Answer:
In many of his works, Orwell describes the possibility of a future in which totalitarian states, independently of the ideology, exercise total control over the people, who instead of being citizens, become more like slaves.
A particularly scaring prospect is totalitarian control even over one's mind, because we as humans, assume that at least in inside our minds we will always be free.
This is actually one of the central premises of Orwell's most famous book: the dystopian classic 1984. In this work, the protagonist, Winston Smith, ends up becoming a slave to the totalitarian leader, Big Brother, not only because he is obliged to, but also because his mind has been so manipulated, that he willingly gives up his freedom of thought and becomes another drone of the system.
