science of love

mmm...just curious because my friend told me that to love means to hurt... ?!@#$
Really?

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?
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(www.bbc.co.uk)