Serotonin deficiency?

I read a post I think from longterm about EC and a serotonin deficiency - but I cant find it now - can someone repost that? That stuck in my mind because some people have been helped by taking anti=depressants - maybe not because it is 'all in your head" but maybe EC is caused by low serotonin. Low serotonin can cause physical symptoms. And - a lot of people that have this do seem to be somewhat anxious/depressed? There are some natural serotonin things you can take like 5- htp - has anyone tried these or anti-depressants? I know one person said anti=depressants did not help - I think it was alesiom. but may be worth a try.