A Valentine's Week Special: The chemistry of love

"Love and obsessive-compulsive disorder could have a similar chemical profile," says professor of psychiaty Donatella Marazitti, who studies "the biochemistry of lovesickness." Now there's a topic to ignite the passions, one explored in this month's National Geographic magazine.

The key apparently is two chemicals:serotonin and dopamine. Serotonin -- "perhaps our star neuro-transmitter" -- the one that is altered by drugs like Prozac -- is what quite literally gives our passions real feeling. People with obsessive-compulsive disorder apparently have an imbalance of serotonin; so too do people in the grip of love.

Translation: love and obsessive-compulsive disorder could have a similar chemical profile. Translation: love and mental illness may be difficult to tell apart. Translation [says the National Geographic]: Don't be a fool. Stay away.

If you take advice like that last you're probably dead already. And if you take the science of the idea, you can see that our emotions are very real things. "Sex is emotion in motion," declared Mae West -- those emotions really do have us in thrall. We're wired for love and the obsession that goes with it. Don't deny it, celebrate it. When anthropologist Helen Fisher used an MRI machine to investigate those who do celebrate it , "what Fisher saw fascinated her":

When each subject looked at his or her loved one, the parts of the brain linked to reward and pleasure -- the ventral tegmental area and the caudate nucleus -- lit up... Love lights up the caudate nucleus because it is home to a dense spread of receptors for a neurotransmitter called dopamine, which Fisher came to think of as part of our own endogenous love potion.

In the right proportions, dopamine creates intense energy, exhilaration, focused attention, and motivation to win rewards. It is why, when you are newly in love, you can stay up all night, watch the sun rise, run a race, ski fast down a slope ordinarily too steep for your skill. Love makes you bold, makes you bright, makes you run real risks, which you sometimes survive, and sometimes you don't...

Dopamine, says British psychologist Dr John Marsden "has similar effects on the body and mind as cocaine or speed. 'Attraction and lust really is like a drug. It leaves you wanting more'." Sounding familiar, anyone? "My love is chemical." "Love is the drug." "Love Sick." Turns out the songwriters were right all along. "What's your drug of choice then?" Love. Romantic Love.

It's our nature to fall in love, to be obsessed with love, to lose ourselves in love. "To fly in love on many splendoured wing/ Towards what hot sun may/ Roast my own illusions/ And melt my very soul." So said the poet, Amen.

Now, as I suggested last when giving my $2 on the nature-nurture debate, we're not entirely slaves to our nature, even on the subject of love. "If that was all we had -- if nature and nurture were the whole of the debate -- then that would be it, and we would be ruled only by our animal functions." There is still the large matter of our free will, of choice, which involves in part who we fall in love with, and what we allow ourselves to do about our passions. More on that another day. Until then keep up your obsessions, and enjoy the weekend.

LINKS: So what, really, is this thing called love - National Geographic [introduction only]
Video: That thing called love - National Geographic
Love is the drug, scientists say -- BBC News
Nature v Nurture - character is all - Peter Cresswell