Having Good Chemistry: How Being in Love Changes The Brain

It would be just about impossible to write a list of every song or poem ever written that talks about the pain of a broken heart — the inevitable condition that comes with lost love. It’s a hard thing to carry and a hard thing to get over — but rarely do you find love ballads that mention the brain, the very organ that drives us to seek out romantic relationships in the first place, playing a major role in how we select romantic partners and are forever changed as a result of falling in love. Evidently, love affects our brain, and in some ways its thrill changes the structure permanently.


“We know that primitive areas of the brain are involved in romantic love,” says Jacqueline Olds, an associate professor of psychiatry at Massachusetts General Hospital in Boston. “These areas light up on brain scans when talking about a loved one. These areas can stay lit up for a long time for some couples.” Her father, James, is credited with the discovery of the ventral tegmental area of the brain — which makes up a portion of the brain’s reward circuitry. It links to areas of the brain that are quite primitive in our evolutionary journey — connecting to the amygdala, which we associate with fear, as well as the nucleus accumbens and the hippocampus, which play a role in temperature regulation and production of the neurotransmitters serotonin and dopamine.

The sensation of falling in love is the result of the spike in these chemicals. A heavy burst of dopamine is probably the reason you find your new romantic partner intoxicating — their looks, their scent, what they wear. The rush you may experience when your significant other is on their way home from work is similar to the warm, mellow happiness you get from consuming your favorite alcoholic drink — both are rewards that your brain learns to seek out.

During the first few dates, the stress hormone cortisol also increases (the driving force behind your sweaty palms and racing heartbeat). The increases of cortisol cause the levels of serotonin in your bloodstream to drop, setting the stage for obsessive thoughts about your significant other. Low levels of serotonin have been associated with obsessive compulsive disorders — when certain actions or routines comfort the individual without a logical reason. A particularly eventful date night is one you’ll likely relive again and again, recalling specific words that were said and the exact feelings you felt.

Amid the joyous feelings we often associate with falling in love, something else is taking place in our brains. You may feel a bit surer of yourself — and care less about what your friends think reinforcing the notion that you and your significant other are the only two people in the world.

These feelings are due to chemical changes in the brain. The connection from the nucleus accumbens to the amygdala is deactivated. While this curbs the fear and inhibition that might normally hold you back from pursuing a romantic interest, it also takes away your sense of social judgement — it’s why you don’t see your partner’s shortcomings until a year or two into the relationship; sometimes these imperfections are minor, other times they are flaws that make you wonder what you saw in that person to begin with. It’s also why getting distracted is easy and keeping focus is hard at this point in your relationship — too much passionate love has been linked to a decreased individual efficiency in cognitive control.

Even in the case of a minor flaw, it’s not always easy to break things off. This is due in part to other chemical signals in the brain — oxytocin, which promotes feelings of security and contentment when your significant other is around, and vasopressin, which promotes pair-bonding. Along with the fear of uncertainty about what happens after it’s over, you may see yourself rationalizing your decision to stay, in part because of these chemicals.


The increase in oxytocin and vasopressin (following the surge of dopamine and cortisol) explains why the passion seems to fade while attachment to your partner grows. Often, these chemical changes can stay in the brain for a long time. A 2011 study conducted by Drs. Bianca Acevedo and Arthur Aron of Stony Brook University took functional MRI images of 17 people (10 women, seven men) who had been married for an average of 21 years, or more, and who had described themselves as “happily married” and experiencing “intense romantic love.” The researchers found that the ventral tegmental area showed the same activity patterns as test subjects in another study who reported being madly in love with their partner of a year or more.

This article was originally published in the Winter 2019 issue of Brain World Magazine.

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