Expert Compares Marijuana Impairment to Alzheimer’s Disease

by Terry Bryant

As more states allow sales of medical and even recreational marijuana, more impaired drivers may be on our nation’s roadways. While some believe that marijuana impairment may not be as severe as alcohol impairment, the effects of THC on drivers should not be ignored. THC, or tetrahydrocannabinol, is the active chemical in marijuana that accounts for the mind-altering “high” people get from the drug.

In an article for Heavy Duty Trucking magazine, Dr. Denise A. Valenti, an optometrist who is currently active in research related to vision, marijuana, cognitive function, and driving, compares the effects of THC on driver performance to the dysfunctions caused by Alzheimer’s disease. Marijuana users often report “tunneling” of vision or effects on peripheral vision, Valenti says.

Diminished peripheral vision is also seen in some dementia and Alzheimer’s sufferers and can influence thinking and behavior, according to experts on these diseases.

Valenti goes on to say that marijuana affects self-awareness, so drivers cannot accurately self-assess and judge how impaired they are. Valenti is president of Impairment Measurement: Marijuana and Driving, or IMMAD, a company working on developing a roadside eye goggle device that would help police measure marijuana impairment in drivers.

Measuring Marijuana Impairment

Currently, there are no good roadside tests for measuring marijuana impairment. Blood tests are needed to discover whether a driver is under the influence of marijuana and to what extent, but by the time these tests are taken, the amount of THC in the blood may have dissipated.

It is also difficult to accurately assess how many accidents are caused by marijuana use alone. After alcohol, marijuana is the drug most often found in blood tests of drivers involved in vehicle crashes, according to the National Institute on Drug Abuse, part of the National Institutes of Health. The agency reports that research studies of drivers under the influence of marijuana show an increase in lane weaving, poor reaction times, and altered attention on the road. But the actual role that marijuana plays in vehicle crashes is unclear because the drug is often combined with alcohol. Police may not test for marijuana impairment if the driver has already reached an illegal blood alcohol level or, as mentioned before, the amount of marijuana in the blood may have been reduced by the time the test is taken.

Stats on Drugged & Drunk Drivers

In any case, whether a person is driving under the influence of alcohol, marijuana or another drug, that driver is impaired and can be a danger to others on the road. The statistics about how many people drive under the influence of drugs and alcohol are frightening. A 2016 study by the National Survey on Drug Use and Health (NSDUH) showed that, in 2016, 11.8 million people aged 16 or older drove under the influence of drugs and 20.7 million were under the influence of alcohol when they got behind the wheel.

If you have had the unfortunate experience of being in an accident involving an impaired driver, you may be entitled to compensation for your injuries. The experienced attorneys at Terry Bryant Accident & Injury Law are here to help. Call us today at 1 (800) 444-5000 or contact us through our site’s online form.