Addicted to Love

Your heart races, your sense of time disappears, and your thoughts revolve around only one person – when we are in love, the world is turned upside down. “Love is a serious mental illness,” Plato is said to have remarked. Anthropologist Helen Fisher of Rutgers University in New Jersey, one of the most renowned researchers in the field of love, puts it more conciliatorily: “Romantic love is one of the most powerful emotions in the world”.

But what actually happens to us when we fall in love? Researchers like Fisher have been searching for an answer to this question for several years by studying the brain activity of study participants who are in love. In 2000, neurobiologists Andreas Bartels and Semir Zeki from University College London sent 17 people who were newly in love into an MRI scanner and measured their brain activity while the subjects looked at photos of their loved ones and friends.

The results were astonishing: when the subjects looked at pictures of their loved ones, different areas of the brain were active than when they looked at their friends. Particularly interesting was the activity of the hippocampus, Nucleus caudatus, putamen, and Nucleus accumbens These areas of the brain play an important role in the brain's reward system.

However, brain regions responsible for the Perception of fear or for the critical evaluation of others were less supplied with blood than usual when looking at the loved one. “It is not surprising that we are often surprised by the choice of partner that others make and wonder if they have lost their minds,” writes Zeki. "In fact, they have. Love is often irrational because rational decisions are suspended or no longer applied with the usual rigor”. Perhaps love really does make you blind.

The altered Perception of the beloved is also due to a very special cocktail of hormones and neurotransmitters that are released in the brains of people in love. Dopamine plays a central role in this. The neurotransmitter, known to many as the “happiness hormone,” makes us feel good and is associated with reward, euphoria, but also addiction. In fact, in their studies, Zeki and Bartels found that people in love or those who are infatuated react to images of their loved ones in the brain in a similar way to cocaine addicts or alcoholics reacting to an image of their drug. “When you interpret the data, you can definitely compare love to an obsession or addiction,” says Andreas Bartels, who now works at the Center for Integrative Neurosciences at the University of Tübingen.

According to Helen Fisher, lovers react to being abandoned in the same way as addicts going through withdrawal: they suffer pain, become depressed, and try intensely to win back their beloved partner. This is because the reward center is still active in lovers who have been abandoned, as Fisher recently demonstrated using brain scans of abandoned partners: “The reward system for desire, for wishes, becomes more active when we don't get what we want”, says Fisher.

In addition to dopamine, however, two other hormones play an important role: vasopressin and oxytocin are also released in greater quantities in people who are in love. Both are considered bonding hormones, among other things. Vasopressin has mainly been studied in animals in this function. There, a connection with bonding ability in males is suspected.

The function of oxytocin is better understood. The Hormone reduces anxiety and stress and helps us to trust other people. Or not – oxytocin primarily strengthens bonds within one's own group, while it can exclude others. But at this point, we are talking about love. And here, oxytocin also ensures the intimate closeness of parents and children and is responsible for the bond between couples. It is released in greater quantities when mothers breastfeed their children, when we experience pleasant touch or an orgasm – or when we look into the eyes of a loved one. “It is assumed that oxytocin triggers a certain learning ability, but one that is specific to social learning,” explains Bartels. There is a close interaction with the happiness hormone Dopamine: “The child or partner is positively associated, triggers a reward in the brain, and you bond with the individual”.

However, it is also true that hormones cannot be reduced to one single effect. Vasopressin, for example, is involved in aggression, especially in animals. Even the “cuddle hormone” oxytocin has different effects depending on the context, such as whether or not a person is a member of our group –  or not. The social salience hypothesis attempts to do justice to this. According to this hypothesis, it is a matter of strengthening the Perception of social stimuli, but with different effects depending on the context.

However, scientists have not yet been able to clarify the criteria we use to select the people we fall in love with. The only thing that is certain is that romantic love is a fundamental biological mechanism that helps us form long-term partnerships and raise our children. “Love is a need, an urge like hunger or thirst”, says Helen Fisher. “It is impossible to eradicate it”.

Love – reduced to evolutionary tasks, Hormone surges, and brain activity: Are researchers demystifying the most beautiful feeling on earth with their studies? Andreas Bartels, at least, continues to believe in the magic of love: “Knowing how it arises does not diminish the feeling,” he says. “We would be no less fascinated by a Picasso painting if we saw how he painted it”.

First published on December 20, 2011
Last updated on December 9, 2025