Professor: Genetic mutations can amplify drug addictions


Published: Thursday, March 14, 2013 at 5:13 p.m.
Last Modified: Thursday, March 14, 2013 at 5:13 p.m.

That some people are genetically prone to addictions is nothing new, but some scientists have expressed surprise at the degree of addictive tendencies.

For example, if you have a high-risk genotype for marijuana addiction and also suffer from neuroticism or anxiety, you have an eight- to nine-fold risk of becoming addicted to marijuana.

What's more, in-utero exposure to the drug might induce long-term addictive tendencies — at least in rats.

Professor Yasmin Hurd, a neuroscientist and professor of psychiatry at the Ichan School of Medicine in Mount Sinai, N.Y., cited these examples Thursday in a talk titled "The Vulnerable Brain: Understanding the Neurobiology of Addiction Risk." Her talk was one of two expert lectures delivered Thursday at the McKnight Brain Institute as part of brain awareness week, a global campaign to raise awareness of the brain.

Early addiction research in neuroscience focused on dopamine dependence — the "feel-good" chemical released abundantly in the brain when people use drugs. The flip side of this immediate surge is a long-term lessening of dopamine actually produced by the brain, which over time, decreases a person's ability to experience pleasure.

But scientists realized addiction in the brain was "much more complicated" than decoding dopamine circuitry, so they began looking at genetic mutations that might play a role.

"Clearly there is not one gene that makes someone a heroin abuser," Hurd said, adding, "Genetics has an important for understanding the vulnerability of heroin abusers."

Hurd noted that marijuana is the most widely abused drug in the U.S., while heroin and cocaine are the most addictive. Heroin overdose has the highest mortality rates of any drug.

One issue that interests Hurd is the effect of marijuana use by pregnant women on their babies. The scientists found that men were more vulnerable to addictions than women. Other studies have shown that people — especially men — with certain behavioral traits such as anxiety, when combined with a genetic vulnerability to addiction, or a mother who smoked while pregnant, were especially at risk.

"It's really showing how you could pass on (risks of addiction) to the next generation," Hurd said. "We really need to decrease the use of drugs in kids who show neuroticism and anxiety."

For that reason, Hurd said she doesn't support the legalization of marijuana that 18 states and the District of Columbia endorse.

She explained that adolescent brains still are developing and are more susceptible to addictions.

"It's too early to legalize a drug that we haven't studied significantly," she said, adding that she supports the medicinal use of the drug in pill, not smoked, form — unless people are terminal, in which case they should not have any restrictions.

Hurd's lecture was followed by one on memory later in the day by professor Paul Gold, a biology professor at Syracuse University in New York. Gold's lecture was designated the Inaugural William G. Luttge Lectureship. Luttge was the chairman of the neuroscience department at UF for 20 years before his retirement in 2004. He also was the founding director of the McKnight Brain Institute, which after Luttge's death last year established a permanent annual lectureship in his memory.

Luttge's wife, Michaelyn, and one of his sons, Ben, attended the lectures on Thursday.

"It's very special that this lectureship falls in this (brain awareness) week," Michaelyn Luttge said. "He was here all the time. He had a life well-spent. He was a proud father (of the Institute) and good manager, and left it up to them to follow through with what they started."

Contact Kristine Crane at 338-3119 or kristine.crane@gvillesun.com.

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