Love Is the Drug...

Passion is born in the brain's addiction center, study finds

FRIDAY, June 10, 2005 (HealthDay News) -- In love songs, passion lifts you up or cuts you like a knife, wreaking havoc with your emotions as it tosses logic out the window.

But what if love isn't about emotion at all? What if it isn't even about sex?

That's exactly what a team of scientists is discovering as they watch new love literally blaze its trail across the living brain. Using real-time MRI brain images of people in the initial throes of passion, they're finding that love originates far from the brain's logic center, its emotional nexus and, perhaps most surprisingly, its centers of sexual desire.

In fact, love may vie for the same real estate in the brain as drug addiction.

"There's this general craving-and-desire system that's engaged, only in this case the desire isn't for money or a drug or power or freedom. The desire is for merging with another person," explained co-researcher Arthur Aron, a professor of psychology at the State University of New York at Stony Brook.

"Furthermore, the neural systems engaged by sex and love are really quite distinct," he added. "This is really the first unambiguous evidence that they really are separate systems."

According to Aron, the findings help explain instances where people fall in love with people they aren't even sexually attracted to; or why others can feel equally strong, sudden emotion for a newborn child or even God.

In their study, published in the June issue of the Journal of Neurophysiology, Aron and his co-researchers used functional MRI to watch the real-time brain activity of 17 college students (10 women, seven men), all of whom were in the early weeks or months of new love.

Brain activity was monitored under two conditions: first, when the participants were given a picture of their beloved to gaze at, and then when they were asked to look at the picture of an acquaintance.

Staring at their lover's image "lit up a lot of brain areas, but the two most important ones were, first, the ventral tegmental area -- a little factory near the base of the brain that makes dopamine, a natural stimulant -- and the caudate nucleus, a large organ in the middle of the head that looks a bit like a medium-sized shrimp," said co-researcher Helen Fisher, an anthropologist researcher at Rutgers University.

"Both of these areas are part of the reward system in the brain -- the dopaminergic system associated with very focused attention, elation, energy, craving, motivation," she said. Based on this evidence, "we feel now that romantic love is a drive, not an emotion. It's a basic mating drive."

In fact, the brain's emotion centers tended to light up only as new love grew old, she said. "When we took a look at those who had been in love between eight to 17 months, in fact we did see new activity in regions associated with the emotions," she said.

But early love, rooted as it is in the caudate nucleus, is all about addiction.

"It is a drug addiction," Fisher said. "It's certainly got some of the main characteristics of drug addiction -- as with drugs, once you fall in love you need that person more and more, so much so that, after a while, you have to marry them. There are other things, too -- real dependence, personality changes, withdrawal symptoms."

And just like the need for cocaine or heroin, love can make people do crazy, sometimes dangerous things.

"It's a major source of depression, suicide, stalking, homicide," Aron pointed out. "Of course, on the more positive side, it's a major source of overcoming depression and making life more meaningful, too."

The findings make sense to Paul Sanberg, a professor of neuroscience at the University of South Florida whose early work concentrated on the caudate nucleus. "From a behavioral point of view -- having been in romantic love in my life -- I can say it is addictive," he said. "And from an anatomical point of view, they're talking about dopamine."

Most intriguing was the finding that romance and sex are not neurologically linked, although behaviorally they usually go hand-in-hand.

"Sex is only a tiny part of love," said Fisher, also the author of Why We Love. "You want to have sex with the person, but much more than that you want them to call you, to write, to return your love, to be loved back."

People in love often describe the experience as an "expansion" of self, she said, a more general merging with the other: "Your edges get very porous -- you lose yourself in order to include the other person."

And when that person leaves, real withdrawal -- heartache -- sets in. In a second, as-yet-unpublished experiment, the researchers conducted functional MRI scans on individuals who had been recently dumped by the objects of their affection.

"These people were in terrible pain," Fisher said. Again, areas of the brain linked to passionate love lit up on fMRI when participants were given a picture of the loved one. "We all know that when you are dumped you just love the person harder -- I call that 'frustration attraction,' " she said. "And that reward system in the brain, when it realizes that the reward is delayed in coming in, it still sustains its activity."

According to Aron, the next step is to find out what happens to brain activity as new love passes away and settles into a more secure, albeit less intense, emotional realm.

"We're hoping to get funding to do studies where we follow the same people, keep scanning them every few months and see how things change," he said.

The team is also gathering a study group of people who claim to feel great passion for their partner 10, or even 20, years into the relationship.

"They aren't common, but enormously interesting," Aron said. "How can it be that you've been together that long and you're still intensely in love with them?"

Fans of Romeo and Juliet and Wuthering Heights may worry that all this neuroscience will drain the poetry out of passion. But Fisher says there's no reason to fret.

"Look, you can know every single ingredient in a piece of chocolate cake," she said. "Then you can sit down with that cake, and taste every bit of its poetry and just revel in the joy of it."

More information

For more on the psychology of relationships, visit the American Psychological Association.

SOURCES: Arthur Aron, Ph.D., professor, psychology, State University of New York, Stony Brook; Helen Fisher, research professor, department of anthropology, Rutgers University, New Brunswick, N.J.; Paul Sanberg, Ph.D., professor, neuroscience, and director, Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa; June 2005, the Journal of Neurophysiology
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