dump enough of the right kind of transmitter substance to bind with
enough specific receptors in the other cell to cause it to change polarity.
To make matters even more complex, the receptors, in addition to being
specific, must be open and in a sensitive state.
Different areas of the brain are composed of cells with relatively
more receptors that bind with specific transmitter substances. These brain
areas are connected to other areas via transmission pathways called by the
name of the substance, as in serotonin pathways.To make matters still
more complicated, each transmitter substance can serve as messenger in
many different kinds of pathways that have different functions and dif-
ferent binding sites in different brain centers. If you increase the amount
of one transmitter substance relative to others, there will be effects in vir-
tually every area of the brain. Serotonin pathways are involved in sex,
sleep, mood, memory, motivation, emotion, and just about everything
else, so increasing available serotonin has effects nearly everywhere,
though the effects may vary tremendously among individuals.
You do not need to know all this, but you do need to understand that
chemical transmission in the brain is an enormously complicated process
that occurs on a molecular level that cannot as yet be directly observed,
and that everything connects to everything else in a number of ways, none
of which are completely understood.
Psychiatric Drugs
All psychiatric medications operate by manipulating chemical transmission.
They work by increasing or decreasing the amount of transmitter substance
available, or by blocking or unblocking receptors. Some act on receptor
sites like transmitter substances themselves, but most do not because of
the blood-brain barrier. Though only a few molecules of serotonin are
needed for transmission, you could eat a pound of it with little effect
because it can’t get through to your brain. Psychiatric medications are
substances that get through the barrier and, once on the other side, affect
the production and metabolism of various neurochemicals. They do many
other things as well, but we’re not sure what they are.
Virtually all psychiatric medicines in use today began as drugs for
other purposes. They were found to have an effect on mental illnesses
while being used to treat something else. The basic classes of drugs were
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