The Mysteries of Love

Can Love Be Addictive?

Love plays havoc with your body chemistry, causing you to act like an addict bent on scoring her next fix. Studies have found, for instance, that serotonin levels decrease by up to 40 percent in the newly smitten, causing some to show signs of obsessive-compulsive disorder, a condition associated with low serotonin―which is why you can’t seem to get the other person out of your head. Additionally, cortisol, a stress hormone linked with the fight-or-flight response, is released, so you’re constantly on high alert. Sound familiar?

Research published by a team that included Brown and Fisher found that people who had recently fallen in love showed strong activity in the area of the brain that produces and receives dopamine, a neurotransmitter associated with addictive behavior whose activity increases when you expect to receive a reward. Gamblers and drug addicts experience similar dopamine activity. “You’re not supposed to be satisfied,” explains Fisher. “You’re supposed to be driven so that you can win the person and eventually stabilize your internal chemistry.”

When a relationship ends, you experience symptoms that are similar to an addict’s withdrawal. Your dopamine levels go down, so your mood suffers. Your serotonin levels remain low, so your obsessive-compulsive disorder symptoms may not go away. In response to these imbalances, some scientists believe, risk-taking tendencies go up. “When you can’t have someone but you’re not willing to accept that, you try harder and become more extreme about it,” says Fisher. Paradoxically, she says, this compulsive behavior may help you move on faster: “Either you win the person back or you drive him away.”

What Makes People Commit?

Humans are hardwired to stick together. Intimate relationships trigger the production of oxytocin and vasopressin, chemicals that scientists have nicknamed “cuddle hormones.” A mere touch from a loved one can elevate their levels, and after sex they flood the system. “We think of these hormones as playing an important role later on in the relationship, when you really know the person’s flaws,” says Brown.

Why Are Some More Reluctant to Commit Than Others?

Gene variation may be partly to blame. Scientists at Emory University, in Atlanta, looked at the effect of vasopressin in two closely related kinds of rodents―the prairie vole and the meadow vole. Like humans, the prairie vole is one of the 3 percent of mammalian species that form monogamous pair bonds. The meadow vole doesn’t. But when male meadow voles were injected with a gene responsible for releasing vasopressin receptors, they immediately lost their wanderlust, paired up, and settled down.

The study’s researchers think the number of vasopressin receptors an individual has could lay the foundation for his propensity to commit. “There’s something at work with a couple that stays together for 50 years, bad years included,” says Melvin Konner, M.D., a professor of anthropology and behavioral biology at Emory, who wrote a commentary on the experiment. “It’s hard to imagine that it’s just a question of compatible personalities or strict beliefs.”