Sometime ago I'd heard someone trained in child psychology claim that crying for emotional reasons (as opposed to getting something in your eye for example) released toxins from the brain and/or body. More specifically, she claimed that emotionally-based tears, when collected and fed to rats in their food, resulted in a markedly increased statistical rate of disease and mortality in comparison to reflex-based tears or no tears at all. The explanation seemed a little hand-wavy, was uncited, and I was a little bit suspicious.
However, I have noticed for some time that emotionally-based tears taste different depending on the "bitterness" of the experience. Then, I recently went through an extremely stressful time where I experienced levels of emotional stress higher than I ever have in my life. I found to my surprise that my tears during this period, if allowed to drain down my throat, caused extreme soreness for a short period of time (mitigated by drinking liquids); whereas if I was careful not to allow them to, no soreness resulted. A friend also experiencing extreme emotional stress found that the specific areas on her cheeks that her tears touched became visibly red and raw. Again, her experience was that the rawness correlated with contact vs no contact in specific incidents--rather than frequency. These responses seemed too specific to be psychosomatic.
Now, "toxins" is very vague and it's clear that crying is an important emotional tool regardless of whether its significance is psychologically- or physiologically-based. My sample-space is unsatisfactorily small, but has intrigued me. Is there any scientific evidence that:
- Emotionally-driven tears contain substances harmful to the body, and if so which substances and by which mechanisms.
- Emotionally-driven tears contain substances which are in some way specifically related to stress.
- And, if either of the above are true, is it scientifically plausible that the substances in emotionally-driven tears are in any way originating in the brain?
I'm especially interested any evidence which suggests there is a good reason to fully expel emotionally-driven tears from the body, and any that suggests failure to cry under emotional stress prevents the release of a substance which ought to be released for body/brain health. Does anyone have any good research on these topics? My apologies for the length and detail of the question.
Edit: I've also recently experienced stinging cheeks after an especially poignant (yet low tear volume) cry. Since this is now a topic of curiousity for me it's hard to rule out a psychosomatic effect, but it was a distinct enough feeling to bump this post with an edit. No hard sources out there, anyone?