Health & Sex

Love Is All in Your Head -- Or Is It in Your Genes?

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When we speak of the chemistry of love, it's not just an idle expression. Different chemicals in the brain, or neurotransmitters, play different roles at each stage of the mating game.

"There are three different types of love -- lust, romantic love, and long-term attachment -- each associated with different neurotransmitters, all hardwired into the brain," Helen E. Fisher, PhD, tells WebMD.

"Lust, that emotion that chases us out of the house and drives us to find a partner, is related to bursts of testosterone," says Fisher, a professor of anthropology at Rutgers University in Newark, N.J.

Romantic love, she says, is related to abnormalities in the neurotransmitters serotonin, dopamine, and norepinephrine, making it biochemically similar to obsessive-compulsive disorder, a psychiatric illness where thoughts of a single subject dominate the patient's life.

Fisher has interviewed romantic lovers who tell her that they spend 85% of their waking moments fantasizing about their loved one. "In romantic love, we can't stop thinking about the person we're in love with," she says.

When you're in love, it's in your blood as well as in your head, according to research from the University of Pisa in Italy. Subjects falling in love resembled patients with obsessive-compulsive disorder in terms of neurochemical changes involving platelets, those blood cells involved in making blood clot and wounds heal.

"I did not discover why we fall in love, but only that romantic lovers resemble patients with obsessive-compulsive disorder in this platelet abnormality, which may underlie the similar thought process," researcher Donatella Marazziti, MD, tells WebMD. "This is only a small tile in the complex mosaic of love, which is certainly also something more than mere biology."

In romantic love, we feel elated and giddy, and can't sleep or eat, because of increased levels of dopamine and norepinephrine. "This phase evolved so we could distinguish between potential partners," Fisher says.

When we're in love, dopamine, nicknamed the "pleasure chemical," gives us a "high," according to James H. Fallon, PhD, a professor of anatomy and neurobiology at the University of California at Irvine.

"Dopamine is the great motivator in the brain that is absolutely necessary to act ... to walk over to the person we've just seen and start a more serious approach," Fallon says.

Dopamine can be stimulated artificially by alcohol and drugs. Along with other brain chemicals, it also gives us those physical clues that we're falling in love -- heart racing, pupils dilating, and a light sweat -- turning on pheromone production.

Genetic differences in body chemistry may create different pheromones, so that prospective mates may be subconsciously "turned on" or "turned off" by subtle chemical messages. Commercially produced pheromones are therefore unlikely to have universal appeal, according to Fallon.

Another spirit in the heady cocktail making us intoxicated with romantic love is phenylethylamine (PEA), according to Hector Sabelli, MD, PhD, a researcher at the Chicago Center for Creative Development in Illinois. "I believe that PEA may be the hormone of libido, but there's only circumstantial evidence at this point," Sabelli tells WebMD.