A Roman Catholic bishop who once led the Diocese of Phoenix has been accused of repeatedly sexually abusing a boy decades ago, according to a lawsuit filed in Arizona Superior Court.

The lawsuit alleges that in the late 1970s and early ’80s, the bishop, Thomas J. O’Brien, placed his hands on the boy’s thighs, kissed him on the lips and performed oral sex on him. A hearing connected to the case was held this week, drawing additional attention to the lawsuit, which was filed last year.

In a telephone interview late Thursday, Tim Hale, the lawyer for the unidentified plaintiff, said the bishop’s acts caused his client to suffer from anxiety, panic attacks and emotional distress.

The abuse, a court document said, also caused the man to repress “all memory” of what had happened.

Mr. Hale said Arizona case law allows victims of childhood sexual abuse to file claims within two years of recovering those memories, regardless of when the crimes may have occurred.