A wise sage named Kesha once said "Your love is a drug." It would seem she's done her research.
Researchers over the past few decades have examined the brains of those struck by cupid's arrow and unearthed some remarkable findings, revealing just how potent an effect love and attraction have on brain chemistry.
"Falling in love causes our body to release a flood of feel-good chemicals that trigger specific physical reactions," Dr. Patricia Mumby, a professor in psychiatry and behavioral neurosciences at Loyola University Chicago's Stritch School of Medicine, told Science Daily. "This internal elixir of love is responsible for making our cheeks flush, our palms sweat and our hearts race."
The love drug
So what causes those physical reactions to an emotional stimulus? Love inhibits the uptake of three neurotransmitters — dopamine, norepinephrine and serotonin — which makes you feel like everything is awesome. By preventing neurons from absorbing these neurotransmitters, they hang out in the brain outside the cells instead (when they're taken up by neurons, their impact is negated).
So an increase in extracellular dopamine, norepinephrine and serotonin makes you feel good. It's a physical response that isn't far off to the body's response on — surprise, surprise — cocaine.
You get a bump in norepinephrine, for example, because your loved-up brain tells the adrenal gland atop your kidney to start pumping it out when you've gone starry-eyed. At the same time, your brain also tells your adrenal glands to pump out adrenaline and epinephrine.
This explains why your heart starts to race and your palms start to sweat and your mouth becomes dry and maybe you feel a little sick when you're around the person you love.
Pleasure and reward
A lot of this brain activity goes down in two reward and pleasure centers, known as the caudate nucleus and ventral tegmental area, a 2005 study which examined fMRI brain scans of 2,500 college students in love revealed.
The study was led by renowned anthropologist Helen Fisher, who delivered a TED Talk on what love does to the brain.
"Two of the brain regions that showed activity in the fMRI scans were the caudate nucleus, a region associated with reward detection and expectation and the integration of sensory experiences into social behavior, and the ventral tegmental area, which is associated with pleasure, focused attention, and the motivation to pursue and acquire rewards," the Harvard Mahoney Neuroscience Institute wrote in its explanation of the study.
That explains why you're always left wanting more, making falling in love feel a bit like an addiction.
It's an obsession
But the early stages of falling in love can also make you a little crazy.
When you start falling for someone, there's a rise in cortisol, the stress hormone — which would explain all the anxiety: Did he mean to brush hands? Does she like me, too? Does this shirt make me look hot enough? Am I visibly sweating?
And in the very early, beginning stages, as the cortisol rises, serotonin levels actually decrease — unlike, as explained above, when it surges during the next phase of love, along with dopamine and norepinephrine. People with obsessive compulsive disorder also have lower levels of serotonin.
So, when you're crushing hard, your brain sort of replicates that of someone with OCD, which is why it can feel like an obsession.
And then there's the attachment thing
When you have sex or are physically touched (by someone you like or love), it releases the hormones vasopressin and oxytocin, which are also released during the last phase of love, the "attachment" phase.
These hormones enhance feelings of attachment and make two people in love feel connected on a deeper level.
And these powerful hormones are released in expectant mothers and immediately after their babies are born, because they help trick people's brains into developing a human attachment with another person.
Another thing that augments this sense of connection is lowered levels of testosterone in men and higher levels of testosterone in women who are in love.
"Men, in some way, had become more like women, and women had become like men," Donatella Marazziti, a specialist in psychiatry at the University of Pisa in Italy and who's conducted research on love's influence on the brain, told New Scientist. "It's as if nature wants to eliminate what can be different in men and women, because it’s more important to survive [and mate] at this stage."
So, in sum, falling for someone includes feeling sweaty, like you've developed an addiction, like you're on cocaine and as though you have OCD: What's not to love?