Prozac is a widely prescribed antidepressant that has been used since the 1980s. It works by increasing serotonin levels in the brain, which can produce feelings of well-being. Studies show it may also promote neuron growth. Prozac is used to treat depression, OCD, bulimia, panic disorders, and PMS. It takes 3-4 weeks to see improvement in mood and symptoms. Long term use for 6-12 months is typically recommended for sustained benefits. Prozac should be used cautiously in children and those with liver or kidney disease.