Delusions

1. Overview — What Are Delusions?

Delusions are one of the most central and defining symptoms in schizophrenia and psychotic disorders more broadly. What makes a delusion more than just an “odd” or “distorted” thought is the level of conviction and the fixed, rigid way in which the belief is held, to the point that the person is almost unable to accept any contradictory evidence, no matter how clear the information is.

Clinically, a delusion is a belief that is clearly false or highly implausible at a level that goes beyond what normal thinking could reasonably explain. Examples include believing that a powerful organization is following and surveilling them, that they are being controlled by secret signals, or that a famous person is secretly in love with them despite never having had any contact.

A key characteristic of delusions is their fixed nature. This means that the person does not change their belief even when confronted with ongoing, repeated disconfirming information. This is not simple stubbornness; it is the result of a disturbance in how the brain interprets reality and assigns meaning.

Another crucial point is that a delusion must fall outside of the belief system that is generally accepted within the person’s culture or religion. If a belief is consistent with the norms of their cultural or religious group—even if unusual to outsiders—it is not classified as a psychotic symptom.

In the philosophy of medicine, Karl Jaspers described delusions as having four characteristics:

Believed with “100% certainty” (certainty)

Not altered even when clearly contradicted (incorrigibility)

False or impossible in terms of real-world possibility (impossibility/falsity)

Not fully explainable by normal psychology, such as ordinary fear, stress, or cognitive bias

Currently, DSM-5-TR still relies heavily on these axes to decide what “counts as a true delusion,” especially focusing on two core criteria: falsity (being clearly untrue) and fixed belief (a belief held rigidly without willingness to adjust).

Delusions are not limited to schizophrenia. They can be found in a wide range of conditions, such as:

Delusional disorder (with specific themes such as erotomanic, jealous, persecutory)

Bipolar disorder with psychotic features (during mania or depression)

Major depressive disorder with psychotic features

Substance-induced psychosis, e.g., from methamphetamine, high-potency cannabis

Certain medical conditions, such as encephalitis or tumors in specific brain regions

From the ICD-11 perspective, delusions are categorized as one of the positive symptoms of psychosis, alongside hallucinations, disorganized thinking, and grossly disorganized behavior, which together form the core features for diagnosing schizophrenia spectrum disorders.

The key takeaway is this: a delusion is an experience arising from disruptions in brain circuits, not from imagination, overthinking, or personal weakness. People with delusions live in a “different world-perspective” constructed by their brain and repeatedly reinforced by distorted meanings assigned to ordinary events around them.

All of this makes delusions one of the most complex topics in psychiatry, because they represent a direct disturbance in the “reality-testing system.” They lie at the center of suffering, confusion, fear, and life impact for many individuals globally.

2. Core Symptoms — The Central Features of Delusions

This section is the “skeleton” of what we call a delusion: what turns a particular belief into a “delusional symptom,” rather than just overthinking or simple misinterpretation.

2.1 Fixed False Belief

The most fundamental core:

It is a belief, not a hallucination and not just a fleeting thought. It is something the person insists is true.
It is a belief that is clearly false in terms of fact, or at least extremely unlikely in the real world.
The belief is fixed – it does not change easily with reasoning or over time.

Concrete examples:

Believing that someone is following them all the time, even though there is no evidence at all (no recurring car, no one visibly tailing them).
Believing that there is a “chip implanted in their brain” that controls their thoughts, even though they have never had any surgery.
Believing with 100% certainty that their partner is cheating on them, despite zero actual evidence, and only interpreting normal behavior as “suspicious.”

The crucial point is:

In the general population, we all have odd or insecure thoughts sometimes, such as “They probably don’t like me.” But when new information appears, we can adjust our thinking.
In delusions, the person nails the belief down like a nail into concrete. New information has little to no effect.

2.2 Resistance to Counter-Evidence

This is the hallmark that distinguishes delusions from “ordinary but incorrect” beliefs.

In normal situations:

We might misunderstand something, but when there is strong evidence (CCTV footage, receipts, logical explanations), we hesitate and may adjust our belief.
Our ego might resist a bit, but when reality pushes hard enough, we usually step back.

In delusions:

Contradictory evidence has almost no impact.
Sometimes, the more evidence you show, the more the delusion is reinforced, because the person interprets it as:

“See? Everyone is working together to hide the real evidence.”
or
“The fact that they deny it this strongly proves it must be true.”

Common patterns:

People around them say, “No one is watching you,” and they interpret it as:

“Everyone is colluding and lying.”

A partner tries to prove their innocence, for example by video-calling frequently. The person may interpret this as:

“You’re only doing this to cover up other evidence.”

Summary: A delusion is not just an incorrect idea. It is a reality-interpretation system that is effectively bulletproof against contradictory information.

2.3 Very High Conviction (Abnormally Strong Belief)

Conviction = “How sure are you that this is true?”

Normal beliefs leave room for doubt, e.g., “I think he doesn’t like me… maybe / probably.”
In delusions, conviction is typically at the level of:

“This is 100% true, like gravity.”

Characteristics of conviction in delusions:

The belief is held like a physical fact, such as “fire is hot” or “falling from a building will hurt.”
If asked, “Is it possible that you might be wrong?” the common answers are “No” or “It’s very unlikely.”
The person may know that others find it “implausible,” but still fully believes that in their own case, it is “an exception” to normal rules.

Important to understand:

People with delusions are not “overacting” or “faking it” to get attention.
In their subjective experience, this is reality. Their brain is literally building and maintaining that pattern of meaning.

2.4 Centrality — Impact on Interpretation of Everyday Events

A delusion is not just “one isolated belief.” It becomes the main lens through which the world is viewed.

Centrality means:

The delusion becomes the center of the person’s life narrative.
Events around them—facial expressions, tone of voice, car sounds, news on TV, social media posts—are all interpreted through this lens.

Examples:

If there is a persecutory delusion →

Friends laughing in a room = “They are laughing at me.”
A car driving slowly past = “This car is surveilling me.”
Someone glancing over = “He must be the agent who is monitoring me.”

If there is an erotomanic delusion →

A celebrity’s sad song in an IG story = “They’re sending a message to me.”
A single emoji reply in a comment = “They’re secretly telling me they feel the same way.”

Result:

The entire world becomes a “field of evidence” where everything seems to confirm the delusion.
Many individuals feel like “everything points to the same conclusion,” which further increases their conviction.

2.5 Impact on Daily Life, Work, and Relationships

A delusion that has absolutely no impact at all may be below the threshold of “clinical significance.”
But in real life, delusions usually start to damage multiple areas of functioning, such as:

Daily life

A person with persecutory delusions may be afraid to leave the house, avoid public transport, cover windows, or constantly switch off cameras and microphones.
Someone with somatic delusions may be consumed by repeated medical checks and investigations, leaving little room for other activities.

Work

Paranoia about colleagues → believing everyone is trying to sabotage them or steal their position.
Refusing to collaborate on projects or becoming aggressive because they believe “the boss is targeting me specifically.”
The result: reduced productivity, poor performance, or termination of employment.

Family and romantic relationships

Jealous / infidelity delusions → constant phone checking, attempts to control or confine the partner, tracking location at all times.
Intense conflicts because “no amount of proof is ever enough.”
In extreme cases, this can lead to domestic violence.

Financial status

Repeated health checks (somatic delusions) → large costs for tests, medication, and consultations.
Risky investments driven by grandiose delusions (e.g., believing they have a “genius master plan” for investing) → very high financial risk.

2.6 Associated Features

Beyond the delusion itself, there is usually a “cluster” of accompanying symptoms that significantly increase the person’s suffering.

1) High anxiety and paranoia

A persistent sense that “the world is unsafe.”
Fear of being harmed, monitored, criticised, or controlled.

2) Sleep problems

Difficulty falling asleep because the brain is hyper-aroused, ruminating about who is doing what to them.
Nightmares or frequent awakenings.

3) Depression / hopelessness

Feeling isolated because no one “understands the truth” as they do.
Believing that the future is blocked, e.g., “They will keep destroying my life forever.”

4) Risk of self-harm or harm to others (depending on delusional content)

Severe persecutory delusions: the person may believe they must “strike first in self-defense.”
Nihilistic / hopeless delusions: the person may feel “everything is over,” increasing risk for self-harm or suicide.

Overall: the core symptoms of delusions are not just “wrong thinking.” They form a tightly interconnected set of beliefs + interpretations + emotions + behaviors, creating an alternate world in which the person becomes trapped.

3. Diagnostic Criteria — How Delusions Are Diagnosed

This section summarizes what clinicians (psychiatrists / clinical psychologists) look for before concluding that “this is a delusion in the clinical sense,” not just a strange or intense belief.

3.1 Symptom-Level Criteria for Delusions

In general, when evaluating “Is this a delusion?” clinicians use DSM-5 / ICD-11-type concepts (in summarized form) and look at how strongly the following elements are present:

Clearly false or highly improbable belief
Examples:

Believing they are the child of a king in another country despite no evidence at all.
Believing that every passerby is a secret agent sent to monitor them.

High conviction

Repeated questioning leads to the same firm insistence.
If asked, “Is it possible that you might be mistaken?” the usual answers are “No” or “Almost impossible.”

Not changed by contrary evidence

Even after evidence is shown (video recordings, multiple independent testimonies, medical tests), the person still holds the same belief or distorts the evidence to fit the belief.

Not explainable by culture/religion/sect

If a belief is shared by most people in a community (e.g., specific religious beliefs), it is not considered a delusion.
A true clinical delusion often remains strange even within that culture’s own belief frame.

Causes distress or impairment in functioning (clinical significance)

Losing a job because of a belief that “my boss and a secret organization are conspiring against me.”
Marriage breakdown due to delusional jealousy.
Becoming socially withdrawn and avoiding others because of fear of surveillance.

Summary: If there is “a false belief + high conviction + resistance to change + not culturally shared + life impairment,” it usually meets criteria for a clinical delusion.

3.2 Delusional Disorder (Detailed DSM-5-Style Summary)

Delusional Disorder = a condition where delusions are the main “star symptom”, without the full range of other schizophrenia features.

Key criteria (summarized for explanation):

At least one delusion lasting ≥ 1 month

Theme may be persecutory, erotomanic, somatic, jealous, grandiose, or mixed.

No history of a full schizophrenia episode

No prominent, persistent disorganized speech
No heavy, pervasive hallucinations or marked negative symptoms

Overall functioning is still “fairly okay” compared with schizophrenia

Many people with delusional disorder can still work and maintain some social life, but the delusion heavily disrupts certain domains (e.g., relationships, work).

If hallucinations are present, they are mild and related to the delusional theme

For example, believing that insects are under the skin and feeling sensations of bugs crawling (tactile hallucinations).

The disturbance is not due to substances, medications, or other medical conditions

Causes like drugs or brain disease must be ruled out.

Concrete picture:

A person firmly believes for months or years that “my neighbor is intentionally attacking me with microwave beams.”
They can still go to work and talk sensibly about other topics, but the “neighbor harming me” issue dominates their life. → This is typical of delusional disorder.

3.3 Schizophrenia (Connection with Delusions)

In schizophrenia, delusions are one of the “three main pillars”, together with:

Hallucinations (e.g., hearing voices)
Disorganized speech (speech that is so disorganized or tangential that others cannot follow)
Delusions

DSM-5-TR states that:

At least 2 core symptoms must be present, and at least one of them must be:

Symptoms must be present continuously for at least 1 month (active phase).
The total course of the illness (including prodromal and residual phases) must be ≥ 6 months.
There must be functional decline (e.g., inability to work, study, or maintain relationships).

In summary:

In schizophrenia, delusions are one of the key signs of psychosis.
But they usually appear alongside disturbances in thinking, speech, behavior, and negative symptoms.

3.4 ICD-11: Delusions as Positive Symptoms

ICD-11 views psychotic disorders with an emphasis on prominent and persistent positive symptoms, which include:

Delusions
Hallucinations
Disorganized thinking (or speech that reflects disordered thinking)
Grossly disorganized behavior

To diagnose “schizophrenia spectrum / primary psychotic disorder”:

At least one of these positive symptoms must be clearly present and persistent.

Therefore, in ICD-11, delusions are also a major indicator of psychosis.

3.5 Differentiating Delusions from Other Phenomena (Differential)

This is crucial when explaining to the general public that “delusion vs overthinking vs strong belief” are not the same.

1) Overvalued Ideas

These are beliefs that are held very strongly but still leave some room for change.
The person can still admit, “I might be wrong,” even if they don’t like to.
Example: someone who is convinced that they must eat only a certain diet to stay healthy, but with strong, consistent medical evidence across doctors, they can still be shifted.
This does not meet the criteria for delusion because the belief still has flexibility and is not fully disconnected from reality.

2) Obsessions (OCD)

Obsessions are thoughts/images/impulses that intrude against the person’s will, and they know the thoughts are “unreasonable,” but they cannot stop them.
Most people with OCD have some level of insight, such as “I know it’s over the top, but I really can’t stop worrying.”
This is the opposite of delusion, where the person believes the content is “fact.”

Examples:

OCD: “If I don’t wash my hands 20 times, my mother might die.” → The person knows it doesn’t make rational sense, but anxiety forces them to do it.
Delusion: “My neighbor has definitely installed secret cameras in my house.” → The person believes this as fact and does not see it as weird.

3) Culturally / Religiously Shared Beliefs

Beliefs about spirits, magic, or sacred entities can be normal within certain communities.
If a belief is shared by most members of a community, it is not considered a delusion, even if outsiders see it as strange.
A clinical delusion, by contrast, is a belief that is unusual even within that cultural group.

For example:

In a community that believes in spirits, one person says, “Only I have been chosen by a secret organization from Mars to use these spirits as agents to control humanity.” → This begins to fall into delusional territory.

Summary of Sections 2 + 3

If you compress it into a short checklist for content/infographics:

Delusion =

A belief that is false or highly implausible
Held with high conviction (treated like a flat fact)
Not changed even when confronted with strong contradictory evidence
Not explained by cultural or religious norms
Causes distress or impairment in work, relationships, or daily functioning
Becomes the main lens through which the person interprets the world
Often accompanied by paranoia, anxiety, insomnia, and depression

In diagnostic terms:

Delusions can occur in schizophrenia, bipolar disorder, depression with psychotic features, delusional disorder, substance-induced psychosis, etc.
In Delusional Disorder, delusions are the main feature, while other functioning can remain relatively intact.
In Schizophrenia, delusions are one of the “core symptoms,” alongside hallucinations and disorganized speech.

4. Subtypes or Specifiers — Types of Delusions

DSM-5-TR describes several main themes of delusions commonly seen in schizophrenia and delusional disorder, roughly 7 core types plus mixed/unspecified. Healthline+2NCBI+2

4.1 Persecutory Delusions

Belief that someone is “trying to harm / persecute / frame / surveil” them.
They may think that a powerful organization, the government, co-workers, or neighbors are monitoring them or installing bugs.
This is the most common type in both schizophrenia and delusional disorder. Verywell Health+1

4.2 Referential Delusions

Belief that news on TV, songs on the radio, social media posts, or minor actions of others are “sending special messages to them.”
Example: believing that a DJ is playing a particular song specifically to warn them, or that a stranger’s post on X is a secret communication targeted at them.

4.3 Grandiose Delusions

Belief that they possess world-level abilities, power, or status—for example, being God’s special representative, a historic-level genius, or a savior of humanity.
Some believe they possess vast wealth or have much higher status than in reality. NCBI+1

4.4 Erotomanic Delusions

Belief that someone (often a celebrity or high-status person) is “secretly in love” with them.
Ordinary behaviors are interpreted as signs of love—e.g., a brief glance is interpreted as a meaningful signal.

4.5 Nihilistic Delusions

Belief that the world is ending, that their body is rotting, or that their internal organs are gone.
In extreme cases, this develops into Cotard syndrome: believing they are already dead or do not exist. Symptom Media

4.6 Somatic Delusions

Belief that they have a serious physical illness, despite no abnormal findings.
Examples: believing they have parasites under their skin, that they emit a terrible body odor even though others do not notice, or that their body is horribly deformed. NCBI+1

4.7 Bizarre Delusions

The content is so strange that it could not realistically happen in the real world, for example:

Believing that thoughts are being stolen from their mind (thought withdrawal).
Believing that someone else is “inserting thoughts” into their mind (thought insertion).
Believing that their actions are being controlled by external forces (“delusions of control”). KSU Faculty+1

4.8 Special Syndromes

Capgras syndrome – Belief that a close person has been replaced by an imposter or alien double.
Frégoli syndrome – Belief that different people they encounter are actually the same person in disguise.
Cotard syndrome – Already mentioned under nihilistic delusions (belief that they are dead or do not exist). Symptom Media

4.9 Mixed / Unspecified

Mixed type – Several delusional themes are clearly present together.
Unspecified – Delusional content is present but does not fit any theme clearly, or there is insufficient information to classify it.

4.10 Mood-Congruent vs Mood-Incongruent

In bipolar disorder / major depression with psychotic features, delusions are further classified as:

Mood-congruent – Content matches the mood. For example, in severe depression: delusions of impending bankruptcy or being morally unforgivable.
Mood-incongruent – Content does not match the mood. For example, being severely depressed but having grandiose delusions.

5. Brain & Neurobiology — Brain Mechanisms of Delusions

Delusions are not “random strange thoughts” that pop up out of nowhere. They arise from multiple brain circuits that have been tuned away from normal functioning, especially systems involved in:

Assigning meaning (salience)
Anticipating events (prediction)
Evaluating reality (reality testing)
Memory and context (context encoding)
Inhibiting internal noise in the brain

All of these systems are interconnected; if one point in this network becomes “mis-tuned,” ordinary thoughts can be misinterpreted as “important,” “dangerous,” or “special,” leading over time to fully formed delusions.

5.1 Aberrant Salience & Dopamine — Disturbed “Significance Signaling”

One of the most influential theories in psychosis is Aberrant Salience.

Core idea:

Under normal conditions, dopamine “marks” stimuli that are important for survival: food, danger, reward.
In psychosis, dopamine fires too much in situations that should not be significant.

Result:

Everyday stimuli like a glance from a friend, a passing car, or a message from someone are “tagged” by the brain as extremely important or meaningful.
The person begins to feel:

“Something is definitely happening, but I can’t explain what it is.”

When the brain repeatedly receives these “wrong importance” signals, it tries to construct an explanatory story to make sense of the world again. This is the origin point of delusion.

Why is dopamine abnormal?

Imbalance in the mesolimbic pathway leading to the ventral striatum
Dysfunction in the prefrontal cortex, which should regulate dopaminergic activity
Abnormal receptor binding
Low-grade inflammation in the brain

The net effect is that the brain over-assigns meaning to ordinary stimuli, giving rise to strange beliefs with very high conviction.

5.2 Predictive Coding / Bayesian Brain Model — A Brain That Mis-Times Its Predictions

Recent research shows that the human brain functions as a “prediction machine.”

The brain relies on two key components:

Prior beliefs (internal models of the world)
Sensory input (real-world data)

It combines these to generate what we experience as “reality right now.”

In psychosis:

The weight of prior beliefs can be abnormally high → when a wrong idea arises, the brain believes it strongly.
Or in early psychosis, priors may be weak, making the world feel chaotic and meaningless → the person may create new beliefs to fill this gap (delusion formation).

Illustration:

Normal brain: “Noise from next door = people talking normally.”
Brain with distorted predictive coding: “Noise from next door = a warning signal; someone is monitoring me.”

The brain is not “lying”; it is misinterpreting, because its predictive system is set to the wrong parameters.

5.3 Neurocircuitry of Delusions

1.Striatum / Basal Ganglia

Source of dopamine signaling
Tags stimuli with importance
If it malfunctions → salience is mis-assigned → delusion formation begins

2. Prefrontal Cortex (DLPFC / vmPFC)

Responsible for:

Rational thinking
Reality testing
Cognitive flexibility

When the PFC is weak, it cannot properly “audit” incorrect beliefs, so delusions become rigid very quickly.

3. Hippocampus

Stores context such as where, who, and when
If the hippocampus is overactive (as often found in psychosis), it can generate faulty associations, for example:

Small, unrelated events are interpreted as “definitely connected.”

This underlies referential delusions.

4. Default Mode Network (DMN)

The self-referential system, involved in thinking about oneself
If DMN connectivity with sensory networks is abnormal, people may interpret many events as being “about me.”

This is the basis of referential and grandiose delusions.

5.4 Glutamate, GABA, and Neurochemical Balance

Dopamine is not the only player.

Glutamate (NMDA receptor hypofunction)

Makes some brain circuits overactive and noisy.
Interpretation of information becomes unstable and oscillatory.
The person feels the world is “confusing, chaotic, and unreliable,” creating conditions for delusions to organize that chaos.

GABAergic Dysfunction

GABA is the brain’s braking system.
When brakes fail, the brain is flooded with noise, thoughts jump around, and connections are made too easily between unrelated things.
This is a foundation for disordered thinking and the creation of meanings that are not actually there.

5.5 Neuroinflammation & Oxidative Stress

Modern research has found:

Overactivation of microglia
Chronic low-grade inflammation in the nervous system
Combined with oxidative stress, these factors damage prefrontal and hippocampal circuits

All of this impairs cognitive control, making delusional beliefs “stick” for longer.

6. Causes & Risk Factors — Why Do Delusions Develop?

Delusions do not have “one single cause.” They arise from a complex combination of:

(biology + psychology + social context + life experiences)

6.1 Biological / Genetic Factors

Genetic Loading

Having a first-degree relative with schizophrenia → risk increases 8–12 times.
Having relatives with bipolar disorder plus psychosis → risk also rises.
Multiple genes are involved, e.g., COMT, DRD2, DISC1.

Neurodevelopmental Risk

Risks present from before birth, such as:

Birth hypoxia (lack of oxygen during delivery)
Maternal viral infections (e.g., influenza) during the second trimester
Low birth weight
Chronic maternal stress during pregnancy

These can lead to dopamine and glutamate systems developing in an “over-sensitive” way.

Substance-Induced Sensitization

Certain substances can directly trigger psychosis, especially:

Methamphetamine
High-potency cannabis
Cocaine
Ketamine (NMDA blockade → mechanisms similar to aspects of psychosis)

For those already at risk, substance use can rapidly precipitate delusions.

6.2 Psychological Factors

Trauma & Early Adversity

Serious childhood experiences such as:

Physical abuse
Neglect
Bullying
Growing up in an unsafe family environment

These shape the brain to interpret the world as “dangerous,” strongly predisposing to persecutory delusions.

Cognitive Biases (distorted thinking styles)

These are key roots of delusion formation:

Jumping to Conclusions (JTC)
→ Making decisions quickly with minimal information—for example, seeing two people talk and immediately concluding “They are talking about me.”

Externalizing Bias
→ Attributing problems to others or the external world rather than oneself → supports persecutory themes.

Belief Inflexibility
→ Rigid belief structures that do not shift easily → ideal ground for delusions to develop.

Distorted Self-Schema

Viewing oneself as worthless → can feed nihilistic or depressive delusions.
Viewing the world as fundamentally unsafe → promotes persecutory delusions.

6.3 Social / Environmental Factors

Urbanicity (Growing Up in a Big City)

People raised in large cities have higher psychosis risk compared to those in rural areas, likely due to:

Chronic stress
Social isolation
Social pressure
Exposure to pollution/inflammatory factors

Migration & Discrimination

Migrants or minority groups who experience high levels of discrimination:

Face ongoing threats
Show increased risk of persecutory thinking and delusions.

Social Isolation

Lack of real-world social interaction
No “reality check” from others
Misinterpretations accumulate and harden into delusional beliefs.

6.4 Medical & Neurological Factors

Certain medical conditions can produce delusions, such as:

Dementias (Alzheimer’s disease, Lewy body dementia)
Brain tumors in frontal/temporal regions
Certain types of epilepsy (e.g., temporal lobe epilepsy)
Metabolic conditions, such as hepatic encephalopathy and uremia
Autoimmune encephalitis (e.g., anti-NMDA receptor encephalitis)

If delusions appear suddenly, especially in older adults, medical causes must be urgently investigated.

Delusions = the result of a “brain that is misinterpreting the world’s signals.”

Causes include:

Abnormal dopamine signaling
Distorted predictive coding of reality
Imbalance in prefrontal–striatum–hippocampus circuits
Glutamate/GABA dysregulation
Brain inflammation
Genetics + trauma + loneliness
Substance use
Medical/neurological illnesses

So a delusion is not just “weird thinking” or “overthinking.”
It is the systematic outcome of brain processes misreading the world.

7. Treatment & Management — Caring for and Treating Delusions

This is an overview for understanding and content-writing purposes, not personal medical advice. If someone appears to have these symptoms, they should consult a psychiatrist or clinical psychologist for a proper evaluation.

7.1 Pharmacological Treatment

Antipsychotics (primarily D2 blockade) floridabhcenter.org+1

Typical / First-generation (e.g., haloperidol, fluphenazine)

Effective in reducing positive symptoms (delusions, hallucinations).
Higher risk of EPS, dystonia, and tardive dyskinesia.

Atypical / Second-generation (e.g., risperidone, olanzapine, quetiapine, clozapine, etc.)

Reduce delusions and other symptoms.
Different side-effect profiles (weight gain, metabolic changes, sedation, etc.).

Main goals for delusions:

Reduce the intensity of aberrant salience, thereby lowering the tension and conviction surrounding the delusion.
Treatment is often long-term, especially in chronic schizophrenia or longstanding delusional disorder.
Clozapine is used in treatment-resistant psychosis (when other antipsychotics fail).

7.2 Specialized Psychotherapy — CBT for Psychosis (CBTp)

CBTp has very strong evidence over the past 10–20 years. It is used alongside medication, not as a full replacement. Taylor & Francis Online+4mirecc.va.gov+4cci.health.wa.gov.au+4

Main goals:

Reduce conviction (how strongly the delusion is believed) and centrality (how central it is to one’s life).
Increase cognitive flexibility.
Reduce distress, even if the delusion does not disappear completely.

Key techniques:

Normalization – Explaining that psychotic experiences are not unique and that many people have similar symptoms, reducing shame and catastrophic interpretations (not “cursed” or “hopelessly insane”).
Formulation-driven CBTp – Viewing delusions as outcomes of trauma, core beliefs, stress, sleep disruption, and social factors, and building a tailored case formulation.
Verbal challenge & behavioural experiments – Exploring evidence “for” and “against” the belief, and designing small real-life experiments to test the hypothesis.
Safety learning – Reducing associations of stimuli = danger via graded, safe exposure. OSF+1

7.3 Family Intervention & Psychoeducation

Educating families about what delusions are, correcting misconceptions like “just stubborn / fantasizing / lazy.”
Teaching communication skills and reducing expressed emotion (criticism, hostility, sarcasm) to prevent relapse.
Helping families separate “the person” from “the illness.”

7.4 Everyday Management Principles

Avoid head-to-head reality arguments – Saying “That’s not true!” directly often makes the delusion more rigid.
Reflect feelings before beliefs – e.g., “It sounds like you feel very unsafe thinking that someone is following you.”
Focus on safety – If delusional content involves risk (e.g., believing they must kill someone before being killed), professional safety management is essential.
Strengthen routine and self-care – Adequate sleep, avoiding substances, structured daily routines, and stress reduction are crucial.

8. Notes — Additional Points to Know (for Content & Public Education)

Delusions exist on a continuum with normal beliefs:
From odd but flexible ideas → overvalued ideas → fully rigid delusions.
Cultural context is critical:
A belief that looks “bizarre” to outsiders may be central to a particular community’s worldview.
Insight has multiple levels:

Some people believe with 100% certainty.
Others may say, “I know other people don’t believe this, but I still feel it’s true.”
CBTp often works by gradually enhancing this level of insight.

Delusions do not mean the person is “stupid”:
Many individuals with delusions are intelligent and high-functioning, but their reality-testing in specific areas is disconnected.
Distress and functional impact matter as much as content:
Two people may hold similarly odd beliefs, but one lives normally while the other’s life is collapsing. The latter is of greater clinical concern.
Recovery is possible:
With medication, CBTp, and social support, many people can reduce their conviction in delusions or learn to live alongside them without letting them destroy their lives.
Avoid stigma:
Calling someone “crazy,” “delusional,” “just imagining things” can prevent them from seeking help, allowing the condition to become chronic.

Read Schizophrenia

📚 Academic References (Formal Sources)

(Based on psychiatry, neuroscience, cognitive science, DSM-5-TR, and ICD-11)

Core Diagnostic & Classification

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). APA Publishing, 2022.
World Health Organization. International Classification of Diseases 11th Revision (ICD-11): Schizophrenia spectrum and other primary psychotic disorders. WHO, 2020.

Delusions — Conceptual & Clinical

Jaspers, K. General Psychopathology. 1913/1963. (Classical “three axes” concept of delusions)
Oltmanns, T., & Emery, R. Abnormal Psychology. Pearson. (Chapter on delusional thinking)
Garety, P. A., & Freeman, D. (1999). Cognitive approaches to delusions: A critical review. British Journal of Clinical Psychology.
Freeman, D. (2007). Suspicious minds: The psychology of persecutory delusions. Clinical Psychology Review.

Neurobiology of Delusions

Kapur, S. (2003). Psychosis as a state of aberrant salience. American Journal of Psychiatry.
Howes, O. D., & Kapur, S. (2009). The dopamine hypothesis of schizophrenia: version III. Schizophrenia Bulletin.
Stephan, K. E., et al. (2009). Dysconnection in schizophrenia: From abnormal synaptic plasticity to failures of self-monitoring. Schizophrenia Bulletin.
Fletcher, P. C., & Frith, C. D. (2009). Perceiving is believing: A Bayesian approach to explaining the positive symptoms of schizophrenia. Nature Reviews Neuroscience.
Lisman, J. (2012). Excitation-inhibition balance, NMDA hypofunction, and schizophrenia. Neuron.

Cognitive Bias, Interpretation, Predictive Coding

Corlett, P. R., et al. (2010). Predictive coding and delusions. Trends in Cognitive Sciences.
Bentall, R., et al. (2001). Attributional style in persecutory delusions. Journal of Abnormal Psychology.
So, S. H., & Freeman, D. (2015). Cognitive mechanisms contributing to the formation and maintenance of delusions. Clinical Psychology Review.

Trauma & Social Risk Factors

Varese, F., et al. (2012). Childhood adversity and psychosis: A meta-analysis. Schizophrenia Bulletin.
Morgan, C., & Fisher, H. (2007). Environmental factors in schizophrenia: Urbanicity, migration, social adversity. Psychiatry.

Treatment & Management

Wykes, T., et al. (2008). Cognitive behavior therapy for psychosis: Meta-analyses. Schizophrenia Bulletin.
Morrison, A. P. (2004). CBT for people with psychosis. Clinical Psychology & Psychotherapy.
Jones, C., et al. (2012). Psychological therapies for delusions: Systematic review. The Lancet Psychiatry.

🔑

Delusions, Psychosis, Positive Symptoms, Schizophrenia Spectrum, Delusional Disorder, Persecutory Delusions, Grandiose Delusions, Somatic Delusions, Referential Delusions, Thought Insertion, Aberrant Salience, Dopamine Dysregulation, Predictive Coding, Bayesian Brain, Cognitive Biases, Trauma and Psychosis, Neurodevelopmental Risk, Urbanicity, Social Isolation, CBT for Psychosis, Antipsychotic Treatment, Neural Circuits, Prefrontal Cortex Dysfunction, Striatum Dopamine, NMDA Hypofunction, GABA Deficit, Neuroinflammation, Reality Testing Impairment, Clinical Psychology, Psychiatry Education, Mental Health Research

ads-d