With the advent of monoamine oxidase inhibitors (MAOIs) and
tricyclic antidepressants (TCAs) in the 1950s, depression
treatment was revolutionized. These medicines target the
monoamine system, including the neurotransmitters serotonin,
norepinephrine and dopamine. For decades, the dominant
hypothesis of depression has been that low levels of monoamines
in the brain cause this debilitating disorder. In the ‘80s, the
selective serotonin reuptake inhibitor (SSRI) fluoxetine (brand
name: Prozac) heralded a new era of safer drugs which also
target the monoamine system. Since then, various SSRIs and
serotonin-norepinephrine reuptake inhibitors (or SNRIs) have
been developed as new antidepressants. While these drugs aren’t
more effective than older antidepressants, they are less toxic.
But SSRIs and SNRIs don’t work for everyone, so MAOIs and TCAs
still are prescribed. Two out of three patients with depression
do not fully recover on an antidepressant medication according
to findings from STAR*D, the largest clinica