The medical phenomenon of love

Since the days of Romeo and Juliet, the notion of love is almost always bound to some tragic and elaborate, you-jump-I-jump conundrum. In the headiness of infatuation, pulses race, knees go weak, and you start speaking gibberish.

Despite the thousands of love songs and sonnets that these feelings may have inspired, the unpalatable truth is that falling in love, is in some ways, indistinguishable from severe pathology.

Some say that love hurts, and in the world of science, it is more than just a metaphor. Love does indeed impact our bodies in measurable ways, sometimes putting us in the most hopeless and unfortunate of circumstances.

While falling in love is often deemed an affair of the heart, research shows that these intense, romantic feelings actually come from the brain.

Scientists believe that dopamine, the brain's pleasure chemical, is the culprit behind love's emotional roller coaster, on which you feel deliriously happy one minute, and anxious and desperate the next.

Dopamine, the key to our experiences of pleasure and pain, has been linked to desire, addiction and euphoria. Taking opioid drugs such as cocaine has a similar effect on dopamine as love. The prime neurotransmitter that makes you angry and upset, and motivates you to act irrationally and impulsively is also dopamine.

It comes almost as no surprise that research has suggested that events occuring in the brain when we fall in love bear similar traits to mental illness. This is probably the part where you find yourself falling in love with a vampire who sparkles in the sun.

Enter the drama mama, the frantic text-messaging, and the obsessive-compulsive I miss-you rhetoric while caught up in the vertigo of romantic love.

That said, dopamine is not an enemy of the system. Without dopamine, we would have trouble moving as dopamine is needed for something as fundamental as controlling motion. People with Parkinson's disease have precariously low levels of dopamine.

Of course, the sex hormones oestrogen and testosterone play an integral role in falling in love, because without them, we might never venture into the arena of romantic love to begin with.

Dopamine triggers the production of testosterone, which also plays a major role in the sex drives of both men and women. That's when sexual attraction kicks in.

Helen Fisher, a leading expert on the biology of love attraction, has proposed that people fall in love in three stages:

1. Lust (driven by the sex hormones or sex drive)

2. Attraction (the early stage of intense romantic love)

3. Attachment (a deep bond with a long-term partner)

Fisher believes that love, specifically romantic love, is as important as maternal instinct or the sex drive. It originates from parts of the brain associated with motivation, she says.

However, while you can turn off the sexual urge, it is very hard to turn off romantic love, Fisher suggests. "In the grip of romantic love, you can commit suicide or homicide, or stalk somebody, or fall into intense clinical depression."

Love makes the world go round, but it also crushes and destroys us, reducing the best of us into defenceless crybabies. It gives literal meaning to the term love-sick.

Poets, novelists and songwriters have described it in countless flourished turns, but when it comes to falling in love, it appears that we are really at the mercy of our biochemistry.

You know that feeling you get when you catch sight of your beloved and you feel like your heart might just thump out of your chest? That's actually a biological response that results from an adrenaline rush, says Dr Reginald Ho, a cardiac electrophysiologist and associate professor of medicine at Thomas Jefferson University Hospital in Philadelphia, Pennsylvania, US.

It goes something like this: You see your sweetheart and your brain sends signals to the adrenal gland, which secretes hormones such as epinephrine - otherwise known as adrenaline, which starts us sweating and sets our hearts racing. Epinephrine is a hormone and neurotransmitter that has many functions in the body, including regulating heart rate, blood vessel and air passage diameters, and metabolic shifts.

Epinephrine release is also a crucial component of the fight-or-flight response, creating the elusive adrenaline high.

This response is similar to an elevated heart rate while running on a treadmill, but minus the benefits of exercise (and no, it certainly won't help you lose weight).

Worse things have been known to hound those in the throes of romantic love. People have been known to become obsessed and even go as far as stalking their partners.

This is no thanks to the plunge in the chemical, serotonin, a key hormone regulating our moods and appetites. Serotonin is popularly thought to be a contributor of feelings of well-being and happiness.

Researchers at University College London, UK, have discovered that people in love have lower levels of serotonin. These lower serotonin levels are similar to those found in people with obsessive-compulsive disorders, possibly explaining why people experiencing infatuation cannot think of anyone else and may even verge on being "obsessed" with their partners.

This is probably also the same reason why you can't stop checking your phone for new messages every five seconds.

An overwhelming sense of dejection sinks in at the sight of an empty screen, to be replaced by a sudden burst of elation when your long-awaited reply finally arrives!

Given the circumstances, it does not take a whole lot of reasoning to arrive at the plausible hypothesis that people with low brain levels of sorotonin also tend to become extremely jealous in their relationships.

Jealousy is one of the biggest signs of falling in love, and possibly the most prominent one. Often, it can wrench apart relationships that were going on just fine.

Jealousy comes from the anticipation of losing something, and anticipation can be an awful thing. People have been known to be jealous of their friends, co-workers, and even their siblings. But romantic jealousy probably stands out as the most frequently experienced type of jealousy, and is likely the most destructive.

There is a reason why jealousy is referred to as "the green-eyed-monster". Jealous people frequently act on their feelings, here and now, regardless of future consequences, which can lead to the most regrettable of actions.

Extremely jealous people may have difficulties hiding their obsessive thoughts from their partners. They may be accusing their partner of having an affair or wanting to have one, despite having no concrete evidence or reason behind it.

It can become a self-fulfilling prophecy, and will likely ensure that your ex will hide behind the bushes the next time they run into you.

More alarmingly, these green-eyed folks may even engage in criminal activity or turn to self-medication with alcohol or drugs. And let us not get into the grotesque details about couples who end up hurting their partners.

Most people, in spite of the hullabaloo that goes on in their heads when they fall in love, are unlikely to cross that line. But it would be wise to hold back just a little the next time you intend to bombard your crush's inbox with needy or emotional messages.

Just remember, it could be the decreased serotonin talking.

There are many researchers who believe that an imbalance in serotonin levels may also influence mood in a way that could lead to depression.

This perhaps provides an explanation as to why some people are convinced that they no longer have a reason to live in the event of unreciprocated love.

But although it is widely believed that serotonin deficiency plays a role in depression, there is no way to measure its levels in a living brain.

Blood levels of serotonin are measurable, and have been shown to be lower in those suffering from depression, but there is no concrete evidence that blood levels reflect the brain's level of serotonin.

Also, it is not known whether the dip in serotonin causes the depression, or if depression causes serotonin levels to drop.

But fret not, there is hope yet for the love-sick. As with most things in life, the roaring flame of dopamine-fueled euphoric love will eventually settle into the smouldering embers of a more sustainable and long-term oxytocin-based relationship.

This happens as the novelty and mystery of a new relationship fades into routine.

Oxytocin is a powerful hormone released by the hypothalamus gland during childbirth, and also helps with breast milk expression. Oxytocin cements the bond between mother and child.

When we hug or kiss a loved one, oxytocin levels shoot up. The theory goes that while in a relationship, oxytocin is released by both sexes during orgasm, and is thought to promote bonding when adults are intimate. So technically, the more sex a couple has, the deeper their bond becomes.

Oxytocin levels can eventually decrease as well, as the frequency of the very acts that promoted the bond such as hand-holding, hugging, caressing and sex dwindles over time.

Stress can also have an impact on oxytocin levels, particularly in women.

Doing novel things together, such as trying out a new restaurant or going on a trip, not only creates an exciting twist to your routine, but also helps to increase dopamine levels in the brain. A weekly date-night is a good place to start.

Meanwhile, bond-promoting gestures such as hugging or cuddling in bed can also help increase oxytocin levels, which lowers blood pressure and is good for heart health.

Despite the odds and the various bizarre biological responses our bodies go through when we fall in love, it seems that the elusive happily-ever-after ending can exist after all. But only for those who persevere.