A national permanent endowment to support youth drug abuse prevention has been established in First Lady Nancy Reagan's name by the 9-year-old Community Foundation of Greater Washington Inc., a spokeswoman for the group announced yesterday.

"We haven't put a dollar amount on it but we hope for enough of an endowment to make our first distributions in 1985," said Haida Sale, director of communications for the foundation that distributes an average of $2 million a year to groups working in social issues it considers high priority.

Working with national advisers to be chosen from among experts in the field of drug abuse prevention, the foundation will provide financial assistance to nonprofit or tax-exempt programs around the country that qualify, Sale said.

Calling the new endowment fund "in line with Mrs. Reagan's purposes and commitments to help the growing problem of drug abuse," White House spokeswoman Jennefer Hirshberg said the first lady was "very happy" to learn of its creation.

"It's going to be so important to the future lives of so many young people, especially those who could not otherwise afford treatment," Mrs. Reagan was quoted as saying.

Sale said the foundation administers about 45 family, corporate and other funds that are dispensed to a variety of causes that its officers consider to be among the community's most important current issues.

Sale said the Nancy Reagan Drug Abuse Fund is the first in the foundation's history to be of national scope.

Chairman of the foundation is Stephen Harlan, managing partner of Peat, Marwick, Mitchell & Co. President is Lawrence Stinchcomb, who worked closely with Mrs. Reagan's staff in setting up the endowment fund in her name.