Identifying teens at risk for hashish use

A new study, published in the American Journal of Drug and Alcohol Abuse by researchers affiliated with New York University's Center for Drug Use and HIV Research (CDUHR), was among the first to examine prevalence and correlates of hashish use in a nationally representative sample of US high school students.

Analyses focused on data collected from high school seniors (weighted N=10,597) in years 2007-2011 (2011 was the last year recreational marijuana use was still illegal in all US states). The researchers determined how sociodemographic factors and reasons for marijuana use were related to recent (12-month) hashish use.

"Nearly one out of ten teens reported ever using hashish and it was used by a quarter of lifetime marijuana users," said Joseph J. Palamar, PhD, MPH, a CDUHR affiliated researcher and an assistant professor of Population Health at NYU Langone Medical Center (NYULMC). "Hashish and other marijuana use tended to share many of the same correlates; however, our results found that risk factors for regular marijuana use were often much stronger risk factors for hashish, a much more potent form of the drug."

The study, "Prevalence and Correlates of Hashish Use in a National Sample of High School Seniors in the United States," used data from Monitoring the Future (MTF), a nationwide ongoing annual study of the behaviors, attitudes, and values of American secondary school students. The MTF survey is administered in approximately 130 public and private schools throughout 48 states in the US. Roughly 15,000 high school seniors are assessed annually.

Both hashish and non-hashish marijuana can be smoked, vaporized, or cooked in food. Hashish can be used either in its natural state or converted into a more concentrated oil. However, compared to other marijuana, hashish usually contains a higher concentration of Δ9-tetrahydrocannabinol (THC), which is the most potent psychoactive cannabinoid. While a typical marijuana cigarette ("joint") contains only 0.5-5% THC, hashish tends to contain 2-20% with some estimates as high as 50%.

"Another key finding was that other drug use was a robust risk factor for hashish use," said Dr. Palamar. "Other illicit drug use, regular cigarette smoking, and frequent alcohol use each increased the risk for hashish use; however, a main finding was that as frequency of other marijuana use increased, so too did risk for recent hashish use."

Females were consistently at low risk for hashish use, but not general marijuana use. In some respects, these findings corroborate previous research that females tend to be at low risk for "harder" drugs than males. Hashish tends to be much more potent than other marijuana, and this study has determined that it is primarily the males that are at higher risk for use of this more potent form of the drug.

"Interestingly, our research found that students using marijuana because they identified as being "hooked" on it nearly doubled the odds for hashish use," said Dr. Palamar. "Since it is the more frequent marijuana users and those who feel they are hooked who are more likely to use hashish, in some instances hashish use can be used as an indicator of severity of marijuana use."

These findings can inform prevention and harm reduction in a time of increasing popularity of marijuana use and increasing rates of use of hashish products.