Driving Under The Influence Of Alcohol Or Drugs And The Effects They Have On Your Brain


Everyone knows that when a person is under the influence of certain drugs, their driving may become impaired, but not everyone knows why.

Let’s start with the most common drug: alcohol. Alcohol is a depressant. Depressants cause the central nervous system to slow down, usually by enhancing a neurotransmitter called gamma-Aminobutyric acid (GABA). GABA reduces a person’s nerve cell excitability (the process that transmits information in our brains). Without GABA, we’d be a “bundle of nerves.”

Because many depressants, including alcohol, enhance GABA, nerve cell activity is further slowed down; that is why drinking alcohol (or taking depressants) is often used to “relax and unwind.” The effect of a drug-amplified GABA swimming around in our brains is to slow down those nerve cells to the point where our brain is functioning at a slower pace. No wonder people under the influence of alcohol or other depressants start slurring their words, stumbling, and often appear to act stupid—their neurotransmitters are firing on slow-motion. And it is also this effect that causes poor judgment and a slowdown of reaction times.

Even small amounts of alcohol or low doses of depressant drugs will initiate this effect—that’s the “buzz.” While many people believe they are in control and that they are okay to drive or complete other complex tasks, the depressant effect on the brain cannot be counteracted by a person’s resolve to control the effect because it is the brain itself that is in control and the depressant-influenced brain has been compromised by the drugs effect on the neurotransmitters.

In addition to alcohol, other common depressants include benzodiazepines, barbiturates, and opiates. These drugs are often prescribed (for example, Xanax, Clonopin, Valium, Ativan, Vicodin, and Percocet). As I discussed in a previous blog post, just because a drug is prescribed doesn’t mean it is safe or legal to drive after taking the drug. These drugs have the same depressive effect on the brain as alcohol does.

On the flip side are stimulant drugs. These drugs include prescription drugs such as Adderall and Ritalin and street drugs such as cocaine, methamphetamine and ecstasy. Stimulants also affect the central nervous system but unlike depressants, these drugs increase certain neurotransmitters in the brain, most notably, dopamine—the so-called “feel good” chemical. This is why the use of stimulants causes a feeling of euphoria. Unlike depressants, stimulants speed up the messages going between the brain and the body.

You might think that stimulants would improve one’s driving but this is not true. Stimulants can cause a person to misjudge reality and react accordingly. The effect of stimulants also often causes a person to be over-confident and believe his or her driving skills are better than they actually are. The increased firing of neurons caused by stimulant use may cause a person to drive aggressively or at high speeds. In short, stimulants have the effect of impairing a driver’s judgment making him or her feel highly competent and invincible, when in reality his or her driving is erratic and dangerous.Driving under the influence of any drug, even one prescribed by your doctor, that affects your ability to drive safely is unlawful in the State of California and can have devastating effects. Over 1/3 of all traffic fatalities in the U.S. involve a driver under the influence of alcohol or other drugs.

If you would like to know more about the laws regarding driving under the influence of alcohol or other drugs in California, contact Orange County Criminal Defense Attorney William M. Weinberg at his Irvine, California office at 949-474-8008.