psycho-biochemical test, which was developed by Dr. Eric Braverman on the basis of his own psycho-biochemical theory, according to which one of the four neurotransmitters (dopamine, GABA, acetylcholine, serotonin) is dominant and determines a person’s temperament and behavior. The test, published in the book “The Edge Effect” (2005), is designed to determine your neurochemical type, as well as detect signs of neurotransmitter deficiency.