What is “High”? A Look at the Legalization of “Marijuana” Part II

What is “High”? A Look at the Legalization of “Marijuana” Part II

A recent survey found that 6.8 percent of drivers, mostly under age 35, who were involved in accidents tested positive for THC; alcohol levels above the legal limit were found in 21 percent of such drivers.”-National Institute on Drug Abuse (NIDA)


In the first installment of “What is ‘High’? A Look at the Legalization of ‘Marijuana’”, we examined what impact the legalization of marijuana may have on states tax revenue as well as the incorrect perception that the word “legal” equates to “safe”. Per the National Highway Traffic Safety Administration, “Marijuana has been shown to impair performance on driving simulator tasks and on open and closed driving courses for up to approximately 3 hours.”1 Although legalization allows individuals to use marijuana, it does not allow for driving while impaired by the drug. In this installment we will briefly look at the value set by some states for the concentration of tetrahydrocannabinol (THC) in blood, which depending on the state and reason (recreationally vs. medical) for use ranges from 2 to 5 ng/mL.

Pharmacological effects of marijuana vary with dose, route of administration, experience of user, vulnerability to psychoactive effects, and setting of use.”- National Highway Traffic Safety Administration  

It is difficult to make a connection between an individuals THC blood or plasma concentration and level of impairment.1 Factors that influence the values include an individual’s pattern of use and dose. The concentration of the active components of marijuana can vary from one source of drug to another. Tolerance can develop to some of the effects of marijuana, giving the user the sense that they lack impairment. “In long term users, even after periods of abstinence, selective attention (ability to filter out irrelevant information) has been shown to be adversely affected with increasing duration of use, and speed of information processing has been shown to be impaired with increasing frequency of use.”1

More research on the use of marijuana is needed and hopefully will be a positive outcome of this challenging and multifaceted issue.3,4 To learn more about marijuana use and effects the National Institute on Drug Abuse and National Highway Traffic Safety Administration are both excellent sources of information.


1. Drugs and Human Performance Fact Sheets: Cannabis / Marijuana ( Δ 9 -Tetrahydrocannabinol, THC).  National Highway Transportation Safety Administration. Accessed March 24, 2014 http://www.nhtsa.gov/people/injury/research/job185drugs/cannabis.htm

2. Driving Under the Influence (RCW 46.61.502). State of Washington. Accessed March 27, 2014 http://apps.leg.wa.gov/RCW/default.aspx?cite=46.61.502

3. High Time for Advancing Marijuana Research. Nature Neuroscience 17, 481(2014). Accessed March 27, 2014. http://www.nature.com/neuro/journal/v17/n4/full/nn.3692.html

4. What Kinds of Marijuana Research Does NIDA Fund? National Institute on Drug Abuse (NIDA). Accessed March 27, 2014. http://www.drugabuse.gov/drugs-abuse/marijuana/marijuana-research-nida


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