the-chemistry-between-us

New love or drug use? It's all the same to your brain

Sep. 17, 2012 at 10:44 AM ET

Editor's note: Frequent TODAY.com and NBCNews.com contributor Brian Alexander's new book, "The Chemistry Between Us: Love, Sex, and the Science of Attraction," was recently released. "In a piece adapted from the book, Alexander and co-author Larry Young talk to a former user and argue that love is an addiction."

By Brian Alexander and Larry Young, PhD.

When Brian asks Fred Murray “Were you in love with drugs?” he smiles broadly and rolls his eyes at such a silly question.

Then the 59-year-old San Diego man laughs. “Hell yeah, I loved drugs! I looovvved them.” This doesn’t quite communicate the depth of his passion, though, so he searches the ceiling and says “I mean, I LOVED them. I loved them more than me. I loved drugs. Loved them. Loved getting them, having them, using them.”

Murray was a stuff-the-glass-pipe-with-meth-and-crack addict and when he says he was in love with drugs, he’s not speaking in metaphors. He loved drugs, he says, “more than my wife. More than my daughter.”

He’s right to say it this way, too, because love itself is an addiction. That explains why we become obsessed with a new love, why breaking up is so tough, why we drunk dial our exes, why we stay in relationships long after the thrill is gone.

“Each encounter was accompanied by a rush of euphoria -- new experiences, new pleasures, each more exciting than the last…. Other interests suddenly became less important as more time was spent pursuing the next joyful encounter.”

Is this describing new love, or drug use?

As Larry and a colleague, James Burkett, wrote in the journal Psychopharmacology, published online last month, it could be either. The behavior is the same because the brain mechanisms are remarkably similar.

It starts with something called reward-based learning. When Murray initially used cocaine, “it seemed like it gave you that sense of energy, excitement. And talk about social lubricant! Man, it’s almost like you get a straight adrenaline shot to the ego, and all the sudden women I’d never say a word to, I’m talking to them.”

Naturally, he wanted those good feelings again and again. Every time he used, the brain’s mesolimbic dopamine system reinforced a positive motivation to seek the reward, and soon, even the mere presence of his pipe could elicit pleasure, leading to impulsive drug using.

New love follows the same course. It feels good, so we want more. Any reminder of our lover can spark motivation to be with them. And then one night we find ourselves in flagrante delicto on the hood of a 2003 Ford Focus.

Our pre-frontal cortex (PFC), may try to tell us that risking arrest for indecent exposure is a bad idea, but it has to shout over the appetite being generated by the brain’s reward system. That system can be so powerful it can effectively mute the PFC.

That kind of giddiness can be fun, but, says George Koob, one of the world’s leading experts in the neurobiology of drug addiction, and a scientist at the Scripps Research Institute in San Diego, “unfortunately, the cycle can’t be maintained.”

Whether the stimulus is love, or drugs, the brain adapts. It physically changes, reconfiguring the mesolimbic dopamine system. In addition, a stress-related neurochemical called corticotrophin-releasing factor (CRF) rises.  

“Liking” changes to “wanting.” Rather than a positive motivation, we’re now under the thumb of “negative reinforcement.” A drug addict no longer likes the drug, he wants it. “What you are worried about is feeling terrible when you are not on the drug,” Koob says.

Likewise, the exuberant thrill of a new relationship fizzles, but separation feels painful.

A German scientist named Oliver Bosch explored this idea when he visited Larry’s lab at Emory University in Atlanta. Using prairie voles, small rodents that usually form lifelong socially monogamous bonds, Bosch “divorced” males by taking them away from their female mates. He placed these males in water for what’s called the “Porsolt-swim test,” a common maneuver used to detect depression, stress, and anxiety.

A mentally healthy vole will paddle like crazy trying to escape. But the males who’d been “divorced” simply floated, as if they didn’t care if they lived or died, a reaction called passive-stress coping. Other tests showed the same kind of effect.

“When the separation takes place, this is what causes the animals to feel so bad,” Bosch says.   

This exact reaction also occurs in lab animal addicts deprived of drugs.

“I compare it to a rifle,” Bosch explains. “As soon as they form a pair bond, the rifle is loaded with a bullet. But the trigger isn’t pulled unless there is a separation.” This may explain why couples stay together long after the giddiness is gone: they’re “hooked” on their partners.

This system is an important element in monogamy. We stay together because we’ve got a gun to our head.  

Koob agrees. “Drug addiction and love are absolutely parallel,” he declares without a hint of doubt.

Brian Alexander is a frequent contributor to TODAY.com and NBCNews.com. This post is excerpted and adapted from "The Chemistry Between Us: Love, Sex, and the Science of Attraction," published by Current, an imprint of Penguin Group (USA). Copyright (c) Larry J. Young and Brian Alexander, 2012.

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