You live like this, sheltered, in a delicate world, and you believe you are living. Then you read a book... or you take a trip... and you discover that you are not living, that you are hibernating. The symptoms of hibernating are easily detectable: first, restlessness. The second symptom (when hibernating becomes dangerous and might degenerate into death): absence of pleasure.
That is all. It appears like an innocuous illness. Monotony, boredom, death. Millions live like this (or die like this) without knowing it. They work in offices. They drive a car. They picnic with their families. They raise children. And then some shock treatment takes place, a person, a book, a song and it awakens them and saves them from death.
Some never awaken.