He said many are "destabilised by falling in love, or suffer on account of their love being unrequited" and this could lead to a suicide attempt. Few studies deal with the "specific problem of lovesickness", he said.
Which sounds like a bit of a cop-out to me; I don't doubt that unrequited love has caused many mental breakdowns and suicides, though I wonder how much of that comes from the biology of the condition and how much comes from the social expectation that, when someone you fancy doesn't fancy you, you're entitled to whine, pout, go all emo and become temporarily unresponsible for your behaviour. For example, during the Victorian era, many women would faint in certain social situations. This was not due to the biology of the female gender being susceptible to sudden consciousness loss, but due to programmed-in social expectation. Could it be that losing one's shit over that one special person in the world who doesn't reciprocate one's passion is a similar case of cultural conditioning?
(Which is not to say that romantic love or sexual attraction is culturally constructed; I don't for a moment entertain the blank-slate theory of human nature. However, it's more than conceivable the expectations of how such urges are expressed, and how much they can affect one's behaviour, are strongly influenced by cultural expectations, and that, as biological and physical causes of behaviours are revealed, they gain more influence as the self-sustaining illusion of the sovereign free will becomes weakened.)
Then again, now that unrequited love is recognised as a bona fide medical condition, perhaps some pharmaceutical company will seize the opportunity and bring out an anti-unrequited-love drug, a sort of Prozac for the heart which quickly and conveniently cures this debilitating ailment, further streamlining the human condition.