Nihilistic Delusion
A nihilistic delusion is the fixed, false belief that something fundamental about oneself, or the world, does not exist. This can range from denying the existence of part of one's body or mind, to believing oneself already dead, to believing that other people, or the entire world, no longer exist or have come to a stop.
This has traditionally been described alongside delusions of enormity, in which the person believes some ordinary act of theirs could bring about a catastrophe, since both reflect a similarly extreme distortion of the person's sense of their own existence, agency, or place in the world.
Also known as
- Delusion of negation
- An alternative name for the same category, emphasising the denial of existence at its core.
- Delusion of enormity
- A related belief, sometimes occurring alongside nihilistic delusions, that the person can cause a catastrophe through some ordinary action.
Recognition features
- A fixed belief denying the existence of one's own body, mind, or self, in whole or in part
- May extend outward to a belief that other people, or the world itself, have ceased to exist or have stopped
- Sometimes accompanied by a delusion of enormity — a belief that a routine action could bring about a vast, catastrophic consequence
- Most classically occurs in the context of severe, agitated depression, though also seen in schizophrenia and delirium
Eliciting it at interview
- Ask directly, even though the content can sound implausible to voice: "Do you ever feel that you, or part of you, don't actually exist, or that you might already be dead?"
- Explore the scope of the belief carefully, since it can range from a specific body part to the entire world, and the scope itself is clinically informative
- Ask about any related belief in being able to cause catastrophic harm through an ordinary act, since this combination carries particular risk implications
Distinguishing features
- Differs from depersonalisation, in which the person feels detached or unreal but retains insight that the feeling is subjective, whereas in a nihilistic delusion the denial of existence is held as literal fact
- Differs from anosognosia, which denies a specific physical deficit rather than existence itself
- The presence of an accompanying delusion of enormity, when present, adds a distinct catastrophic quality not seen in most other delusional content
Common misconceptions
- That a person voicing this belief is speaking metaphorically or dramatically; the delusion is held as literal fact and should be explored and documented as such
- That nihilistic delusions occur only in depression; they are also recognised in schizophrenia and in states of delirium
Related phenomena
Delusion · Delusion of Guilt · Delusion of Ill Health · Delusion of Poverty · Depersonalisation
Diagnostically relevant to
Major Depressive Disorder (severe/psychotic depression) (links open the DSM-5 Learning Lab)
Practice this
A severely depressed patient states, with complete and unshakeable conviction, that his bowels have rotted away and no longer exist, holding this as literal fact despite obvious evidence to the contrary, and shows no insight that this could be a subjective feeling rather than a genuine physical absence. What is this? · Following a right parietal stroke, a patient with an obviously paralysed left arm insists nothing is wrong with it and becomes annoyed when the paralysis is pointed out, while readily acknowledging the arm itself exists and is his. Before revealing the answer: is this a nihilistic delusion? · A patient describes an abnormal experience involving part of their body. Before revealing the answer, decide what distinguishes body image disturbance from a nihilistic delusion. · Both a delusion of guilt and a nihilistic delusion are classically seen in the most severe presentations of depressive illness and often occur together. A patient says: "I don't exist anymore, I'm already dead, there's nothing left of me." Is this a delusion of guilt? · Two patients each describe, in their own way, 'not really existing.' Before revealing the answer, decide what single question best separates depersonalisation from a nihilistic delusion. · A patient describes a profound, distressing change in how their own existence feels. Before revealing the answer, decide what distinguishes disturbance of awareness of self-activity from a nihilistic delusion. · A patient makes a striking claim about his own body. Before revealing the answer, decide what distinguishes a nihilistic delusion from anosognosia. · A severely depressed patient has made an unusual claim about his own body. Before revealing the answer, decide how you would explore whether this is a nihilistic delusion. · Explain why a nihilistic delusion is most classically associated with severe, agitated depression, and why recognising it matters clinically.
Illustration
A 70-year-old man with severe, agitated depression insists that his internal organs have stopped functioning and that he is, in fact, already dead, refusing to eat on the grounds that a dead man has no need for food, and separately expresses a fixed belief that if he were to run water from a tap it would flood and destroy the entire town.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 4, 'Disorders of Thought and Speech'.