Unfortunately it's knowledge that I acquired orally.

I quick googling for signs of gluten insensitivity however reveals:

So you're feeling tired and headachy, and your digestive system is off (and has been for what seems like forever). Maybe you have some other symptoms: a rash, dandruff, a feeling that you're operating in a depressed and disorganized manner, or are just in a fog.

Mayo clinic writes:

Wheat sensitivity symptoms also may include headaches, rashes, "brain fog," or fatigue.

They don't use the word depression but I think a person who happens to have those symptoms scores on the Hamilton scale.