英语时差:社会现象
In the United States someone attempts suicide every minute. In a single day roughly eighty Americans kill themselves. What compels so many people to end their lives prematurely? Countless elements factor into the fatal decision that leads to suicide. In recent years, however, scientists have been searching for an underlying biological explanation. Although not conclusive, the most compelling evidence points to irregularities in a brain chemical called serotonin.
Serotonin is a neurotransmitter, meaning that it travels between neurons in the brain to relay chemical messages. When neurons communicate they release serotonin into the space between neurons called the synapse. After the serotonin has delivered its message, the neuron sending the serotonin reabsorbs the chemical. Besides working as a chemical messenger, serotonin seems to sooth the mind. Antidepressant drugs such as Prozac work by causing serotonin to remain in the synapses longer before being reabsorbed, thus having an even greater calming effect.
Several studies have linked suicide to low levels of serotonin in the brain. Scientists have determined that the brains of at least some suicide victims had tried to horde serotonin by not allowing it to be reabsorbed into the synapse. While low serotonin levels alone do not cause someone to commit suicide, they seem to play an important role.
Although lithium in pill form is a proven suicide deterrent, many at-risk patients shun the drug due to side effects including hand tremors, thirst, and weight gain.
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