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Bizarre Delusions

Nerdyssey December 13, 2025


1) Overview — What Are Bizarre Delusions?

Bizarre delusions are false, delusional beliefs that are clearly impossible in the real world, or that straightforwardly violate the laws of nature / physics / biology. They are not just “unlikely” at the level of feeling, but are at a level where—even if you bring in logic, science, or normal life experience to explain them—there is still “no way this could ever happen.” Importantly, most people in the same culture, upon hearing them, will feel more like “How could that even happen?” than “Well… maybe it’s possible?”

When we talk about bizarre delusions, we are talking about “how strange the content of a delusion is”, not talking about “a separate diagnosis.” Bizarre delusions are not a standalone diagnosis; they are a content attribute that can appear in many disorders that involve psychosis, such as Schizophrenia, Schizoaffective Disorder, Delusional Disorder, Mood Disorder with Psychotic Features, or even Psychosis due to substances / certain medical conditions. Clinically, it functions more like a “content label” than a distinct disease entity.

The core point is that bizarre delusions must still be “delusions” first. That means they are:

  • Beliefs that significantly deviate from reality
  • Held with strong conviction, even when there is contradicting evidence
  • Not easily corrected by reasoning or new information
  • Not beliefs that are “shared” within the person’s religion / culture / sect / community

Then, the word “bizarre” adds the extra condition that the content of the belief breaks basic physical reality directly, such as: internal organs being removed and rearranged without any wound, thoughts being sucked out using an invisible machine, the entire world being switched into a fake version yesterday where everyone except oneself has been replaced by human-looking robots, etc.

A common source of confusion is people using the word “bizarre = weird” in everyday language as a blanket term, whereas in psychiatry, “weird/odd/extreme” is not enough to be called a bizarre delusion if, in theory, it is still “technically possible.” For example, the belief that “I am being followed by a secret organization” or “all of my phones are being hacked” may sound over the top, but if you strip it down to its scientific core, it still belongs in the category of things that could actually happen in this world. Therefore, by the classic definition, it is placed on the non-bizarre side.

Another important point is: Bizarre delusions ≠ insulting or invalidating religious / spiritual beliefs. If a belief lies outside scientific explanation but is accepted by people in that society or religious community—such as beliefs in heaven and hell, spirits, merit-making and karmic return—then according to DSM/ICD principles, it is not considered a delusion, because it is a “shared belief” embedded in a cultural framework. Labeling something a delusion must always be done with care for social, cultural, and religious context, not purely through a scientific lens alone.

In practice, “bizarre delusions” are often discussed in the context of psychotic disorders, especially those in the Schizophrenia spectrum, because they reflect that the reality-testing system and the system that processes experiences about “self and world” (self & world model) are significantly damaged. The brain becomes able to accept explanations that contradict basic reality in a coherent, story-like way. Patients are often not just “misunderstanding a few things,” but rather it is as if “the entire manual for how the world works inside their head” has been rewritten.

Examples of contents commonly categorized as bizarre (listed to illustrate, not to romanticize or use as entertainment ideas):

  • Believing that all internal organs have been replaced with someone else’s organs last night, but there are no wounds and no physical evidence of any procedure
  • Believing that one’s own thoughts are being sucked out of the brain by energy waves/invisible devices hidden in the walls or coming from another planet
  • Believing that the entire world is a fake version that was switched yesterday, and everyone around has been replaced with look-alike replicas, with no one being “the real person” anymore
  • Believing that one’s own body has truly disappeared, with no internal organs remaining, or that one is no longer a living being at all (some of this overlaps with nihilistic / Cotard-like themes)

What should be emphasized in the Overview is that bizarre delusions are not just random whimsical fantasies. People with these symptoms are not “making things up for fun” or “craving attention.” They are living in a “version of reality” that their brain believes to be absolutely real. The fear, despair, suspiciousness, or panic that follows are therefore “real feelings” in that world, not just emotional drama.

Another aspect that often goes unmentioned is that bizarre delusions do not mean the person is “stupid” or “irrational” by default. Many cases involve individuals who previously had good intellect, education, and logic in other areas of life. But once the chemistry and neural networks involved in interpreting reality become distorted, their reasoning ability gets used to “protect the false belief” rather than to challenge it. The more they try to explain, the more elaborate, complex, and out-of-this-world the explanation can sound.

Finally, in modern diagnostic systems, DSM-5-TR treats the word “bizarre” as a descriptive specifier / content descriptor rather than as a sharp dividing criterion like in older editions (which used to give bizarre delusions special weight in diagnosing schizophrenia and excluded them from delusional disorder). Therefore, when explaining the Overview for readers, it is best to summarize it like this:

  • Bizarre delusions = “Delusions whose content is clearly impossible in the real world.”
  • They are an indicator of how far the internal world has detached from shared reality, not a standalone disease name.
  • And they are not a word meant to mock or make someone’s suffering into a joke.

2) Core Symptoms — Core Features of Bizarre Delusions

A simple starting point is:

Bizarre delusions = “full-blown delusions” + content that is so out of this world it cannot exist under natural laws.

So, when writing or explaining, don’t jump straight to the word “bizarre.” Start by asking:

“Is this truly a delusion?”
Then ask: “Does the content qualify as bizarre?”

2.1 The Properties of “Delusion” (Clinical Structure)

There are three main pillars to always consider:

  1. High conviction
  2. Resistance to change / not corrected by evidence
  3. Not a culturally shared belief

2.1.1 Firm Conviction (High Conviction)

The person believes 100% or close to 100% that what they think is true. It is not just a “Hmm… maybe?” thought.

  • There is no mode of “just thinking out loud” / “maybe” like in typical people. Instead, it’s in the mode of “this is definitely true.”
  • Delusional beliefs usually sit at a level like:
    • If 10 = belief like “The house is on fire right now.”
    • A delusion is commonly at level 8–10 most of the time.

Different from what?

  • Different from normal doubt/suspiciousness, such as:
    “I feel like my partner has changed. Are they talking to someone else?” → The person is still open to listening to evidence, still able to reconsider, still able to leave room for being wrong.
  • Different from a hypothesis or “playing with an idea,” such as:
    “Maybe the government listens in on us sometimes.” But the speaker themselves laughs it off and knows they’re exaggerating.

When you put this into writing, emphasize:

A delusion is not just “a strange thought.”
It is a belief the person has, in effect, signed and sealed in their mind as true.

2.1.2 Not Easily Corrected by Reason (Incorrigibility)

This is the part where “even when the evidence smacks them in the face,” the belief remains.

For example:

  • Someone believes they have a chip implanted in their body → They go for MRI, X-ray, CT scans and everything is normal.
    But they may say:

“The hospital equipment is controlled / they hid the chip in a way normal machines can’t detect.”

  • Or someone believes “my partner is definitely cheating on me,” even when there is extremely clear evidence to the contrary, yet their belief doesn’t loosen.

Key point for writing:

  • It’s not just “bad reasoning.”
  • It is that “the reasoning system is being used to protect the belief” rather than to test it.

→ You see patterns like:

  • Supporting evidence: used to reinforce the belief
  • Contradictory evidence: re-interpreted in a way that fits the delusion

2.1.3 Not a Culturally/Religiously Shared Belief

This is a very important item when writing in a way that is careful and non-disparaging.

If a belief is:

  • Part of a religious belief / ritual practice / local cultural belief, and
  • A significant number of people in the same community also hold or understand that concept

→ Then, by the principles of DSM/ICD, it is not classified as a delusion.

For example:

  • Belief in “spirits/ghosts” under the framework of a religion or local belief system → is not automatically a delusion.
  • But if one specific person believes that “this particular ghost forces my right arm to move every time someone looks at me”, in a way that doesn’t fit the religious/cultural framework → this starts to lean toward delusion (and then we further decide whether it is bizarre or not).

In your article, you should pull this point into a small box such as:

“What’s the difference between religious belief vs delusion?”

It will make the content look both respectful to readers and scientifically grounded.

2.2 The Properties of “Bizarre” (The Strangeness of the Content)

Now that we have the structural framework of a delusion, the next step is to ask:

Does the content break the normal rules of physics/biology/logic?

2.2.1 Clearly Impossible (Physically / Biologically Impossible)

A bizarre delusion is content that:

  • Is not just “unlikely,”
  • But is at the level of “this cannot happen as long as the world still runs on these physical laws.”

Some conceptual examples (do not romanticize in fiction without clear warning):

  • Believing someone took the brain out, washed it, and put it back in without any wound or scar
  • Believing someone instantly swapped all the blood in their body with someone else’s in a split second
  • Believing one’s own thoughts are being pulled out of the head by a multidimensional machine without anything touching the body

These “ram straight into the wall of physics.”

Compare with non-bizarre:

  • Believing that one is being followed all the time →
    In the real world, this could be possible (cameras, investigators, an actual stalker).
  • Believing the government is listening in on phone calls → falls into a category of “more or less likely,” but still not impossible.

When explaining this in an article, use a structure like:

  • Non-bizarre delusion = false belief that is “technically possible” in the real world.
  • Bizarre delusion = false belief that “hits the wall of physics/biology head-on.”

2.2.2 Not Explainable by Normal Psychology

Another side of “bizarre” is that:

It is not just an extension of life experience + normal psychological processes.

For example:

  • A person who has been betrayed in the past → becomes very suspicious of the next partner → this can still be explained by “past experience + trauma.”
  • But if someone with no such history says:

“Everyone in the country became robots whose souls were removed yesterday; I am the last real human.”

Then this is no longer just “suspicion extended from the past.” It is that the structure of how the entire world is perceived has been rewritten.

Nice summary for writing:

  • A “regular” delusion = a false belief that can still be linked to “real experiences + basic human fears.”
  • A bizarre delusion = a false belief that is cut off from the normal constitution of the world and cannot be adequately explained by life experience alone.

2.3 Commonly Co-Occurring Features (Associated Features)

These are “supporting actors” that often appear together. They are not strict criteria, but they commonly show up when describing/observing cases.

2.3.1 Low Insight (Not Recognizing It as a Symptom)

The person truly believes what they experience is 100% real, and:

  • Does not think it is an illness
  • Does not think it is the brain playing tricks on them

If someone says, “This might be a psychiatric symptom, you know,” then in most cases they feel:

  • Threatened
  • Insulted
  • As if their reality is being denied

You can explain this to readers in simple terms as:

Low insight = “The brain is shouting ‘this is reality’ so loudly that every other voice goes silent.”

2.3.2 High Distress, Fear, and Hypervigilance

Many cases of bizarre delusions come with a very strong emotional tone, such as:

  • Panic-level fear
  • Extreme despair (especially when overlapping with nihilistic content)

Even if the content appears “fantastical,” the emotion inside is not fantastical at all. It is genuine crisis-level stress.

This is especially important for writing in a “stigma-reducing” way:

  • Emphasize that people with delusions are not “trying to think weird things” or “seeking attention.”
  • They are living in that version of the world for real, along with very real fear.

2.3.3 Behavior That Matches the Belief

This is a major signature of delusions, both bizarre and non-bizarre:

  • If someone believes that their thoughts are being controlled → they might cover their ears, wear a helmet, wrap their head, to block “signals.”
  • If they believe their body has been changed → they might repeatedly seek medical tests, take photos of themselves to check constantly.
  • If they believe the world is not real → they might perform unusual “tests” to prove that the “simulation” has a bug.

When you write, include small narrative examples to help readers feel it:

“If you truly believed that someone was intercepting your thoughts every single second,
wearing a hat/headphones/hood wouldn’t be weird at all—it would be how you survive in that version of the world.”

3) Diagnostic Criteria — How to Use Them Without Misdiagnosing

This is the section where “most people misunderstand,” and it’s a golden opportunity for you to make your content stand out from other sites.

Big picture:

  • Bizarre delusion = a property of content
  • Not a disease name, not a diagnosis, not the rule “if it’s present = must be schizophrenia.”

Think of “bizarre” as a tag / specifier / label, not as “the disease” itself.

3.1 In DSM — From DSM-IV to DSM-5 / DSM-5-TR

3.1.1 DSM-IV (Older Era): Bizarre Got a Bit of “Privilege”

In DSM-IV:

  • Schizophrenia Criterion A gave “special weight” to bizarre delusions. For example:
    • If bizarre delusions are present → that is a strong piece of evidence in favor of schizophrenia.
  • Delusional Disorder, on the other hand, emphasized that delusions had to be non-bizarre (i.e., the content had to be potentially possible in real life).

The side effect was:

  • Some clinicians internalized a mental shortcut: “bizarre delusion = schizophrenia.”
  • Many people formed a fixed image that:

“Bizarre = schizophrenia, non-bizarre = delusional disorder.”

But in the DSM-5 era, this is no longer the way things are done.

3.1.2 DSM-5 / DSM-5-TR: Adjusting the Role of “Bizarre”

In DSM-5 and DSM-5-TR:

  • Delusional Disorder:
    • No longer requires delusions to be “non-bizarre only.”
    • If the content is bizarre → you add the specifier “with bizarre content.”
  • Bizarre delusions are still present in descriptions of psychotic features, but they are no longer an automatic lock for schizophrenia.

Short summary for your article (very important):

Today, “bizarre content” is used as a specifier / descriptor,
not as a “magic portal” where whenever it appears = must be schizophrenia.

You can include a small comparison table like:

Old DSM EraDSM-5 / DSM-5-TR Now
Delusional Disorder: focused on non-bizarreDelusional Disorder: bizarre allowed → label as “with bizarre content”
Bizarre delusion easily pushed diagnosis toward schizophreniaBizarre delusion = content label, can appear in multiple disorders

3.2 Delusional Disorder (DSM-5-TR Logic in Real Use)

Practically, when clinicians diagnose Delusional Disorder, they usually think in this sequence (which you can write out clearly for readers):

3.2.1 Step 1 — Is There a Delusion Lasting ≥ 1 Month?

  • It’s not just a fleeting odd thought.
  • It is a stable false belief that persists for at least 1 full month
    → This is to exclude very brief psychotic episodes (like Brief Psychotic Disorder).

3.2.2 Step 2 — Has the Person Ever Met Criteria for Schizophrenia?

Schizophrenia Criterion A involves:

  • Delusions
  • Hallucinations
  • Disorganized speech
  • Grossly disorganized / catatonic behavior
  • Negative symptoms

If the patient has previously had a clear full picture of schizophrenia:

  • Then we do not call it Delusional Disorder.

In simple terms:

  • Delusional Disorder = delusion is the main star.
  • Schizophrenia = delusion is just one of several main cast members in a big package.

3.2.3 Step 3 — Overall Functioning “Breaks Mainly in Areas Hit by the Delusion”

Work / social life / self-care are generally still somewhat maintained.

The main problems are:

  • Relationships with people pulled into the delusional content
  • Stress / preoccupation centered on that one main issue

3.2.4 Step 4 — Only Then Add the Specifier: Bizarre or Not?

After concluding that yes, this is Delusional Disorder, then we:

  • Assess whether the content is bizarre.
    • If yes → “Delusional Disorder, with bizarre content.”
    • If no → “Delusional Disorder, persecutory type / jealous type / erotomanic, etc., according to theme.”

Important narrative point for the article:

We decide what disorder it is first,
then tag how strange the content is afterward—
not the other way around.

3.3 Schizophrenia — Bizarre Still Matters, But It’s Not the Main Star

In the DSM-5 framework:

Schizophrenia is a disorder that involves:

  • Delusions
  • Hallucinations
  • Disorganized speech
  • Disorganized/catatonic behavior
  • Negative symptoms

All present in a way that:

  • Lasts a long time (≥ 6 months including prodromal phase), and
  • Causes significant functional impairment (work, study, social life, self-care)

3.3.1 Bizarre Delusions in Schizophrenia

They still appear frequently in schizophrenia, but there is no longer any rule like “if present = diagnostic shortcut.”

The angle you can present in your article:

  • Bizarre delusions are a sign that “the system that perceives reality is breaking down severely.”
  • But whether the diagnosis is schizophrenia or not depends on:
    • Are there other symptoms? (hallucinations, disorganization, negative symptoms)
    • Duration
    • Degree of functional decline

You can give comparison examples:

  • A person with bizarre delusions + hallucinations + severely disorganized speech + significant functional deterioration → tends toward schizophrenia.
  • A person with bizarre delusions alone, with other aspects relatively preserved → might fit better with Delusional Disorder with bizarre content (though in real life, detailed assessment is needed).

3.3.2 Stop Using “First-Rank Symptoms = Sole Hallmark” Like the Old Days

In earlier times (the Kraepelin / Schneider era), high emphasis was placed on “first-rank symptoms”, such as:

  • Thought insertion
  • Thought withdrawal
  • Thought broadcasting
  • Passivity phenomena

Many of these have bizarre content, but newer research plus DSM-5 / ICD-11 perspectives show that:

  • Using first-rank symptoms alone to decide on schizophrenia is not accurate enough.
  • Now, the focus is on the overall pattern of symptoms + time course + functional impairment.

You can summarize this for the article as:

The role of bizarre delusions in modern schizophrenia diagnosis
is that of “an important warning signal,”
not “a binary lock that uniquely determines the diagnosis.”

3.4 ICD-11 — A Perspective That “Does Not Grant Special Status to the Word ‘Bizarre’”

ICD-11 takes an approach where:

  • It provides a broad definition of delusion: a belief that is false, not culturally shared, strongly held, and not easily changed.
  • It does not heavily subdivide delusions into bizarre vs non-bizarre as major categories.
  • When discussing psychotic disorders (such as Schizophrenia or other primary psychotic disorders), it talks about:

    • Delusions
    • Hallucinations
    • Thought disorder
    • Disturbances of self-experience

as clusters of symptoms, rather than focusing on the term “bizarre” as a central axis.

DSM vs ICD-11 comparison your readers will like:

  • DSM-5 / DSM-5-TR
    • Still uses “with bizarre content” as a specifier in some disorders (e.g., Delusional Disorder).
    • It helps describe how strange the content is.
  • ICD-11
    • Does not give “bizarre” as much criteria status as DSM does.
    • Is more interested in “Is there a delusion or not? Is there psychosis or not? How does it affect functioning?”

You can create a small “Clinical Pearl” box like:

  • If you’re using DSM-5-TR → “bizarre” is a tag that helps describe a case. 

  • If you’re using ICD-11 → “bizarre” is a human language descriptor, not a heavily weighted criterion.

4) Subtypes or Specifiers — Related Subtypes/Specifiers

A) Specifier in Delusional Disorder

  • With bizarre content: the delusion has content that is “clearly impossible” under the concept of bizarre (American Psychiatric Association +1).

B) Other Specifiers Worth Mentioning Together (Because Readers Will Ask)

  • Mood-congruent / mood-incongruent psychotic features (in mood disorders with psychosis): whether the content matches or does not match the emotional state (even though not a specifier for “bizarre” itself, it helps differentiate origins).
  • Insight specifiers (e.g., absent insight/delusional beliefs) in some disorders highlight how strongly the belief is held.

C) Common Themes That “Bizarre” Often Overlaps With

  • Passivity phenomena / thought insertion / withdrawal / broadcasting (symptoms that clinicians see as deeply involving self-experience) — ICD-11 comparison work also groups such features as major categories in psychosis.

5) Brain & Neurobiology — Brain and Biology Related to Bizarre Delusions

First, we have to start from a fair and honest position:

Right now, we do not yet have a “brain signature specific to bizarre delusions.”
What we have are models of the brain for delusions in general, and then we interpret that:
if the content becomes out-of-this-world to the point of being bizarre, it likely reflects that “the meaning-making system + the sense of ownership over experiences (self-agency)” are severely disrupted.

Think of it like this:

  • Level 1: The brain misinterprets stimuli a little → mild suspiciousness.
  • Level 2: The brain misinterprets + prediction error is broken → delusions appear.
  • Level 3: The “whole-world model in the head” and the “sense of self” are deeply disrupted → the content jumps into bizarre territory.

We’ll break this down block by block.

5.1 Dopamine & Aberrant Salience — The Brain “Mis-Tags What’s Important”

One of the most influential models for explaining delusions is the Aberrant Salience Model.

Core idea:

  • Normally, the brain uses dopamine as like a “highlighter pen on the cheat-sheet of our life.”
    • What’s important → dopamine rises → the brain turns attention there.
    • What’s unimportant → dopamine stays quiet → the brain lets it pass.
  • In psychosis (especially the schizophrenia spectrum), this dopamine system starts firing at the wrong times / too strongly / at things that should be ordinary.
    → Small things like a person’s glance, car noises, text on the TV get tagged as “Hey, this is really important and meaningful for us!”

Then a second step happens:

When everything “feels unusually important,”
the brain tries to “spin a story” so that there is a pattern.

  • The brain hates empty gaps and unexplained randomness.
  • When it is bombarded by dopamine firing in odd ways, it tries to construct a new narrative:
    • Why is the TV “speaking directly to us”?
    • Why do strangers look at us that way?
    • Why does the porch light blink exactly when we pass?

How does this connect to bizarre content?

  • If aberrant salience is mild and still somewhat filtered by reasoning → we may get delusions that are still roughly “within this world” (non-bizarre).
  • If salience is severely disordered + the logical oversight system (prefrontal/executive function) is weak → the brain begins to allow extreme, physics-defying hypotheses into its model.
    → It’s like the outside world remains the same, but the internal world model is rewritten with no brakes.

Why do antipsychotics help?

  • Most antipsychotic medications work by blocking dopamine D2 receptors in certain brain circuits.
  • When D2 is blocked → the “random highlighting” signals decrease →
    • Strange associative thinking lessens.
    • Preoccupation with illusory patterns reduces.
    • The intensity of delusions decreases (they don’t vanish instantly, but the driving force behind them is reduced).

You can phrase this in reader-friendly language like:

Dopamine doesn’t directly “create madness,”
but it makes the brain feel that “this must mean something.”
When there are question marks everywhere, the brain writes its own story.
And if the distortion in this system is strong enough, the story that gets written can cross the line from “just odd” to “straight-up impossible” = bizarre.

5.2 Prediction Error / Bayesian Brain — When the Brain Updates Beliefs the Wrong Way

Another common model is the idea that the brain is a prediction machine that operates on Bayesian principles.

Simplified version:

  • The brain always has “a model of the world (prior beliefs).”
  • Whenever a stimulus comes in → the brain compares it with the model →
    • If it matches → okay, carry on.
    • If it doesn’t match → a “prediction error” arises = the difference between what was expected and what was seen.
  • Then the brain has to decide whether to:
    • Update the belief to match the new data, or
    • Treat the new data as untrustworthy and discard it.

In typical people:

  • When a strange event happens that is “a bit weird” → the brain sometimes shrugs and moves on.
  • Or thinks, “Huh, that’s odd, but probably a coincidence.”

In psychosis:

  • The balance in how beliefs are updated is disrupted.
    • Sometimes the brain gives too much weight to weird prediction errors.
    • Sometimes it drastically changes beliefs to explain what might actually just be noise.

Connection to bizarre delusions:

  • The brain starts shifting beliefs, not only at the level of “This person probably doesn’t like me,”
    but up to “The entire world is a simulation created to test me.”
  • Instead of small, localized updates, the brain chooses to rewrite the entire framework of reality.

To illustrate:

  • Normal update:
    “He looked at me strangely → maybe he’s annoyed or thinking about something.”
  • Non-bizarre delusion update:
    “He looked at me strangely → he must be one of the people assigned to track me.”
  • Bizarre delusion update:
    “He looked at me strangely → everyone in this world is an agent from another system that created this fake world.”

A tone you can use in your article:

In bizarre delusions, the brain doesn’t just change “a few thoughts.”
It changes “the fundamental rules it uses to interpret reality.”
It’s like switching from “The world is round” to “The world is a game simulation where we are the main NPC.”

5.3 Network-Level Dysfunction — When Brain Networks Talk Out of Sync

We’ve covered dopamine and prediction as broad principles. Another critical layer is that “the brain is a network,” not separate pieces working in isolation.

Three networks often discussed in the context of psychosis:

1. Default Mode Network (DMN)

  • Related to self, internal thinking, daydreaming, and storytelling about “me.”

2. Salience Network

  • Detects what is “salient/important” and shifts attention there.

3. Central Executive Network (CEN)

  • Lateral prefrontal cortex (e.g., dorsolateral prefrontal) → handles reasoning, planning, and filtering thoughts.

In normal functioning:

  • DMN tells stories about us.
  • The Salience network flags, “This is important; look here.”
  • CEN controls and checks, “Is this story the brain is telling logical?”

In psychosis:

  • Research indicates disconnections or abnormal over-connections between these networks:
    • Salience network mislabels random events as “important.”
    • DMN weaves those events into narratives that are “about us personally.”
    • CEN is weakened → logical checking fails → the narratives are allowed to drift far from reality.

Observable behaviors:

  • Jumping to conclusions: seeing a tiny piece of data and immediately inferring a huge conclusion.
  • Interpretation bias: tendency to interpret events as personally significant or having hidden messages.
  • Cognitive inflexibility: once a belief is formed, it’s very hard to change (once believed = believed).

For bizarre delusions:

  • When these networks are severely disrupted at the level of “core self / world model,”
    → the link between the real world and our understanding of it breaks.
    → Belief content can drift into the zone of “could never happen,” yet the brain does not register it as excessive.

You can use this metaphor:

Imagine a company:

  • Salience = HR department highlighting who/what is important
  • DMN = PR department writing narratives that give the company its image
  • CEN = accounting + legal, checking numbers and correctness

If one day HR randomly picks people and announces, “This person is actually the true CEO,”
PR will write long stories making them sound crucial,
while accounting + legal fall asleep → no one brakes the narrative.
The company starts living inside its own storyline.
This is similar to what happens in the brain when bizarre delusions appear.

5.4 Self-Disturbance / Agency — When “Ownership of Thoughts/Body” Breaks

This is the key topic for explaining bizarre symptoms related to “thoughts”, such as:

  • Thoughts being pulled out of the head (thought withdrawal)
  • Someone putting thoughts into our head (thought insertion)
  • Thoughts being broadcast so that others can hear them (thought broadcasting)
  • The body being controlled from outside (passivity phenomena)

What does the brain normally do behind the scenes that we don’t notice?

Every time we think/move/feel, the brain generates a subtle sense that:

  • “This is my own thought.”
  • “This is a movement I intended to make.”

These are the sense of agency and the sense of ownership:

  • Agency = I am the one performing the action.
  • Ownership = It belongs to me.

In psychosis (especially where bizarre passivity phenomena are present):

  • The systems that create these senses become disordered.
  • The brain still “sees” thoughts and actions happening, but mislabels whose they are.

For example:

  • A thought pops into the head (which is a normal process),

but self-monitoring is weak → the brain interprets it as:

“This is not my own thought. Someone put it there.”

  • The body suddenly moves (e.g., tensing, moving fingers without conscious planning),

and a glitch in self-agency makes the person feel:

“Something/someone is forcing me to move.”

Circuits involved (very roughly, useful for your article):

  • Fronto-parietal network: monitors awareness of one’s own movements; separates self vs other.
  • Temporoparietal junction (TPJ): helps decide whether information is “from me or from outside.”
  • Insula and interoceptive circuits: sense internal bodily signals (heartbeat, breathing, etc.) and integrate them into a sense of “being this person.”

When these circuits go wrong:

  • Sensorimotor/thought/feeling data still comes in, but it is “tagged incorrectly.”
    • Thoughts → tagged as “belonging to someone else.”
    • Actions → tagged as “forced by an external agent.”
    • Fear → tagged as “caused by an outside controlling force.”

This is where bizarre delusions like “someone is controlling my thoughts/body using supernatural powers or advanced devices” can arise quite organically from a brain-function perspective. It’s not that the person wants to think strangely, but that the “self vs not-self labeling system” is genuinely malfunctioning.

A neat summary you can write:

Bizarre delusions in the passivity phenomena cluster
are the result of a brain that still perceives thoughts and movements, but no longer accepts them as its own.
When self-agency disappears, that empty space gets filled with out-of-this-world explanations.

6) Causes & Risk Factors — Causes and Risk Factors of Bizarre Delusions

Here, think broadly in this framework:

We are not looking for causes “specific only to bizarre.”
We are looking at factors that make someone vulnerable to psychosis/delusions,
and when the system fails badly enough, the content can drift into bizarre territory.

A macro framework that always works is the Biopsychosocial model:

  • Bio = genetics + brain + chemistry
  • Psycho = personality, cognitive style
  • Social = environment, stress, trauma, drugs, etc.

6.1 Genetics and “Vulnerability” (Genetic Vulnerability)

There is no single “bizarre gene” that makes a person have bizarre delusions.

But there is polygenic risk for psychosis/schizophrenia spectrum in general:

  • If a first-degree relative (parents, siblings) has a psychotic disorder → the risk increases.
  • If one identical twin has it → the other twin’s risk is clearly higher than the general population (but still not 100%).

The key concept:

Genes do not say, “You must get sick.”
Genes say, “Your threshold is thinner than others when environmental factors hit.”

You can explain this to readers as:

  • Genetics = “thickness of the wall.”
  • Stress / drugs / trauma = “force of impact.”
  • If the wall is thin + impact is strong → there’s a higher chance of it breaking into psychosis/delusions.
  • How bizarre the belief becomes depends on how deeply the systems of self/world models are damaged.

6.2 Stress, Environment, and Life Events

A commonly used model: Stress–Vulnerability Model

People with vulnerability (from genetics/brain/other factors), when exposed to high and prolonged stress, such as:

  • Chronic stress from work/family
  • Social isolation
  • Bullying/neglect in childhood
  • Repeated trauma (e.g., abuse, violence)

A vulnerable brain copes worse with stress:

  • Dopamine/glutamate systems and the HPA axis (stress axis) get repeatedly strained.
  • Sleep disruption, irregular eating, unmanaged stress → further erode regulation.

How does this relate to bizarre?

  • If stress is prolonged + vulnerability is high → the risk of a psychotic break increases.
  • If that break affects self-experience and the world model deeply,
    → the explanations the brain constructs to make sense of the world at that time can reach bizarre levels.

In your article, you can add a small section like:

“Stress is not the sole cause, but it is like the flame that ignites the fuel in an already vulnerable brain.”

6.3 Substances, Medications, and Medical Conditions (Must Always Rule Out)

This section is very important when writing for the general public/students:

A) Substances and Stimulants

  • Cannabis (especially high-potency THC):
    • Increases the risk of psychosis in vulnerable individuals.
    • Some people will experience delusions/hallucinations even without prior history.
  • Amphetamines, cocaine, MDMA, etc.:
    • Strongly stimulate dopamine/monoamines → can trigger psychotic episodes.

In some cases, content arising from substance-induced psychosis can also be bizarre,
but may show a pattern of “comes fast, goes fast” or is clearly linked to periods of use.

B) Certain Medical Medications

  • High-dose steroids, some CNS-affecting drugs
    → can produce psychotic symptoms in certain individuals.

So when clinicians see delusions (bizarre or not), they must ask:

  • What medications were recently started?
  • What medications were stopped?
  • Any toxic exposure?

C) Physical/Neurological Conditions

  • Encephalopathy, brain tumors, certain epilepsies, autoimmune encephalitis, etc.
    → all can cause psychosis/delusions.
  • In older adults: delirium and dementia can also come with delusions/hallucinations.

Key point you can embed in your article:

Whenever psychosis/delusions appear, we should not rush to conclude “this is primary psychiatric illness.”
There must always be a step to rule out medical / neurological / substance causes first.

Then you can comment:

In theory, bizarre content can appear in both primary psychotic disorders and secondary psychosis.
But other patterns (age at onset, co-factors, physical symptoms, etc.) help differentiate them.

6.4 Personality and Cognitive/Psychological Factors

These are not stand-alone causes, but they are things that “push and support” delusions to solidify.

6.4.1 Reasoning Bias — “Quick to Believe, Collects Little Data”

Research in psychosis has found classic reasoning biases such as:

  • Jumping to conclusions (JTC):
    • Making a firm conclusion with very little data → “It must be like this.”
    • Rarely seeking additional evidence.
  • Bias toward confirmatory evidence:
    • Preferring to collect only information that fits the existing belief.
    • Disconfirming data → often devalued or considered unreliable.

Result:

Once a delusion starts to form a little,
instead of being checked, it gets “fed” by these biases
and hardens into a full-blown belief.

6.4.2 Attribution Bias — Blaming Others/World Rather Than Chance

Some people have a tendency to:

  • Interpret negative events as “someone intentionally did this to me” rather than “it was a coincidence.”
  • When something odd happens, their brain doesn’t choose neutral explanations like “coincidence,”
    but instead picks explanations involving clear intent → a fertile ground for persecutory delusions to grow.

If network function/dopamine/self systems are also strongly impaired → the content constructed may cross over into bizarre.

6.4.3 Intolerance of Uncertainty — Can’t Stand “Not Knowing”

Some people:

  • Cannot tolerate ambiguity.
  • Want answers right now, even if those answers are extreme.
  • The brain prefers to “believe something extreme” rather than stay in an ongoing “I’m not sure” state.

This is the playing field where delusions like to form:

  • High stress
  • High uncertainty
  • Strong pressure to have an explanation
    = a belief that sometimes crosses the line from plausible → implausible → impossible.

You can summarize this as:

Cognitive factors do not create bizarre delusions from nothing,
but they act like “glue and steel” that shape distorted thoughts into strong structures.
Combined with a brain driven by abnormal dopamine + broken networks, the resulting beliefs are ready to drift far away from shared reality.

7) Treatment & Management — Treatment and Management (System View: Acute → Maintenance)

In slightly business-flavored language:

“The goals are risk containment + symptom de-escalation + functional recovery.”

7.1 Initial Risk Assessment

  • Assess risk of harm to self/others, self-care ability, risk of exploitation, and neglect of physical illness.
  • If there is severe agitation/paranoia: prioritize safety management first (crisis pathway).

7.2 Medication (Pharmacotherapy)

  • Antipsychotics are the mainstay for treating delusions in psychotic disorders (especially when conviction is very high and daily functioning is severely impacted) (MSD Manuals).
  • If the context is mood disorder with psychosis: mood stabilizers/antidepressants may be required according to the overall picture (under a physician’s management).

7.3 Psychotherapy (Psychological Interventions)

  • CBT for psychosis (CBTp): does not bluntly argue “true/not true,” but instead works with:
    • Evaluating evidence
    • The meanings that the brain attaches to experiences
    • Coping with distress
    • Reducing safety behaviors that actually reinforce the belief
  • Metacognitive training / interventions targeting reasoning biases can help some individuals in the long term.

7.4 Functional Rehabilitation

  • Family psychoeducation, social skills training, supported employment/education.
  • Managing sleep, reducing substance use, building daily structure.

7.5 When It Is Delusional Disorder “With Bizarre Content”

  • The basic management is similar, but there must be special emphasis on therapeutic alliance, because insight is often low and direct confrontation of the belief can easily damage collaboration.

8) Notes — Key Points for Writing a “Premium” Article

  • Do not use the word “bizarre” as a way to mock or make light of people in educational content. Use it as a technical term:

bizarre = implausible/impossible content.

  • Distinguish these three layers clearly:

    1. Delusion (the structure of the belief)
    2. Theme (persecutory / grandiose / somatic / nihilistic, etc.)
    3. Bizarreness (how impossible the content is)

Readers will immediately “get the system.”

  • DSM-5 / DSM-5-TR shift: Delusional Disorder no longer excludes bizarre content; instead, it uses it as a specifier—this is a key sentence for both SEO and credibility (American Psychiatric Association +1).
  • If you want to include a “Differential diagnosis” section, you can list:
    • Schizophrenia / Schizoaffective Disorder
    • Mood Disorder with Psychotic Features
    • OCD/BDD with absent insight (which can sometimes resemble delusional beliefs) (American Psychiatric Association)
    • Substance/medical-induced psychosis

References Used When Discussing Bizarre Delusions

  • American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) and DSM-5-TR.
    • Provides the definition of the specifier “with bizarre content” for Delusional Disorder as delusions that are clearly implausible, not understandable, and not derived from ordinary life experiences, for example, the belief that someone removed one’s organs and replaced them without leaving a scar (Physiopedia +1).
  • PsychDB – Delusional Disorder.
    • Summarizes DSM-5 criteria and gives clear examples of bizarre content, such as the belief that someone removed and reinserted organs without any wound, and explains the use of the specifier “with bizarre content” in diagnosing Delusional Disorder (PsychDB +1).
  • Medscape – Delusional Disorder: Overview, Diagnosis, Epidemiology.
    • Explains that diagnosing Delusional Disorder in DSM-5-TR can involve adding the specifier “with bizarre content” when the delusional content is clearly implausible and not derived from normal life experiences (eMedicine +1).
  • Cermolacce, M., Sass, L., & Parnas, J. (2010). What Is Bizarre in Bizarre Delusions? A Critical Review. Schizophrenia Bulletin, 36(4), 667–679.
    • A critical review of the concept of “bizarreness,” teasing apart issues of content, understandability/un-understandability, and the patient’s subjective experience. It supports writing a deep analytical section on why “strange content alone” is not enough; one must also consider phenomenology (PubMed +1).
  • Flaum, M., & Schultz, S. (1991). The reliability of “bizarre” delusions.
    • Studies how the label “bizarre delusions” was used to diagnose schizophrenia in older DSM versions, finding problems with inter-rater reliability, which later contributed to DSM-5 reducing its special weight and moving it to a specifier role (ScienceDirect).
  • Fariba, K. A. (2022). Delusions. StatPearls, NCBI Bookshelf.
    • Provides a classic definition of delusions: fixed false beliefs, resistant to contrary evidence, and not consistent with cultural or religious norms—forming the foundation before distinguishing whether content is bizarre or not (ncbi.nlm.nih.gov).
  • Kapur, S. (2003). Psychosis as a State of Aberrant Salience: A Framework Linking Biology, Phenomenology, and Pharmacology in Schizophrenia. American Journal of Psychiatry, 160(1), 13–23.
    • Proposes the aberrant salience model: dopamine dysregulation causes ordinary stimuli to be perceived as abnormally salient, leading the brain to construct delusions to explain these experiences—very useful for supporting the neurobiology section on delusions/bizarre delusions (PubMed +1).
  • WHO (2024). Clinical Descriptions and Diagnostic Requirements for ICD-11 Mental, Behavioural and Neurodevelopmental Disorders. World Health Organization.
    • Provides the ICD-11 definition of delusion and the structure of psychotic disorders, where “bizarre” does not serve as a main diagnostic gate but as descriptive language about content, useful for comparison with DSM-5-TR in your article (Drugs and Alcohol +1).
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