Even Occasional Stimulant Abuse Alters Young Adults’ Brains
Illegal stimulant drugs of abuse available in the U.S. include cocaine and most forms of methamphetamine. Stimulant medications available in the U.S. include amphetamine and a related substance called dextroamphetamine (both found in the ADHD medication Adderall), methylphenidate (found in the ADHD medication Ritalin) and certain forms of methamphetamine. Each of these substances produces its own characteristic effect; however, all of them are capable of triggering diagnosable cases of stimulant abuse or stimulant addiction (known collectively as stimulant use disorder under guidelines established by the American Psychiatric Association). As a rule, addiction-related risks arise in people who repeatedly abuse a stimulant drug or medication and subsequently experience long-term changes in their brains’ normal chemical environment.
Frequency of Abuse
Public health officials in the U.S. regularly track the number of people who abuse stimulants. One of the ongoing projects designed for this purpose is the National Survey on Drug Use and Health, a nationwide endeavor sponsored by the Substance Abuse and Mental Health Services Administration. According this survey’s most recent findings (which cover parts of 2011 and 2012), about 0.5 percent of Americans over the age of 11 abuse a prescription stimulant in any given month. In addition, roughly 0.6 percent of Americans over the age of 11 use cocaine, one of the most commonly abused illegal stimulants. The results of the National Survey on Drug Use and Health also indicate that the highest rates for the use of all illegal/illicit substances (including stimulants) occur among young adults between the ages of 18 and 25. Approximately 24 percent of people between the ages of 18 and 20 abuse an illegal/illicit substance in the average month. People between the ages of 21 and 25 abuse such substances at a rate of roughly 20 percent in the average month.
The Impact of Occasional Use
In the study conducted by UC San Diego, a team of researchers used a real-time imaging technique called functional magnetic resonance imaging (fMRI) to examine the brains of a group of young adults between the ages of 18 and 24 who had occasionally abused a stimulant drug or medication. The researchers defined occasional abuse as misusing a stimulant substance anywhere from roughly 12 to 15 times. For comparison’s sake, the researchers also examined the brain function of a second group of young adults in the same age group who had no previous history of involvement in stimulant abuse. Participants in both groups were asked to perform a series of computer tasks that allowed the researchers to assess their brain responses and reaction times.
After comparing the two groups, the researchers concluded that the occasional stimulant abusers had a reduced ability to anticipate when they needed to quickly stop performing a given action. When they looked at the results of these individuals’ fMRI scans, the researchers also concluded that the observed reduction in the ability to anticipate was accompanied by a measurably slower rate of activity in the part of the brain responsible for controlling anticipatory reaction times. The ability of the occasional stimulant abusers to anticipate a required action grew worse as the complexity of the necessary action increased.
Significance and Considerations
The researchers believe that their work may help explain why people with stimulant addictions have such a hard time controlling their substance-using behavior. Essentially, these individuals may not be fully able to use internal and external cues as a means of anticipating when they need to modify or discontinue their actions. In the future, the researchers intend to investigate whether the changes in brain function they uncovered in occasional stimulant abusers are reversible or represent permanent alterations in affected individuals. They believe that certain types of brain exercises may have a beneficial effect.