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Drug Addiction Changes the Brain

10 December 2012
Published in Health
Written by  Kim Schuske
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Addiction to drugs or alcohol is a devastating disease that infiltrates every aspect of a substance abuser's life. Over time, it can alter a person's personality, destroy relationships, and cause serious, long-lasting, health problems.

"They always think 'I'm bigger and better than the drug,'" says Glen Hanson, Director of the Utah Addiction Center, referring to those who get caught up in abusing drugs. "And then as they continue to use it, it turns from abuse into dependence and addiction, and then the drug controls them."

The problem of addiction is pervasive. Almost everyone has a family member, friend, acquaintance, or is themselves affected by the disease. According to a 2010 study by the Substance Abuse and Mental Health Services Administration, 23 million Americans - 9.1% of the population - were in need of treatment that year for a substance abuse problem. Only 2.6 million received it.

Even if abusers receive treatment, relapse is common, occurring at a rate between 40-60%, according to the National Institutes of Drug Abuse. These statistics are similar to relapse rates for other chronic diseases, such as diabetes, hypertension, and asthma. "This is a disease that never goes away once it's happened," says Hanson. "They always have to be vigilant and pay attention to it because it can come back."

Researching New Treatments for Methamphetamine Addiction

The United States is committed to studying and treating drug addiction. The National Institute on Drug Abuse has an annual budget of about 1 billion dollars and funds approximately 85% of the substance abuse research in the world.

One recipient of this funding is Perry Renshaw, Professor of Psychiatry at the University of Utah, who uses Magnetic Resonance Imaging, or MRI, to investigate why methamphetamine dependence is so hard to overcome.

"What we see is that parts of the front of the brain, in the frontal lobe, seem smaller than they should be compared to individuals who don't use methamphetamine." The physical change correlates with alterations in behaviors that are controlled by that part of the brain, including memory loss and a shortened attention span.

He adds that perhaps most importantly, these patients find it increasingly difficult to derive pleasure from things they used to find rewarding. "That's one of the reasons why so many people who become methamphetamine-dependent find that their lives are falling apart."

Using an advanced form of MRI to zero in on brain chemistry, his team also sees decreased levels of two chemicals: adenosine triphosphate (ATP), which provides energy to nerve cells, and N-acetylaspartate (NAA), one of the brain's most abundant molecules.

These results may open a new window for treating methamphetamine dependence, for which there are currently no FDA approved medications. Since ATP and NAA are naturally occurring, Renshaw's group is testing whether taking dietary supplements could be a simple way to boost chemical levels.

Initial results from a small, pilot study in South Korea suggest the approach is working. "We've found that an over the counter natural supplement called CDP choline, or citicholine, seems to not only reduce drug use, but also to increase levels of NAA," says Renshaw. His group has just completed a larger study of Utah patients and expects to report the results early next year.

An Uncertain Future

While Renshaw says some aspects of brain functions appear to recover over time, it remains largely unknown what the long-term effects of methamphetamine use are. "We know that there is some, but probably not complete, recovery of many of these things that are seen when the individual was using drugs at their heaviest period of drug use."

Glen Hanson, Professor of Pharmacology and Toxicology at the University of Utah, points to studies suggesting that methamphetamine users may be predisposed to Parkinson's disease. With a disease onset of age 50 or older, typical symptoms include tremors, and difficulties with movement and coordination. Methamphetamine damages the dopamine reward pathway, the same biochemical pathway that normally allows people to feel pleasure, and is compromised in the brains of Parkinson's patients.

"We do see that in methamphetamine addicts, some of the early stages of Parkinson's disease," says Hanson. "For example, in Parkinson's disease, prior to when they have the tremors and all of the motor dysfunctions, they have cognitive dysfunctions...that looks like methamphetamine addiction so there seems to be this overlap."

In Utah, methamphetamine use peaked in 2006, but still remains a big problem. Overall the drug ranks third with 17.5% of people entering treatment saying it is their primary drug. For women it is the second most used drug behind alcohol.

Hanson says it is still a bit premature to truly evaluate the long-term effects of the drug, "The last epidemic with methamphetamine was the first time we've had thousands and thousands of people who have consumed huge amounts of methamphetamine for extended periods of time. And those folks haven't got to their fifties and sixties yet."

It may remain years before we fully understand the impact of methamphetamine abuse, and the abuse of other drugs on the brain. But Renshaw says the hope is one day the work by his and other labs will help them figure out how to treat this destructive disease.

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