New Study: Meth Far More Dangerous to Adolescent Brains
But researchers said the brain scans of adolescents as young as 12 revealed more profound changes in the very part of the brain involved in resisting temptation and delaying gratification. And the youths’ meth use caused much stronger cravings, leading study authors to conclude, among other things, that the younger the user, the more devastating the addiction.
“When that brain region is influenced, it then creates a vicious cycle in adolescents with already less control over their impulses than adults,” said In Kyoon Lyoo, MD, PhD, of Ewha W. University in Seoul, in an interview. “As we mature into adulthood, we have more control over our impulses. But if meth damages that part of the brain before it’s fully developed, it becomes a difficult story for adolescents trying to control risky behavior or stop using meth,” Dr. Lyoo said.
Lyoo is the first author of the study, which was published in February 2015 in the journal Molecular Psychiatry. The study’s senior author is Perry F. Renshaw, MD, PhD, MBA, University of Utah psychiatry professor and investigator at Utah Science Technology and Research Initiative. The study is one of the largest of its type.
One More Piece of the Meth Puzzle
The researchers introduced their findings by noting that the adolescent years are a time of “heightened vulnerability both to addictive behaviors and drug-induced brain damage. Yet, only limited information exists on the brain mechanisms underlying these adolescent-specific characteristics.”
Lyoo, Dr. Renshaw and colleagues from two universities in South Korea performed brain scans on 225 South Koreans, of which 111 were adolescents and 114 were adults. Of the youths, 51 were meth users and 60 were not. Of the adults in the study, 54 were meth users and 60 were not.
What the researchers found was damage to gray matter, which involves executive function. But in the youths — age 12 up to 18 — the meth caused the most deterioration to the white matter, the brain’s communication network. Function can be impaired if these “highways” are disabled, Lyoo said.
“There is a critical period of brain development for specific functions, and it appears that adolescents who abuse methamphetamine are at great risk for derailing that process,” Renshaw said in a University of Utah news announcement. “I think the results show it is hugely important to keep kids off drugs.”
The researchers found that the damage in adolescents resulted despite a far smaller intake of meth than the amount adults ingested.
Known by numerous slang terms, including “crank,” meth is a powerfully addictive stimulant that quickly cripples the user with dependency. It causes a surge of pleasure thought to result from the release of high levels of the neurotransmitter dopamine. The high fades, but leaves meth users craving even more.
In September 2013, the National Institute on Drug Abuse (NIDA) reported that dopamine is involved in motivation, the experience of pleasure, and motor function. “The elevated release of dopamine produced by meth is also thought to contribute to the drug's deleterious effects on nerve terminals in the brain,” the NIDA report stated. In chronic use, meth alters the brain’s wiring by destroying the dopamine receptors. Even in low doses, meth can send users into days of sleeplessness and lack of appetite. In a meth overdose, convulsions that go untreated may be fatal.
Recovery from meth addiction can take years of medicine and behavioral therapy. The dopamine receptors destroyed by meth take up to a year to regrow. So until that happens, meth-dependent people feel almost no pleasure.
There are no FDA-approved drugs for treatment of meth cravings or withdrawal (unlike for alcohol), Lyoo said, so there’s a need to develop such medications. Many former meth users succumb to depression so severe that they frequently relapse.
Despite encouraging signs of a decline in meth use in the past decade, America's meth problem hasn’t gone away.
The Math of Meth
Some numbers and facts about meth and its use
- In the U.S. in 2013, meth ranked just behind heroin as the fourth-most-mentioned illicit drug in emergency room visits. (Cocaine was No. 1 and marijuana was No. 2.) And in many places, meth still has the dubious distinction of ranking higher than opiates in ER visits, especially in the West. In Hawaii and the City of San Diego, for example, meth ranked first among the most-mentioned illicit drugs in ER visits. It was second in San Francisco and third in Denver and Phoenix, according to the NIDA’s Community Epidemiology Work Group.
- The United Nations Office on Drugs and Crime reports that amphetamine-type stimulants including meth are the leading illicit drug used by adults and juveniles in many Asian countries.
- The NIDA estimated that about 1 out of every 20 people in the U.S. have tried meth at some point, and the 2012 National Survey on Drug Use and Health reported that 1.2 million U.S. residents — about 1 in every 250 — used meth at least once in the 12 months prior to the survey.
- The good news: That's a drop to 0.2 percent of the population as compared to 0.3 percent six years earlier.
The new meth study’s broader implications, Lyoo said, may help illuminate the abuse of other drugs, and the “severe” behavioral issues and relapses particularly challenging in adolescent drug addicts.
What’s next: Follow-up of the study subjects to examine the longer-term impacts of chronic meth use and whether the damage is reversible.
By Nancy Wride
Follow Nancy on Twitter at @NWride