Thought a lot of especially shocking treatment described by communist (9)
I believe the answer is:
respected
'thought a lot' is the definition.
The definition and answer can be both related to thinking as well as being past participle verbs.
Perhaps you can see an association between them that I can't see?
'especially shocking treatment described by communist' is the wordplay.
'especially' becomes 'esp' (common abbreviation).
'shocking treatment' becomes 'ect' (electro-convulsive therapy).
'described by' is an insertion indicator (to describe can mean to form an outline).
'communist' becomes 'red' (red can informally mean communist).
'esp'+'ect'='espect'
'espect' inserted within 'red' is 'RESPECTED'.
'of' is the link.
Can you help me to learn more?
(Other definitions for respected that I've seen before include "Held in high regard" , "Looked up to" , "Held in esteem" , "'Esteemed, showed deference to (9)'" , "Had a high regard for someone" .)