Yusuke Matsumoto, a 20-year-old college student, said he hardly ever wore a mask before the coronavirus, then discovered he felt more secure with one on, especially when he is in front of a large group. “My face turns red or becomes taut when I have tension, which I can conveniently hide,” he said.

Mr. Matsumoto said he now planned to wear a mask in situations such as giving a presentation.

Yuzo Kikumoto, a counselor who wrote a book a decade ago about what he termed mask dependency syndrome, said it shouldn’t be considered a major problem if someone uses a mask to facilitate social connections, as Mr. Matsumoto intends.

A sign of serious mask dependency, Mr. Kikumoto said, is when the wearer can’t leave home without one. For some people who lack self-confidence, a mask provides them with “physical and mental walls that protect them from others,” he said.