Doctors, what are the chemicals in synthetic weed and is gallbladder problems one of the effects from smoking?

Hard to say: There are literally hundreds of synthetic cannabinoids, which can be very different chemicals with different effects. There are about 5 common chemicals found in spice/k2, but the concentrations are uneven and some batches may be toxic while others have very little drug. It may be contaminated with other chemicals as well. There are reports of gallbladder problems with these drugs. Stop using them.