An existential crisis is a moment at which an individual questions the very foundations of their life: whether this life has any meaning, purpose, or value. This issue of the meaning and purpose of existence is the topic of the philosophical school of existentialism.
An existential crisis may result from, be a misdiagnosis of, or be comorbid with:
An existential crisis is often provoked by a significant event in the person's life—psychological trauma, marriage, separation, major loss, the death of a loved one, a life-threatening experience, a new love partner, psychoactive drug use, adult children leaving home, reaching a personally significant age (turning 16, turning 40, etc.), etc. Usually, it provokes the sufferer's introspection about personal mortality, thus revealing the psychological repression of said awareness.
An existential crisis may resemble anomie (a personal condition resulting from a lack of norms) or a midlife crisis. An existential crisis may stem from one's new perception of life and existence. Analogously, existentialism posits that a person can and does define the meaning and purpose of his or her life, and therefore must choose to resolve the crisis of existence.
In existentialist philosophy, the term 'existential crisis' specifically relates to the crisis of the individual when they realize that they must always define their own lives through the choices they make. The existential crisis occurs when one recognizes that even the decision to either refrain from action or withhold assent to a particular choice is, in itself, a choice. In other words, humankind is "condemned" to freedom. It can also be noted that once one is out of an existential crisis, they are easily able to get into another, or aren't completely out of it.
Existential crisis is considered by many to be a direct consequence of depression.
Peter Wessel Zapffe, a Norwegian philosopher and adherent of nihilism and antinatalism, asserted in his book, The Last Messiah, four ways that he believed all self-conscious beings use in order to cope with their apprehension of indifference and absurdity in existence, comprising "anchoring", "isolation", "distraction", and "sublimation":