I have a friend suffering from depression. He takes anti-depressants to help.
People woth depression may be notably sad, anxious, or empty; they may also feel notably hopeless, helpless, dejected, or worthless.
Yeah I feel sorry for them. It must be tough to feel those emotions.
It is a very difficult thing that can affect a person's thoughts, behavior, feelings, and sense of well-being.
I am glad that there are drugs that also help such as Prozac and Paxil.
Sometimes depression is a normal temporary reaction to life events and drugs are not needed. 
That is true. Sometimes psychotherapy is all that is needed for patients to start feeling better.
Psychotherapy is aimed to improve an individual's well-being and mental health
Yeah I believe Sigmund Freud started the practice. It has helped so many people!
Sigmund Freud
Sigmund Freud ( ; ; born Sigismund Schlomo Freud; 6 May 1856 – 23 September 1939) was an Austrian neurologist and the founder of psychoanalysis, a clinical method for treating psychopathology through dialogue between a patient and a psychoanalyst.
Freud was born to Galician Jewish parents in the Moravian town of Freiberg, in the Austrian Empire. He qualified as a doctor of medicine in 1881 at the University of Vienna. Upon completing his habilitation in 1885, he was appointed a docent in neuropathology and became an affiliated professor
. Depressed people may also feel sad, anxious, empty, hopeless, worried, helpless, worthless, guilty, irritable, hurt, or restless. They may lose interest in activities that once were pleasurable, experience loss of appetite or overeating, have problems concentrating, remembering details, or making decisions, and may contemplate or attempt suicide. Insomnia, excessive sleeping, fatigue, loss of energy, or aches, pains, or digestive problems that are resistant to treatment may also be present.
About one in six people