Everything You Never Knew About Delusions

What is a Delusion?

A person experiencing a delusion is resolutely holding on to a belief that is clearly false to everyone else. This person will be absolutely, 100% sure that their delusion is real and correct, no matter what. Research has shown that the delusional belief cannot be explained by the person’s cultural or religious background or their level of intelligence. The delusional belief will likely affect the person’s state of mind and behavior. There are many different types of delusions (see below).

People with delusions often appear normal and are able to function in day-to-day life. They are often aware of that their belief is unique (though this is not enough for them to challenge the belief). Because of this, people with delusions tend to hide them and not talk about them so as not to appear odd. Not surprisingly, delusional disorders are thought to be underdiagnosed.

What is the difference between Delusions and Hallucinations?

Delusion, as defined by Merriam-Webster, is a false idea or belief that may be caused by mental illness. This belief continues even when the subject is shown indisputable evidence that contradicts their belief. The beliefs often involve a misinterpretation of perceptions or experiences, and there are many different types. In contrast, a hallucination is defined as a perception of something that is not real, usually arising from disorder of the nervous system or in response to drugs. Hallucinations are most commonly auditory but also include visual, taste, smell, and touch. Types of hallucinations will be covered in a separate post. Thus, the main difference is that a delusion is a false belief while a hallucination is a false perception. Here’s an example of each to illustrate:

  • He wondered if the voices he was hearing were real or if it was a hallucination. (altered perception)
    • An example would be the character of Dr. Daniel Pierce on the show Perception
  • He is living under the delusion that the government is spying on him. (false belief)
    • An example from popular culture would be the character of Mozzie on the show White Collar

Who gets delusions?

Delusions are a symptom of either a medical, neurological, or mental disorder. Delusions occur in quite a few mental illnesses, including Schizophrenia, Delusional Disorder, Schizoaffective Disorder, Schizophreniform Disorder, and brief psychotic disorder, along with Bipolar Disorder, Major Depressive Disorder with psychotic features, Delirium, and Dementia.

What are the types of delusions?

  1. Persecutory Delusion

The most common type is the Persecutory Delusion, formerly known as Paranoid Delusion. Affected individuals believe that someone either has harmed them or wants to harm them. They often believe that they are being prejudged or profiled, and may be convinced that they are being followed, threatened, attacked, maltreated, sabotaged, spied upon, or ridiculed. This type of delusion is most common in Schizophrenia and Delusional Disorder.

Example: A person believes that someone is trying to poison them, and so refuses to eat anything that they have not personally prepared.

  1. Grandiose Delusions

People under a grandiose delusion may be convinced that they are the strongest, richest, greatest, or most intelligent person. They may also believe that they have a special power or talent or have a special relationship with someone famous of powerful. They may even believe that they are a famous person or well-known character. In this type of delusion, the sufferer generally does not know they have lost touch with reality. The delusions tend to be fantastic or supernatural. This type of delusion occurs most often in Delusional Disorder, Schizophrenia, and the manic phase of Bipolar Disorder. True grandiose delusions should not be confused with excessive pridefulness wherein someone overestimates their own abilities or talents.

Example: He jumped off the roof because he was convinced that he could fly with his superman-like powers.

  1. Erotomanic Delusions

In erotomanic delusions, the affected individual mistakenly believes that someone, usually a celebrity or famous person, is in love with them. They often believe that they have had or currently have a romantic relationship with this person. Someone with this type of delusion may collect memorabilia or own every movie their celebrity has starred in, and know all the trivia about that person’s life. People suffering from this type of delusion may become stalkers.

Example: He had never met Angelina Jolie, but he wrote to her twice a day and professed his love for her to anyone who would listen.

  1. Delusion of Control

People under the delusion of control are convinced that an external force, such as another person, group, or government, is controlling their thoughts, feelings, or actions. An example would be when someone commits a crime but insists that “aliens made them do it” or “the devil made them do it.” If they truly believe that to be the reason for their actions, they are suffering from a delusion of control.

  1. Somatic Delusions

In somatic delusions, the affected individual believes that they have a physical illness or that their body is diseased in some way. They may believe that their body is not functioning as it should or that their appearance is abnormal.

Example: Tests proved that he was perfectly healthy, yet he clung to the belief that his internal organs were being eaten by parasites.

  1. Delusions of Reference

In this type of delusion, the affected person interprets casual everyday events, insignificant conversations, objects, or coincidences to have some sort of special meaning only for them. For example, a person might think that the TV anchorwoman is speaking directly to them and conveying a secret message. Sometimes the messages have a grandiose quality. This type of delusion is part of the diagnostic criteria for psychotic illnesses and can also be an indicator of paranoid personality disorder. Similar symptoms can also be caused by drugs and alcohol, so care must be taken during diagnosis.

Example: Whenever Michael sees a black truck, he believes that God is sending him a message.

  1. Delusion of Thought Broadcasting

In this delusion, the person believes that others can hear their thoughts. This is not the same as telepathy… the affected individual usually believes that anyone nearby can listen in, rather than targeting their thoughts to a specific individual. Thought broadcasting is a symptom of Schizophrenia.

Example: Julie began avoiding her friends because she was sure they could read her mind, especially when she thought about something embarrassing.

  1. Delusions of Thought Insertion

In this type of delusion, the affected person believes that the thoughts in their head are not their own. The thoughts may feel foreign or unusual as if someone or something else is inserting thoughts into their head. The person under the delusion may not know where the thoughts are coming from. This is a symptom of psychosis, which is found in many mental illnesses.

Example from Psych Central: John has been finding himself thinking of highly offensive comments about women that he would never say out loud. He is convinced that his cell phone is somehow implanting these thoughts in his mind.

  1. Delusions of Thought Withdrawl

As it sounds, in this sort of delusion the affected person believes that thoughts have been removed from their mind. This is thought to happen against the patient’s will, and they are powerless to stop it. The patient may be paranoid that breaks in their thoughts or lapses in memory are the result of an outside agency, whether it be a person or an organization, stealing their thoughts. This is considered a positive sign for Schizophrenia.

Example from Psych Central: The man continually blames his poor memory on “government agents” who he claims are able to steal his thoughts.


Delusions and delusion disorders are relatively rare. Doctors always have to consider all the factors that could contribute to delusions, which includes medical problems, neurological issues, mental illness, and substance abuse. Diagnosis is further complicated because delusional individuals tend to hide their delusions.

Diagnosis is usually made by a general medical evaluation and psychological screening. When a medical or neurological problem is suspected, tests such as an electroencephalogram (EEG), magnetic resonance imaging (MRI) or computed tomography (CT) scans may be suggested.

Expected Duration

There is great variation in the duration of this illness. For some, the delusions will only last a few weeks to months. For others, the delusions are persistent over time and may fluctuate in their intensity.


There is no known way to prevent this disorder.


Treatment for this delusional disorders is very challenging, especially if the delusion is long lasting. Antipsychotic medications are most often prescribed, but some delusions do not respond to treatment. Additionally, since patients may not believe they have a mental illness, they may reject all treatment attempts. If the person is willing to meet with a therapist, the support and reassurance of family and friends can be very valuable as the difference between symptoms and reality are repeatedly revealed. The assistance and support from family members, in general, is often the only treatment delusional patients will accept.


 Most people with delusions are able to function quite normally in many areas of their life. Some need limited assistance but are still able to function. Because of this, the outlook varies considerably. For short term delusions, the prognosis is excellent. For the long term, persistent delusions, the outlook is less positive. Any refusal to accept treatment makes the prognosis worse.


Kiran C, Chaudhury S. Understanding delusions. Ind Psychiatry J 2009;18:3-18

sarah4Sarah Emmerling is a scientist, wife, mother, and writer.  She’s been happily married for 10 years and keeps busy with two children and an aging black lab.  She maintains a colorful flower garden, loves to fish, hates to cook, and plays the trumpet in her spare time.  Sarah is an avid sci-fi reader and has an uncanny knack for repairing children’s toys.  She has worked in cancer research for the last 12 years, and has a passion for interpreting science to make it understandable and relatable to the average person.  Sarah has also struggled with treatment-resistant depression since she was 12, and is now diagnosed with Bipolar Disorder, Anxiety, and Attention-Deficit Disorder.  She writes both as a therapeutic outlet and to raise awareness about Bipolar Disorder and mental illness.

You can follow Sarah on Facebook, Twitter, Pinterest and her personal blog.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s