Opposition to drug use is often couched in concern about children, but today's kids are using fewer drugs than in the past. And, according to a survey of risky behavior, San Francisco's young people are using fewer drugs than those nationally.

The San Francisco Unified School District, in conjunction with the U.S. Centers for Disease Control, surveys its high school students biannually to asses drug use, eating and exercise habits, and other possibly risky behavior.

Over the last 12 years, alcohol has been the most frequently abused substance among San Francisco high school students and usage rates have held fairly steady, dropping from 59.2 percent to 53.2 percent for one-time use, and from 27.5 percent to 22.3 percent for habitual use. The corresponding national rates have dropped from 79.1 percent to 75 percent and from 50.8 percent to 44.7.

Yet more people are seeking help for marijuana use than alcoholism. According to the Community Behavioral Health Services division of the city's Department of Public Health, 36 percent of young people receiving substance abuse treatment are marijuana users and only 21 percent are treated for alcohol abuse.

The higher rates of treatment could explain the large decline in marijuana use since 1997.

The number of students who have tried marijuana dropped from 33 percent to 22.8 percent, and habitual use has dropped from 17.1 percent to 11.4 percent. This mirrors the national trend in which rates dropped from 47.1 percent to 38.1 percent and from 26.2 to 19.7 percent for lifetime and habitual use, respectively.

The decline in marijuana use is only surpassed by that of cigarette abuse, which has dropped by almost half from 60 percent to 36.5 percent for lifetime use and from 19.1 percent to 8 percent for habitual use.

A current year study, which does not include trend data, shows that rates of cocaine, methamphetamines, and steroid use are below the national average, all hovering around 5 percent.

The surveys only collect data on illicit drug use and do not include the abuse of prescription drugs, which Jim Stillwell, manager of substance abuse service for the San Francisco Department of Health, said is on the rise.

They get pills from their parents, he said, and because they see adults take them, they don't seem as risky.