I'd heard that Goya's work got very dark in his latter years. This information clearly demonstrates what the derogatory effects that heavy metal poisoning (in Goya's case, lead) can have not only on the physiology but the mind as well.
Now, consider how the poisoning of SEVERAL heavy metals could wreak on the body/mind and then add halogen imbalance syndrome to the mix! S-Y-N-E-R-G-Y.