The Authors, Siever & Frucht, found some new jargon to mediate the old battle between genetic and environmental factors in mental illness. All they managed to say is that genes don't exist in a vacuum. But they did manage a couple of good metaphors to show How Genes and Neurotransmitters Shape Your Mind. Their book reads like a textbook and is not for the lay reader.
One metaphor they used was the thermostat. Brain states are determined by whether neurons fire or don't fire. In other words, whether signals pass through the walls of the neuron's membrane. Neurons in various sections of the brain function as a thermostat to set their sensitivity to neurotransmitters such as serotonin, dopamine and acetylcholine. The receptors for these neurotransmitters are embedded in the neuron's membranes. Thus, states of mind depend upon the ion flow of chloride, calcium and sodium through these receptors embedded in the membranes. The unseen hand setting the thermostat could be either brain made proteins or ingested drugs, all of which can either excite or inhibit neuron firing. To demonstrate how opaque this field is, the Authors included quantum physics in their discussion. Probabilities, depending on the 3-D heat fluctuations of proteins, can determine whether a protein fits a receptor and whether firing occurs.
The Authors made Herculean attempts to connect the flow of neurotransmitters to one's personality. But factors like one's impulsivity are far more abstract and not quite like high cholesterol as the Authors suggest. In other words the Authors were stretching their metaphors in a rather desperate attempt to put a new face on mental illness. Evidently we are still miles away from any concrete understanding of mental illness.