How Psychotropic Drugs Work

To understand how these mind-affecting drugs work, it is necessary to understand
a little of how the brain works. The brain is made up primarily of
neurons (nerve cells) that form circuits controlling thoughts, emotions,
physical activities, and basic life functions. These nerve cells do not actually
touch one another but are separated by gaps called synapses. An electrical
impulse moves along the neuron. When it reaches the end, it stimulates the
release of chemicals called neurotransmitters into the synapse. These chemicals
then fit into receptors on the next neuron and affect its electrical impulse.
The neurotransmitters act by either causing the release of the electric
impulse or inhibiting it so the neuron does not fire. Any neurotransmitter
left in the synapse is then reabsorbed into the original neuron. This process
is called reuptake.

Problems can arise from either too much or too little neurotransmission.
Too much transmission may occur when the neuron fires in the absence of a
stimulus or when too many neurotransmitters attach to the receptors on the
far side of the synapse (the postsynaptic receptors). Too little transmission
can occur when too few neurotransmitters attach to these postsynaptic receptors.
The primary neurotransmitters involved in mental illnesses and
their treatment are dopamine, serotonin (5-HT), norepinephrine, and
gamma-aminobutyric acid (GABA). 301