It seems there are three stages of love.
Stage 1: LUST
Lust is driven by the sex hormones testosterone and oestrogen. Testosterone is not confined only to men. It has also been shown to play a major role in the sex drive of women.
Stage 2: ATTRACTION
This is the truly love-struck phase. When people fall in love they can think of nothing else. They might even lose their appetite and need less sleep, preferring to spend hours at a time daydreaming about their new lover.
In the attraction stage, a group of neuro-transmitters called 'monoamines' play an important role:
· Dopamine - Also activated by cocaine and nicotine
· Norepinephrine - Otherwise known as adrenalin. Starts us sweating and gets the heart racing
· Serotonin - One of love's most important chemicals and one that may actually send us temporarily insane
Stage 3: ATTACHMENT
This is what takes over after the attraction stage, if a relationship is going to last. People couldn't possibly stay in the attraction stage forever, otherwise they'd never get any work done!
Attachment is a longer lasting commitment and is the bond that keeps couples together when they go on to have children. Important in this stage are two hormones released by the nervous system, which are thought to play a role in social attachments:
· Oxytocin - This is released by the hypothalamus gland during child birth and also helps the breast express milk. It helps cement the strong bond between mother and child. It is also released by both sexes during orgasm and it is thought that it promotes bonding when adults are intimate. The theory goes that the more sex a couple has, the deeper their bond becomes
· Vasopressin - Another important chemical in the long-term commitment stage
Does Love Drive You Mad?
In 1990, a study in Italy indicated that people who have recently fallen in love have some of the symptoms of 'Obsessive Compulsive Disorder' or OCD. People with OCD behave obsessively about certain things. They might be constantly washing their hands, or need to continually check to see if the door is closed.
Does love make you sad?
Rather than making you happy, love could actually make you depressed. One symptom of OCD appears to be unusually low levels of the neuro-transmitter 'serotonin'. Low levels of serotonin have been associated with anxiety and depression. Italian students who claimed they had recently fallen in love were found to have serotonin levels 40% lower than their peers.
However, the biochemical effect of falling in love didn't last forever. When the same students were tested after their relationship was a year old, their levels had returned to normal. One author of the study has suggested that we require this chemical response for relationships to survive. After all, we'd have to be mad to fall in love wouldn't we?
Another interesting finding is that people with low serotonin levels tend to have a lot of sex. If men have a particular version of a gene known as the 'serotonin transporter', they will have lower levels of serotonin in their brains. They tend to be more anxious than other men and also more sexually active.
Love on the brain
Brain imaging techniques have been put to use in the name of love. Andreas Bartels and Semir Zeki at University College London used functional Magnetic Resonance Imaging (fMRI) to take pictures of the lover's brain.
Whilst inside the scanner, loved-up students were shown pictures of their new flame. They were also shown images of platonic friends of the opposite sex. Zeki and Bartels were struck by how clear cut the pattern of brain activity was when students were looking at their new love.
Four areas of the brain became active, and one area noticeably inactive, when the students had love on their mind. The active areas include one responsible for 'gut' feelings and one that is known to respond to euphoria-inducing drugs. The lights go off however, in the prefrontal cortex, an area that is overactive in depressed patients.