According to a study published in Clinical Chemistry this past September, researchers from the National Institute on Drug Abuse (NIDA) conducted breath tests for the detection of recent marijuana use.
Exhaled breath was collected from chronic users (more than 4 times per week) and occasional smokers (less than twice per week) before and after smoking a 6.8% THC cigarette. Samples found that all of the breath tests from the chronic smokers were positive, with 90% positive results among the occaisional smokers. The tests were conducted between .5 and 2.5 hours after smoking.
These studies will undoubtedly be expanded and further testing will take place. It is significant because the incidence rate of marijuana-impaired drivers is likely to increase as the availability of the drug also increases through more legislative acts. Despite the argument that marijuana is less harmful than alcohol, the drug still impairs judgment and coordination and poses a threat to others on the road. Other applications may include workplace testing and other situations were drug use is prohibited.
Additionally, a long-term study conducted on marijuana use and cognitive ability showed that regular cannabis use that starts in adolescence lowers an individual’s IQ. Results from more than 1,000 individuals suggests that participants who started weekly cannabis use before the age of 18 dropped IQ points in proportion to how long they continued using the drug. In contrast, the IQ level of non-users increased.