Van Gogh & Ergot

[dip]

Look close at these paintings, upon the wheat: looks like ergot? I strongly believe this artist, aswell as countless other artists, philosophers, and architects indulged in this psychoactive substance - by accident. Does anyone else think so? It would account for his bizzare behavior and hallucinations. Also consider his mental and emotional instability, ending in a suicide.
erowid:

Individuals currently in the midst of emotional or psychological upheaval in their everyday lives should be careful about choosing to use strong psychedelics as they can trigger even more difficulty.

I can't really find any hard evidence or research articles involving Vincent Van Gogh and Ergot, however. His mental condition was also probably linked to Absinthe and lead poisoning.
Are there any books or research articles that include Van Gogh consuming Ergot?