Yes.
Loneliness and isolation are the worst killers ... they erode from inside until one is reduced to a walking, breading corpse. Slightly feral.
No wonder ostracism from the tribe and solitary confinement are the oldest forms of torcher.
In our time technology gives an illusion of connection, which, while serves to, at least temporarily, reduce feeling of loneliness, in the same time isolates one further. For instance, typing this message and others on this forum gives an impression of interaction, and while, to the certain extent this is true, the fact remains that I have not spoken with another human being in real life for days. About anything, not to mention any meaningful type of exchange.
Different people need different amount of interaction with others. Some more and some less. But everyone needs some. Not being able to interact, communicate, belong leads to alienation, then annihilation.