First of all, many anabolics cause hunger. Not just eq. Dbol quite famous, test at many doses, and tren can make many very hungry. All are presumed to affect histaminic and glucocorticoid receptors. As far as anxiety, winny definitely, and eq often has been shown to strip GABA receptors in the brain as well as affect serotonin receptor density. Benzodiapenes (which agonize GABA) and antidepressants (which raise serotonin) are both used for anxiety treatment. So the fact that many steroids affect GABA and serotonin in individuals to different degrees has been enough to explain the occasional reaction.
In other words, there is no mystery here. And there is nothing unique about eq. Often this board seems not to understand that all AR anabolics are fairly similar in basic mechanisms, and non-ar anabolics are fairly similar in their way. It's not like eq is some unbelievable molecule. It might as well be an injectable dbol, if you consider its shape. There is not some holy grail of knowledge at the end of your questions. This has been overdone some time ago. Let the horse die, and focus on growth.
The only scientific uncertainties in AAS are how stacking affects results. Each anabolic's receptor profile has been uncovered enough to explain its common sides. This was done by the 70's for most agents. Research now focuses on how hitting the anabolic receptor (by any aas) actually causes growth, through which messengers, etc. Also, the utility of GH, especially when combined with anabolics, is still quite uncertain.