I suffer from clinical depression. which medicine is most commonly used for clinical depression?

An SSRI: Usually, we start with one of the selective serotonin reuptake inhibitors (ssris). These include fluoxetine (prozac), sertraline (zoloft), paroxetine (paxil), citalopram (celexa), escitalopram (lexapro), and fluvoxamine (luvox). They are usually well tolerated and safe in overdose. Most of them are very inexpensive too. I would guess that fluoxetine is the most prescribed and best known.

There is not one: Medicine that works for everyone. So, there are 5 ssri's, 3 snri's, one ndri, and a host if other antidepressants. That's why it is so important for you to work closely with your doctor to find the right medicine for you!