Depression, also known as major depressive disorder (MDD), unipolar depression, and clinical depression, is one of the most common mental disorders, affecting more than 300 million people worldwide. Depression is a serious illness that can have a substantial impact on a patient's day-to-day activities and can even be life-threatening due to suicidal tendencies. Depressed mood and anhedonia that lasts at least two weeks are the hallmarks of depression. Treatment possibilities for depression are among others antidepressant drugs and psychotherapy. Although the specific cause of depression is unknown, it is thought that in most cases, a lack of neurotransmitters such as serotonin, noradrenaline, and dopamine in the brain plays a significant part in the disease's pathogenesis. As a result, pharmacological treatments are now focused mostly on altering the amounts of these neurotransmitters in the patient. In this review I will write about the genesis, epidemiology, categorization, symptoms, diagnosis, risk factors, and therapy of depression, mainly focusing on the pharmacotherapy.