Originally Posted by Yael Grauer
Well, there ARE reasons neurotransmitters could be affected over time that have nothing to do with diet or sleep.
But I am just trying to figure out if it's those or the hormones that are most responsible. Where are all the science geeks?
I wish I was smart enough to be a science geek.
It's both. As MOD said.. everything is interconnected.. much as performance depends on input from exercise/workouts, diet and sleep so does the body's overall health from those 3 and other factors too (stress, etc.).
In any case, LIKE insulin I would speculate (having not googled this) that the reason why the pathway gets messed up is much like the downregulation of receptors. For instance, abnormally high insulin levels cause insulin receptors on cells to be removed eventually causing resistance at target tissue level or the other way which is the pancreatic B-cells just stop working b/c of too much insulin. In any case, downregulation does pretty much affect all receptors of the body.. so if too much serotonin is being produced, there would be a downregulation effect with less receptors or the axons that produce them to provide less of a response.
George's first link on SSRIs as antidepressents makes me pretty much sure of that hypothesis namely because inhibiting uptake of serotonin is basically like increased serotonin output (by allowing the serotonin to exist longer and bind to more receptors).