Age itself is one of the most significant variables in understanding marijuana use. Past-year use of marijuana increasesd with age, to a peak prevalence of about 23 percent among 18- to 25-year-olds, before declining to about 44 percent among persons aged 35 and older.

Additionally:

From age 12 to age 13, the proportion of teens that who say they could buy marijuana if they wanted to more than triples, from 14 percent to 50 percent.

From age 12 to age 13, the percentage of teens who say they know a student at their school who sells illegal drugs almost triples, from 8 percent to 22 percent.

From age 12 to age 13, the percentage of teens who say they rely most on their parents’ opinions when making important decisions drops by almost one-third, from 58 percent to 42 percent.

By age 14 and 15, marijuana use in the past year increases to 16 percent.

Marijuana smoking among 8th graders increased from 12 percent in 1991 to 22 percent in 1997.

Gender

Marijuana use — whether lifetime, past year or current — is most common among males. Among adults, male smoking rates for marijuana are nearly twice those for females. In the total surveyed population, males were about 70 percent more likely than females to have used marijuana in the past year (11 percent versus 6.7, nearly 7 percent). The only exception to the data showing more male smokers of marijuana than females occurs among children and teens. Given that marijuana is by far the most commonly used illicit drug, it is not surprising that gender and age patterns for marijuana are similar to the corresponding patterns for any illicit drug.

Race and Ethnicity

In almost every racial and ethnic subgroup, males are more likely than females to have used marijuana in the past year, except among Native Americans and Hispanics, where there is no significant difference between males and females. Males are more than twice as likely as females to be past-year marijuana users, except among Native Americans (16 percent of females vs. 14 percent of males). For example:

Hispanics (9.2 percent and 8.9 percent)

non-Hispanic blacks (7.7, nearly 8 percent of females used marijuana in the past year vs. 14 percent of males who used in the past year)

non-Hispanic whites (6.7, nearly 7 percent vs. 11 percent).

Among Asian/Pacific Islanders (2.0, 2 percent vs. 7.7, nearly 8 percent)

South Americans (4.2, more than 4 percent vs. 13 percent)

In general, males are at least three times as likely as females to be past-year marijuana users. The exception is among Native Americans and Hispanics, where there is no significant difference between males and females (e.g., Native Americans, 16 percent of females vs. 14 percent of males; and Hispanics, 8.9 percent of females vs. 9.2 percent of males).

White males have higher marijuana use than black or Hispanic males. Similarly, white females have higher levels of use than black or Hispanic females.

In 1991, according to the Centers for Disease Control and Prevention (CDC), 14.7 percent of students said they had used marijuana in the past 30 days. By 1995, that rate had jumped to 25.3 percent. Use among white students jumped from 15.2 percent to 24.6 percent; among Hispanics, from 14.4 percent to 27.8 percent; and among blacks, from 13.5 percent to 28.8 percent.

In every age group, Puerto Ricans and non-Hispanic whites are relatively high in past-year marijuana use, while Asian or Pacific Islanders, Caribbean inhabitants, Central Americans and Cubans are relatively low. Native Americans are relatively high at ages 12 through 34, but data for Native Americans at age 35 and older are is too sparse to yield a reliable estimate at age 35 and older. Non-Hispanic blacks are relatively high at ages 26 and older (e.g., 5.8, nearly 6 percent among individuals age 35 and older) but about average at younger ages. Mexicans, South Americans and other Hispanics are about average in past-year marijuana use.

Geography

Major U.S. metropolitan areas have higher rates of marijuana smoking, but the differences are quite small. However, youth in large and small metropolitan areas are significantly more likely than youths in non-metropolitan areas to report current marijuana use. Furthermore, among adults ages 26 to 34, marijuana use was much more common among those living in large metropolitan areas. Use of marijuana appears to be greatest among residents living in the West and North Central United States.

Education and Employment

Marijuana use is generally equal across all educational levels, except for higher rates of use in the past year among those with the least formal education and lowest rates of use in the past month among college graduates ages 26 to 34. Overall, college graduates report less use than those with some or no college experience.

Mark S. Gold, M.D. contributed to this report.

Facts about Marijuana Use