Antidepressant

An antidepressant is a type of medication that is used to treat people with mood disorders including depression and also to treat people with anxiety disorders. Some people take antidepressants to lower their sex drive and treat premature ejaculation.
There are different types of antidepressant, such as monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), tetracyclic antidepressants (TeCAs), selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs). 
How they work.
Antidepressants work to improve the mood. Doctors think that when someone is depressed, the chemicals in their brain are not working properly. Antidepressants balance these chemicals, lifting the depression.