San Francisco — Parents who over the last six years have built a national network to combat drug abuse have found some new, influential allies - teen-agers. At a recent conference here sponsored by the Atlanta-based PRIDE (Parent Resource Institute for Drug Education), high school students from San Francisco Bay Area communities shared top billing with drug-abuse experts and leaders of the now well-established national parent movement.
These Teens Who Care (TWC) - some former users of alcohol, marijuana, and other substances and other youths who simply persisted in their determination to stay ''straight'' - are affiliated with Parents Who Care Inc. (PWC), a parent organization that started in Palo Alto, Calif., in 1979. Marjery Ranch, executive director of PWC, explains how TWC came about:
''Parents Who Care members worked for about a year going around to different communities and presenting information about alcohol and drug use by children. They took some of their kids with them to some meetings, almost incidentally, and when the teen-agers described what was going on in the local social scene, they had a great impact on the listeners. The kids' credibility was very high.
''Realizing that if the teens were part of the problem, then they had to be part of the solution, PWC made the teen-agers part of the effort, including them in presentations whenever possible,'' Mrs. Ranch recalled. ''This had not happened before - I don't know why.''
TWC became a formal part of the PWC movement in the summer of 1980. By this time, the parent organization had spread to many other communities in the Bay Area and beyond. With the help of college students who had attended local schools and managed to resist peer pressure to join in ''partying'' - the universal term for getting together to drink and use drugs - meetings were held at which local teen-agers were shown how to organize parties without alcohol and drugs.
Follow-up group meetings between local high-school students and their parents resulted in frank discussions of the frustrations on both sides and the realization that both students and parents wanted the same thing: enjoyable social activities for the youngsters without drugs. Mrs. Ranch says one youth admitted: ''Parties (with drugs) are boring. You never really get to know anybody.'' Another said participants often ''couldn't remember anything about the party afterward.''
With the support of their parents, teen-agers began staging alternative parties, where it was made clear no alcohol, marijuana, cocaine, or other drugs would be permitted. A few teens who might otherwise have been ''partying'' in the usual fashion attended. Some said they had enjoyed themselves and would like to attend the next party.
This process is being repeated in many California communities and elsewhere in the United States. Progress is difficult to measure, Mrs. Ranch and other activists admit. It is most obvious to the families whose teen and even preteen members no longer feel left out or pressured to participate in drug use.
One of the most obvious results is the enthusiasm of youths in Teens Who Care and the expansion of their antidrug activities.
In 1981, Mrs. Ranch recalls, a group of students from Gunn High School in Palo Alto, where PWC originated, attended a PRIDE conference in Atlanta and ''made such an impression that groups were spawned all over the country.''
On that same trip, the youths testified before a Senate committee in Washington. Walter Hays, then 17 years old, told the senators: ''Because of my decision not to take drugs . . . I was always on the outskirts of the social scene. My involvement with Parents Who Care has changed things for me. It has let me know I am not alone. By helping me find and meet people who don't use (drugs), Parents Who Care has helped make me more sure of myself at school. I feel that I have a much stronger base than I did last year.''
Besides providing alternatives to ''partying,'' the teen-agers provide role models, says Mrs. Ranch, by abstaining even when attending social events at which others are drinking and using drugs. ''You don't preach,'' said one participant in a youth panel at the San Francisco conference, ''and you don't criticize. You just show you can have a good time without getting drunk or stoned.''
Said another: ''I don't abandon friends who do drugs. But they know I don't, and we still do things together. They're getting the message.''
Also getting the message are younger children. TWC members go to junior-high and even elementary schools to talk to groups of children. ''They have a big impact when they tell them, 'You don't have to get involved with drugs. Don't be stupid,' '' says Mrs. Ranch. ''The high-school youths know that peer pressure is especially great on junior-high students to experiment with drugs and alcohol.''
She adds that the teens ''are motivated to educate parents. They realize most parents have no idea the extent to which drugs and alcohol are being used by youngsters. You should see the parents' jaws drop when they hear what's going on from the kids themselves.''
The effort to influence other teen-agers and bring about a change in attitudes about drugs - especially with alcohol and drug use being portrayed both blatantly and subtly in the media - is challenging for the youngsters. So parents bring them together periodically for ''potluck'' dinners to reinforce each other, Mrs. Ranch explains.
There has been no formal evaluation of either PWC or TWC impact, she admits. ''Parents just look to see whether or not they see a change. We notice that statistics in terms of marijuana use are dropping.
''And the kids we're working with see that they do have an impact.''