Psilocybin inhibits the processing of negative emotions in the brain

This one is way out there. I'm sure your doctor would never think of prescribing 'magic mushrooms' to combat your depressive state because your doctor did nothing to stop the neuronal cascade of death. Hell, we can't even get marijuana off the Schedule I drug list and that has tons of proven research.
http://www.sciencedaily.com/releases/2014/05/140507095756.htm
Researchers at the Psychiatric University Hospital of Zurich have now shown that psilocybin, the bioactive component in the Mexican magic mushroom, influences the amygdala, thereby weakening the processing of negative stimuli. These findings could "point the way to novel approaches to treatment" comments the lead author Rainer Krähenmann on the results which have now been published in the medical journal Biological Psychiatry.
Psilocybin inhibits the processing of negative emotions in the amygdala
The processing of emotions can be impaired by various causes and elicit mental disorders. Elevated activity of the amygdala in response to stimuli leads to the neurons strengthening negative signals and weakening the processing of positive ones. This mechanism plays an important role in the development of depression and anxiety disorders. Psilocybin intervenes specifically in this mechanism as shown by Dr. Rainer Krähenmann's research team of the Neuropsychopharmacology and Brain Imaging Unit led by Prof. Dr. Franz Vollenweider.

More at link.