"Why? The Neuroscience of Suicide -
New research addresses the wrenching question left when someone ends
his or her own life"

By Carol Ezzell

http://www.sciam.com/article.cfm?colID=1&a...B3B809EC588EEDF

"... One focus is on differences in the availability of the
brain chemical serotonin--previous research on the basis
of impulsivity has indicated a dearth of it.

"Serotonin is a neurotransmitter, one of the molecules that
jumps the tiny gaps known as synapses between neurons to relay
a signal from one such brain cell to another. Tiny membranous
bubbles called vesicles erupt from each signal-sending, or
presynaptic, neuron, releasing serotonin into the synapse.
Receptors on the receiving, or postsynaptic, neurons bind to
the neurotransmitter and register biochemical changes in the
cell that can change its ability to respond to other stimuli or
to turn genes on or off. After a short while, the presynaptic
cells reabsorb the serotonin using molecular sponges termed
serotonin transporters.

"Serotonin somehow exerts a calming influence on the mind.
Prozac and similar antidepressant drugs work by binding to
serotonin transporters and preventing presynaptic neurons from
soaking up the secreted serotonin too quickly, allowing it to
linger a bit longer in the synapse and continue to transmit its
soothing effect.

"More than two decades of reports have linked low serotonin
levels in the brain to depression, aggressive behavior and a
tendency toward impulsiveness, but the evidence has been
particularly confusing with regard to suicide. A number of
studies have found reductions in serotonin in the brains of
suicides, whereas others have not. Some have observed a lack of
serotonin in one part of the brain but not elsewhere. Still
others have described increases in the number of receptors for
serotonin or deficits in the chain of chemical events that
convey the serotonin signal from those receptors to the inside
of a neuron.

"Despite the inconsistencies, the bulk of evidence points
strongly to a problem in the brains of suicides involving
the serotonin system."
[Cont... ]
http://www.sciam.com/article.cfm?colID=1&a...B3B809EC588EEDF

Suicide is the 11th leading cause of death in the U.S.,
accounting for 1.2 percent of all fatalities.

A person dies by suicide roughly every 18 minutes in
the U.S. Someone attempts suicide every minute.

Four males die by suicide for every female, but at least
twice as many women as men attempt suicide.

Approximately 80 Americans take their own lives every day.

The suicide rate for white males aged 15 to 24 has
tripled since 1950.

Between 1980 and 1996 the suicide rate for African-American
males aged 15 to 19 increased 105 percent.

Suicide is the third-ranking cause of death for teens
aged 10 to 19.

White men 85 and older die by suicide at six times the
overall national rate.

Suicide rates for women peak between the ages of 45 and 54
and surge again after age 85.

Alcoholism is a factor in roughly 30 percent of all
completed suicides.

Approximately 7 percent of people with alcohol dependence
will die by suicide.

Eighty-three percent of gun-related deaths in the home
are the result of suicide.

Death by firearms is the fastest-growing method of suicide.

Suicides outnumber homicides two to one every year in the U.S.

Suicide accounts for nearly 57 percent of all firearm deaths
in the U.S.; 60 percent of all suicides involve firearms.