CHEMISTRY OF THE BRAIN: MOLECULES, MOOD, AND MENTAL ILLNESS - Chemistry: Notable Research and Discoveries - page 101

19 Swedish chemist Arvid Carlsson discovers that do-

pamine is a neurotransmitter.

19 Dutch researcher Jacques van Rossum proposes the

dopamine hypothesis of schizophrenia, which attri-
butes the symptoms of the disease to an excess of
dopamine.

190s Selective serotonin reuptake inhibitors (SSRIs) such

as fluoxetine (Prozac) begin to be used as antide-
pressants. These medications are generally effective
and have fewer side effects than earlier drugs.

Researchers begin to examine dopamine's role in
the brain's reward system and in the reinforcing
aspects of drugs of abuse.

1990s Although acknowledging the relevance of mono-

amine neurotransmitters in depression, research-
ers begin to examine other mechanisms such as
neurogenesis that may also play an important role
in the development of the disease.

Improved methods of studying brain chemicals, in-
cluding methods such as PET that permit the study
of living tissue, confirm the importance of dopa-
mine in schizophrenia, though it is probably not the
only factor. Scientists study other factors, many of
which are related to synaptic transmission, such as
genes involved in synaptic transmission.

00 Luca Santarelli, René Hen, and their colleagues use

a mouse model of depression and find evidence of
a role of neurogenesis in antidepressant activity.

00 Jeffrey W. Dalley and his colleagues use animal

models and imaging to show that the physiologi-
cal state of dopamine neurotransmission may be
an important factor in substance abuse problems.