When people talk about depression sometimes they refer to different types based upon what they think may have caused their depression. One such possible cause is existential in nature, that is, a person ends up questioning his or her life, death or meaning of life, and by doing so, lapses into depression.
According to existentialism, a specific type of philosophy, humans are driven to meaning in their lives not by a specific type of deity or god, or by an outside authority, but internally, through our own choices, desires and pursuits. Humans are entirely free, and, therefore, entirely responsible for their own happiness or misery. It is up to each one of us to create the meaning which drives our life, whether it be through work, hobbies, charity, religion, relationships, offspring, family, or something else.
Existential depression may occur when a person comes face to face with these kinds of issues of life,
death, freedom and the meaning of their life. For instance, a person with existential depression might ask themselves, "What is the meaning of my life? Is it only to work 9 to 5, have a family, and then die? Will I ever find someone who truly understands and believes in me no matter what? Does god care about me? Does anyone else truly care about me?" Existential depression may be characterized by a unique sense of hopelessness in feeling that our lives may actually be meaningless.
People who experience normal clinical depression may also experience existential issues related to the meaning of their life in the course of
psychotherapy to treat the depression. This is a normal component of treatment of depression, and many clinicians will often work with the person to help them explore the meaning of their life if this happens.
Finding one's meaning or passion in life is something that many people consider important, and an episode of existential depression can help focus a person's need to find an answer to that question. Existential depression is usually treated not with any type of prescription medication, but rather psychotherapy focused on helping the person explore the meaning of their life.
Existential depression may be caused by a specific event in the person's life (e.g., loss of a job or a loved one), or nothing at all. Existential depression has not been widely researched and no specific therapeutic approaches have been shown to work better than others in its treatment.
There isn't a specific DSM V diagnosis for it. It is known, but not widely agreed upon.
Like Chronic Fatigue Syndrome. Some recognize it, some do not.