Teen Marijuana and Alcohol Abuse Can Lead to Brain Damage

By Hugh C. McBride

In a world in which adolescent drug abuse can appear to be approaching pandemic levels, some parents may be relieved to learn that their child is “only” drinking beer or smoking pot.

However, a number of studies indicate that any relief resulting from teen abuse of alcohol or marijuana may be misguided. Research teams have concluded that both alcohol and marijuana can be harmful to developing brains – and though alcohol appears to be the more dangerous of the two drugs, marijuana can also inflict significant damage.

Alcohol & the Adolescent Brain

A study that was published in the journal Clinical EEG and Neuroscience found that alcohol abuse appears to inflict more damage on the development of teen brains than does heavy marijuana use.

In a March 26, 2009 article on the Physorg website, writer Miranda Marquit reported that researchers from San Diego State University and the University of California San Diego attributed several types of damage to teen alcohol abuse:

When the brain abnormalities were measured — seen in terms of brain functioning and structure, cognitive tasks and quality of white matter — it appeared as though alcohol had a great effect than marijuana. Heavy drinking was defined as 20 drinks per month, and the abnormalities were detectable. In heavy marijuana users, abnormalities existed, but not to the same degree as those seen in alcohol abusers.

According to information provided on the website of the American Medical Association, researchers have noted the following relationships between adolescent and teen alcohol abuse and cognitive impairment (or brain damage):

Adolescents who regularly drink alcohol performed worse than non-drinkers did on tests that evaluated vocabulary, general information, memory, memory retrieval, and other areas.  The most significant gap between drinkers and non-drinkers was in verbal and nonverbal information recall, where adolescents who abused alcohol performed 10 percent worse than did subjects who didn’t drink.  Adolescents ages 15 and 16 who have histories of extensive alcohol use have been found to suffer from “significant neuropsychological deficits.”  Adolescents who regularly engage in alcohol abuse do worse in school, are more prone to violence, and are more likely to experience depression and suicidal thoughts.  Alcohol abuse can disrupt the sleep cycle, which can result in learning and memory impairments, as well as disruptions to the natural release of hormones that are related to growth and maturation.

Marijuana’s Effect on Developing Brains

A study that was conducted at The Children’s Hospital of Philadelphia concluded that young people (adolescents, teenagers, and young adults) who have histories of heavy marijuana abuse are more likely to experience disrupted brain development than are individuals of the same age who don’t use marijuana.

A Feb. 3, 2009 article about the Philadelphia study that appeared on the ScienceDaily medical news website reported that heavy marijuana abuse is associated with damage to areas of the brain that control attention, decision-making, language, memory, and executive functioning skills. The ScienceDaily article provided the following highlights from the research, which was led by Manzar Ashtari, Ph.D.:

The researchers performed brain imaging studies on 28 young men with an average age of 19. Fourteen of the subjects were heavy marijuana users (averaging five years of use, and six joints per day in the previous year), and the other 14 had no history of marijuana abuse.  Dr. Ashtari and his colleagues performed diffusion tensor imaging (DTI), a type of magnetic resonance imaging scan that measures the movement of water through brain tissues.
The brains of the subjects who had a history of heavy marijuana abuse showed abnormal patterns of water diffusion, which indicated slowed brain functioning.

“Our results suggest that early-onset substance use may alter the development of white matter circuits … [which] could slow information transfer in the brain and affect cognitive functions,” Dr. Ashtari said in the ScienceDaily article. However, he noted that his team could not establish a clear cause-effect relationship between the brain damage and the marijuana abuse, which means that the brain abnormalities could predate the marijuana abuse.

The Prevalence of the Problem

Alcohol and marijuana remain the most widely abused substances among American adolescents. The following statistics from the Teen Drug Abuse website offer a glimpse into the prevalence and effects of teen abuse of alcohol and marijuana:

Forty percent of those who started drinking at age 13 or younger developed alcohol dependence later in life.
Alcohol kills 6.5 times more teenagers than all other illicit drugs combined.
One in five 8th graders report having tried marijuana.  The National Institute of Justices Arrestee and Drug Monitoring System (ADAM) drug testing program found that 66 percent of underage male arrestees tested positive for marijuana.

A March 2007 Call to Action from the Surgeon General of the United States indicates that the problem of teen alcohol abuse remains a pressing issue:

The number of young people who drink and the way they drink results in a wide range of negative consequences affecting large numbers of underage drinkers and those around them. These consequences include risky sexual behavior; physical and sexual assaults; potential effects on the developing brain; problems in school, at work, and with the legal system; various types of injury; car crashes; homicide and suicide; and death from alcohol poisoning.

In addition, early initiation of drinking is associated with alcohol dependence both during adolescence and later in life.

Getting Help

Young people abuse alcohol and marijuana for a variety of reasons, including recreational experimentation, peer pressure, and an attempt to self-medicate depression or other types of emotional pain. Many cases of teen alcohol and marijuana abuse are symptomatic of underlying conditions (such as depression or anxiety), while other instances can be the cause of future damage (such as the brain damage described earlier in this article and a host of other medical complications).

If you suspect that your child is abusing alcohol, marijuana, or any other substance, don’t assume that this is merely a harmless “rite of passage.” While some young people can abuse alcohol and marijuana with little lasting damage, others will develop dependency or other conditions that can result in lifelong (and, in some cases, life-shortening) damage.

Depending upon the nature and severity of a young person’s abuse of alcohol or marijuana, remedying the problem can range from increased parental involvement to enrollment in a residential rehabilitation facility. Some young people respond well to limited intervention, while others require the more intensive experience that is offered at a wilderness program for troubled teens or a private therapeutic boarding school, where both the substance abuse and any underlying conditions can be identified and addressed.