Many deaths associated with drug use are not being counted as drug-related, according to a new study. The reported number of drug-related deaths among 15- to 64-year-olds in 2016 was 63,000. The new study concludes the actual number could have been as high as 142,000, HealthDay reports.

Estimates of drug-related deaths do not count other ways that drugs can lead to death, such as infectious diseases like HIV/AIDS and hepatitis, impaired judgment, suicide and circulatory disease, the researchers found.

“The drug epidemic is probably killing a lot more Americans than we think. That’s the main point we’re trying to make,” study co-author Dana Glei of Georgetown University said in a news release. Study co-author Samuel Preston added, “It’s obvious that the drug epidemic is a major American disaster. The basic records being kept are annual reports on the number of deaths from drug overdose. But that’s only part of the picture.”

The study was published the journal PLOS One.