I was taking this daily last winter (to combat my allergies at work to drug dust)
daily. And I had that major depressive problem then!

I haven't needed it since I quit working, and "retired".

I've been using it since it came out... in spurts. Last year was the most I used it every day in a row. (months).

I typically use it seasonally. It has been great for my minor asthma attacks.

I think the mechanism is that it prevents histamine release. Histamine is a neurotransmitter in the brain, and as such is a signaling neurotransmitter, that stimulates the release of other neurotransmitters.

I'll be interested in what materializes with this information. It is similar in scope to the Vioxx debacle. Vioxx was a potent Cox-2 inhibitor, and as such prevented GOOD Cox-2 prostacyclin from doing its job, dilating arteries.

It seems that tinkering with these sensitive systems is not really safe in the long run. In the short run, no harm. But years and years? That is when things show up.