Re: Why do people fall in love?

Your question specifically is on which chemicals are released when people 
fall in love and I will address that issue instead of the more general 
question of "why do people fall in love" which is much more complicated and 
can not be reduced to neurotransmitter activity. Work by 
psychiatrists Michael Liebowitz and Donal Klein has led them to speculate 
that the release of the small molecule phenylethylamine (PEA)in certain 
regions of the brain is involved in emotional responses which lead to 
feelings of  elation and attraction to a mate. This chemical causes a 
natural high since PEA is an endogenous form of "speed". 
This natural "high" it has been argued, is what lovers feel when they 
are infatuated with one another. This work is discussed in the book "The 
anatomy of love" by Anthropologist Helen 
Fisher.

hope this helps,
gabriel vargas md/phd