What causes gallbladder hypercontractility?

Gallbladder. It's the way your own gb may contract but often stimulated by a meal particularly one high in fat.
Stimulation. The gallbladder secretes in response to a stimulation of food in the stomach. The stomach sends a signal that bile salts need to be in the intestines to help absorb. The test to see function of the gallbladder use cholecystokinin to stimulate the gall bladder to contract and send the bile into the intestine. Many things could mimic this.