes 'dear'.
'debilitating disease' becomes 'me' (short for myalgic encephalomyelitis).
'dear'+'me'='DEAR ME'
(Other definitions for dear me that I've seen before include "Mild expression of distress from expensive self" , "how distressing!" , "Expression of mild regret from precious self" , "Expression of dismay" , "how sad" .)