A process of regression.

"And so, furtively, timidly, in solitude, at night, I indulged in filthy vice, with a feeling of shame which never deserted me, even at the most loathsome moments, and which at such moments nearly made me curse. Already even then I had my underground world in my soul. I was fearfully afraid of being seen, of being met, of being recognised. I visited various obscure haunts."

-Notes From the Underground