A new report presented at the American Psychiatric Association's annual meeting suggests that drug testing may not be as accurate as doctors once thought.
According to researcher Dwight Smith, of the VA Medical Center in Black Hills, South Dakota, 5 to 10 percent of all drug tests reveal false positives and 10 to 15 percent yield false negatives.
Many common over the counter and prescription drugs can produce false positives for such illegal substances as marijuana, opioids and amphetamines. Some drugs that have been known to cause false positive results include cold medicines, which can show up as amphetamines, and the HIV drug Sustiva, which can cause positive tests for marijuana.
Smith added, however, that simply breathing in a room where people are smoking marijuana will never cause a false positive.
"Unless [they] were in the van with Cheech and Chong, that's not what happened," he told Web MD.
Fellow researcher Petros Levounis of the Addictition Institute of New York also added, "cocaine is cocaine -- you don't get many false positives or false negatives."
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May 15, 2026 15:25 ET Apart from the confirmation of Kevin Warsh as the next Fed chair, the main news on the economics front this week included key price data from the U.S. and the first quarter economic growth figures from major economies. Both consumer prices and producer costs have started to reflect the effect of supply shocks due to the Middle East conflict. In Europe, GDP data was in focus, while inflation data from China dominated the news flow in Asia.