Answer: Selective Serotonin Reuptake Inhibitors (SSRI's)
Step-by-step explanation:
Serotonin is a chemical in the brain with a key role of regulating various emotions and behaviours. An imbalance of serotonin signalling in the brain is generally thought to contribute to depression.
Extracellular levels of serotonin is often noticed in people with depression, in effect to reverse this, Selective Serotonin Reuptake Inhibitors (SSRI's) are given.
This class of medications are known as antidepressants, they increase levels of extracellular serotonin by preventing its Reuptake by neurons.