A Northern Virginia high school student, who last month won a national award for a school newspaper article on student drug abuse, yesterday said that he had invented a psychiatrist quoted in his story.

Mike Gillette, 17, who graduated Monday from Gar-Field High School in Woodbridge, said the fictitious Dr. Kevin Olson was used to "summarize" information about teen-age drug abuse for the article, "Drugs--Statistics Are Shooting Up."

"I had about seven or eight sources for the story," Gillette said, "a policeman, a parent . . . , things like that. Olson was the medical authority. It was all information I had from other people. I just took the facts and put them in my own words."

Gillette's story, written for the November issue of the Gar-Field school newspaper "hyphen," won the 1983 Virginia Press Women's feature-writing award in April and went on to win the National Federation of Press Women's prize. A community fund-raising drive was reportedly under way to finance Gillette's trip to Vail, Colo., next month to receive a $75 award.

The hoax was discovered when rumors about the fictitious character reached school administrators last week. Assistant Principal Joyce Harte attempted to contact a Dr. Olson at Fort Belvoir in Fairfax County, where Gillette's story said he worked as a psychiatrist specializing in drug treatment.

Meanwhile, Gillette had confessed the deception to several friends.

"When I won the state contest, I was pretty happy . . . , then I got this letter saying I'd won first place in the nation, and I said, 'Oh, no.' " Gillette said he sought out his journalism teacher and then met with school officials Monday.

Although Harte said school administrators were "in a state of shock," Gillette said he was not "too upset" about the hoax. "I never thought it would go beyond the journalism classroom. My first mistake was doing it, and my second mistake was submitting it" for competition.

"Writing is just something I do as a hobby," said Gillette, who served as the school newspaper's business manager. "I wasn't planning to be a journalist. I'm going to college, I'm going to law school. I'm going to be a lawyer and then go into politics. I hope this doesn't ruin my career."

Gillette, who has been accepted to the University of Virginia, said he had already discussed the hoax with Jean L. Rayburn, the university's dean of admissions.

"I have to write her a letter all about it, and then she'll get back to me," Gillette said.

Rayburn said yesterday that the admissions committee will reconsider Gillette's application after his letter is received. "The fact that he has been so forthright about it will certainly stand him in good stead. . . . . I think everybody's entitled to make one mistake, don't you?" Rayburn said.

In addition to serving on the school newspaper staff, Gillette was president of the Gar-Field student government, the top ranked member of the tennis team and was voted Most Likely To Succeed by the senior class. He also worked as a freelance writer for The Potomac News.