This is your brain on drugs

The auditorium at South Side High School was packed on March 2 for a special discussion of the effects of drugs on the brain.

More than 800 people crowded in to hear Dr. Steven Dewey, a neuroscientist from the Feinstein Institute for Medical Research in Manhasset, give a talk titled, “The effects of addictive drugs on the human brain.” The lecture was made possible by the Rockville Centre Coalition for Youth.

Dewey, who is also a professor of molecular medicine at the Hofstra Northwell School of Medicine, has been studying the effects of addictive drugs on the brain for decades. He uses advanced brain imaging to illustrate the ways in which drugs affect the brain’s chemical makeup, and the lasting damage they can do.

He has spoken at many schools on Long Island over the years, to parents and students alike. “I’m just here to show you what I see every day,” he said.

And what he sees every day is the change in brain activity in children that drug dependency causes. And he sees more of it now than ever before. “The number of substance abusers we’re seeing has increased more in the last five years than I’ve seen in the last 35 years,” Dewey said.

He explained that all addictive substances affect a chemical in the brain called dopamine, which makes people feel happy. The level of dopamine goes up and down naturally during the course of a day. Something good, like a win by a favorite sports team, increases dopamine by 5 or 6 percent. Likewise, something that makes someone sad decreases it about the same amount.

Drugs, however, increase dopamine much, much more. Alcohol, depending on the dose, can increase dopamine by 1,000 to 2,000 percent, and marijuana, by 2,000 to 5,000 percent. Methamphetamine, also know as crystal meth, can increase dopamine 900,000 percent. That makes it the most addictive drug, Dewey said.

He also explained what makes some people more likely to use drugs. Some people, he said, naturally have brain dopamine that’s 5 or 6 percent higher than average. Those people, according to Dewey, are more likely to try something different.

“We have really good, and really reproducible, evidence that the reason some kids go out and use a drug and some kids don’t is that they have brain dopamine that’s just a little bit higher,” he said. “And that little bit higher seems to underlie compulsive behavior. That is, the willingness to try something new.”

And the No. 1 reason people repeat the behavior, he said, is environment. Dewey said his studies have shown that when people take mood-altering drugs, everything about the situation is imprinted in their brains. When they’re re-exposed to a part of that situation — music, for example — the part of their brain that controls the motivation to get something they need turns on.

Dewey talked about different drugs’ effects on the brain, and what happens when narcotics are abused. Long-term alcohol abuse dulls the brain. The brain becomes less able to rebuff the effects of other drugs, so long-term drinkers become addicted to other drugs faster.

He also explained that addiction is something that starts in adolescence, while the brain is still developing. Marijuana, in particular, arrests the development of the frontal lobe of the brain. “The frontal lobe is what allows you to take data points and make a decision based on some projected future,” he said. “So when you start smoking pot in adolescence, you arrest the ability to make adult decisions.”

Marijuana today, he said, is also laced with other drugs. In Dewey’s own studies, he has found that almost three-quarters of the marijuana that people have shown him has been laced with methamphetamine, making it much more potent and addictive. “The majority of pot today has meth in it,” he said.

But the drug of choice these days is heroin, which is a growing problem on Long Island and across the country. The epidemic began a few years ago, when doctors over-prescribed painkillers, and children experimented with their parents’ medications. For the price of a single pill, an addict can buy multiple envelopes of heroin.

It’s also extremely pure — about 94 percent, Dewey said — meaning it no longer has to be injected, but can be snorted.

Prolonged heroin and opiate abuse, he explained, can damage the brain much like advanced multiple sclerosis, and is irreversible.

But Dewey stressed that while opiates are addictive, they’re not when they’re used correctly. “No one gets addicted to an opiate in the presence of pain,” he said.