BACK in 1965, Cat Stevens wrote The First Cut is the Deepest. It turns out he was right. New research from a joint American and Australian study has found that teen love feels life-changing because the combination of a developing brain, surging hormones and a lack of identity leads to adolescents ''merging'' so they feel not quite whole when apart.
A psychologist, Carl Pickhardt, of the American and Texas psychological associations, who led the study with the Australian National University, said that ''teen love'' is usually infatuation - separate from that magical match felt by adults that includes sexual attraction, mutual enjoyment, social compatibility, physical affection and friendship.
Dr Pickhardt said it was far more moving and compelling for young people because they are overwhelmed by the onslaught of a deeper relationship than any other they have experienced.
A clinical psychologist at the University of Canberra, Vivienne Lewis, who specialises in treating teens, said it was not uncommon for adolescents to be referred to her practice with severe depression after a relationship of one month ends. She said infatuation, which was what most teenagers experienced in a relationship, was a more consuming emotion than love.
''They are more infatuated and consumed by the situation and that's why a break-up hurts so much: because they invest a lot in their relationship - a lot of themselves, much more than adults - so when it falls apart they are not like adults, they don't have other things to grasp on to,'' Dr Lewis said.
She said adults were better able to cope with break-ups because they were more careful.
''Teens are being overwhelmed by the endorphins and hormones that are involved and, because they aren't used to that experience, they can be completely crushed when it breaks down. Adults have usually been through a few relationships, so they are more careful,'' she said.
''For parents of adolescents, they need to understand that breaking up with someone is quite devastating because, for [teens], that is their whole life.
''Parents need to keep children engaged in lots of other things - with their family, playing sport, doing schoolwork - so the relationship is one part of their life. It's when it becomes the sole part of their life - that's when it's dangerous and when it breaks down it could lead to mental health issues.''