At a small school in a remote section of Rockville three high school seniors slipped into caps and gowns, quickly looked around at the halls they would never quite forget and then nervously walked out to reenter the world they left when drug abuse led them to the brink of self-destruction.

Graduation day to these three students and three others who earned Graduate Equivalency Diplomas Monday at Second Genesis rehabilitation home meant more than the usual pomp and circumstance. It meant a return to the mainstream of life. And it meant leaving behind 58 other teen-agers who are still trying to overcome their own nightmares.

Once the students walked outside the walls of the rehabilitation home, they knew they would again run headlong into the same pressures that pushed them toward drugs. And of course the same crowd of friends--the ones who had provided both the peer pressure and the drugs--would still be hanging around, first asking how they had been and then asking them if they wanted to take a hit off a joint.

Temptation lying just around the corner is something they said was going to bother them, but it was a challenge they now knew they could handle.

"Things are going to be tough because I'll be alone a lot and I'll have to be careful of who I pick as friends now and because there won't be 50 other people around who can help me pick myself up if things start going wrong," said Donna S., 18, of Largo, before the graduation. (The teen-agers' last names are being withheld at their request.)

"But I know now that I can handle all of that; I know if I start dealing with those old friends again, they're going to want me to get back on drugs with them and if I do, all this hard work I've done, it's all gone with the first hit off a joint," continued Donna, who said she had used marijuana, speed, cocaine and LSD.

"But I know now how to be aware of all that and, in a way, I feel that I'm better than some of those people who are still doing the drugs. Those people just don't know what I've been through."

Graduation day for Donald W., a cheerful 18-year-old from Salisbury, was something special because he has overcome a serious drug and alcohol problem, and because he earned a Maryland senatorial scholarship of $800 a year for four years to attend Salisbury State College.

A year and a half ago, though, going to college did not seem even a remote possibility--just staying in school was hard enough, he said. It was then he took barbiturates and mixed them with whiskey. He ended up in a straitjacket in a hospital, charged with assault and battery of a police officer.

"I guess I started getting high when my parents started getting a divorce when I was 11," Donald said. "I guess I was just trying to get attention, but I just continued doing bad things and soon started stealing cars, breaking into houses, stealing from my parents, stealing from my grandparents--the whole time I was getting high, coming home drunk and stoned and just cussing out my parents awfully.

"I just treated my parents like they owed me everything and I didn't have to do anything to deserve what they gave me," Donald said. "And they tried to do all they could to help me, they even put me in a military school. Classwork was never a problem for me, school seemed pretty easy, but I wouldn't last long in a school. At the military school I was kicked out with three weeks left in school for coming back one night totally drunk.

"But now . . . I feel so good about myself. Like Donna said, I feel so much above people I know who still get high. I'm not about to let them pull me down to their level. Some of them use dope to handle problems in their life, but I've found out it really doesn't help anything."

Graduation day for Sondi D. was busy. After getting her diploma she rushed back to change from her cap and gown and get ready to play her part in the ceremony's drama presentation.

Before graduation, she reflected that Second Genesis is a setting far from her world in Baltimore that revolved around heroin and a 26-year-old supplier, parents who used drugs and a father who was in jail.

"I used to be really influenced by the guys I went out with," Sondi said. "We started doing marijuana, but soon went into harder stuff . . . and started staying out later and later. When my mother started noticing that I wasn't doing the things I should have been, we got in fights. One day she and I got in a really bad fight and she pressed charges against me and I was put in a girls' detention center and then a foster home. My mother said she didn't ever want to see me again.

"I couldn't deal with that, so I kept using drugs and my grades in school just kept dropping and dropping. Then when I was 16 I met this guy who was 26, when I was working at Gino's. We started to see more of each other and the whole time we were doing heroin together. At school things were really shaky because my grades were so bad and because I kept missing days. I eventually ran away from it all."

Donna Pyrdol, the teen-agers' teacher, said seeing her students on graduation day and seeing how far they had come to graduate was ample reward. The curriculum at Second Genesis is tailored to each student's level of progress before drug abuse halted their education. As a result Pyrdol taught everything from remedial math to reading. Montgomery County Public Schools, which employs Pyrdol, loans her to the nonprofit, private treatment agency.

One of the foundations of Second Genesis is that the students are not required to go to school. They have the choice of doing manual labor around the home, and if they choose to do neither they are required to wear a sign that describes their uncooperative attitude while they do even harder work such as dishpan duty. Prydol said she wishes all students could face such a choice.

"It seems to be really good for the kids to realize if they don't want to be in school that's fine, but they'll have to see the alternative is they'll have to work like a son-of-a-gun for the rest of their lives," Pyrdol said. "But these kids I teach just eat up the school work. On days that we have a holiday they'll moan and groan and complain that they want the day to learn more. They're so eager to catch up with what they've left behind."

The Friday before graduation, educational coordinator Eva Mahoney had a bit of bad news: the diplomas would not be ready for graduation and only blank rolls of paper would be presented. Sondi, Donald and Donna said they were disappointed, but it really didn't matter. Diploma or not, they were ready for the outside world.