An extremely communicable disease found in hat stores catering only to the finest bro headwear and other bro paraphernalia. More severe cases include the addition of bright and oversized headphones to secure the diseased hat and transmit the illness to others. The physical manifestations of this disease lead to the patient's head tilting back and chin pointing in the air, like they just don't care.

Symptoms of this disease include but are not limited to:
-a sudden repulsion of women and female themed items
-unruly and overgrown hair on or around the neck
-attempts to "bro out" with other males (regardless of species)
-secludes self in a place referred to as a "man cave"
-loud proclamations of friendliness to women (since it conflicts with the first symptom, it creates confusion for the friends and family of the affected)

To avoid this disfiguring disease, keep an eye out for hat stores with overt bro symbols and customs (such as hats up to the ceiling and bright stickers on the bill of the hat). Also, never trade hats with someone exhibiting these symptoms due to the highly contagious nature of Bro Brain.

Cures for this affliction are being researched, however at this time no cure or vaccine is available.
"Oh dear, that poor young man seems to have caught bro brain."
"Well darn! My date started out friendly, but then I noticed the hair growths around his neck, bro customs, the frathole shirt, and knew he had Bro Brain."
by hydra-phobia July 29, 2015
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