[graeme]

Solitary confinement is widely considered to be torture, and what studied of Hikkomori exist suggest they have more suicidal thoughts and psychiatric disorders than the average.

The former suggests need for social contact is in our genes. There is a reason monks had monasteries for their life of withdrawal: they still had others around.

There are rare exceptions, the eremetic monks, but overall Hikkomori do not seem content. They are perhaps more comfortable than they felt out in the world, but I strongly suspect they are in a local maximum and could live much more satisfying lives.