High School seniors who use heroin most likely started their drug use with opioids, according to a study published in Drug and Alcohol Dependence.

The study states that 12.4 percent of students reported using nonmedical opioids and 1.2 percent reported heroin use. When the number of opioid users increased, so did the heroin users. Three-quarters of heroin users also reported using opioids. Additionally, those who used opioids within the last 30 days were also more likely to use heroin.

The study found that females and students with two parent households were least likely to report drug use, as well as black and Hispanics. Whites were more likely to report drug use.

This data was gathered from the Monitoring the Future study, which looks at the behaviors, attitudes and values of American students. The study is given to 15,000 students in over 130 public schools through the United States.

Researchers on the study emphasize that prevention, intervention and treatment are necessary for high school drug users.