Delusions are a type of abnormal thought content that involve false beliefs that are firmly held despite evidence to the contrary. They are idiosyncratic and can’t be accounted for by a person’s culture, religion, or level of education. They’re considered a type of psychotic symptom, which can occur in the context of various illnesses, including schizophrenia, schizoaffective disorder, delusional disorder, bipolar disorder, and major depressive disorder. While certain themes may be more common in certain disorders, simply knowing the content of someone’s delusional beliefs isn’t enough to determine what their diagnosis is.
We probably all believe things that are false, and we may be quite attached to those beliefs, but these are based in our understanding (however flawed) of reality, whereas delusions represent a greater disconnect from reality. “Normal” flawed ideas may come from believing information from unreliable outside sources, but psychosis is an inside-the-head process. While conspiracy theories, for example, tend to be shared by groups of people, shared delusional beliefs (as occurs in folie à deux) are quite rare. The journal article Understanding Delusions explores different theoretical perspectives on what constitutes a delusion.
Delusions are loosely categorized as being bizarre (e.g. aliens sneaking into your house through the phone line and stealing your organs while you’re sleeping) or non-bizarre (things that are within the realm of possibility but not actually happening, like your neighbour setting up cameras inside your house). In the context of mood episodes, delusions may be categorized as mood-congruent or mood-incongruent.
People who experience hallucinations, which are perceptual disturbances in any of the five senses, may have delusional beliefs associated with those hallucinations, but not all people with delusions have hallucinations, and vice versa.
Sometimes, delusions are systematized, with delusional ideas built on top of one another to form a coherent, organized, and sometimes very elaborate belief system.
Common delusional themes
Persecutory delusions can involve the belief that one is being followed, spied upon, harassed, ridiculed, sabotaged, or poisoned, or that others are harming or attempting to harm the self in some other way. This is a common theme for delusions.
Religion is another common theme, and these kinds of delusions can occur whether people are or are not religious when they’re well. Delusional religiosity is a different creature than the view that some people have that religion in general is a delusion. Delusions deviate from beliefs and experiences that are framed as normal within one’s culture or faith system. Someone who’s experiencing religious delusions might believe that they are God, they are Jesus, they have special powers granted to them by God, or they have special knowledge that’s been imparted to them by God, angels, or other religious figures. These beliefs are not present when they’re well.
Katie R. Dale’s book But Deliver Me From Crazy is a good example of someone who has strong religious faith at baseline, but also experiences religious delusions in the context of manic psychosis, and these deviate from her normal beliefs.
An ex-boyfriend of mine had schizophrenia, and he had recurring religious delusions that involved belief about a special connection to Jesus and knowledge about things contained in the bible. When he was particularly unwell, he would write a lot about this (as in pages and pages for hours). Jesus as the lamb came up a lot, but overall, it didn’t make any sense, and I was never clear on exactly what it was that he believed. When he was doing well, he wasn’t religious.
While the phrase “delusions of grandeur” is sometimes used colloquially to describe people’s overestimation of their abilities, grandiose delusions are a marked departure from reality. This theme is common among people who experience psychosis as part of bipolar mania.
Grandiose delusions have a different flavour to them than narcissism. While excessive pride might mean someone consistently believes they’re such an amazing developer that they’re someone who can make the Metaverse really happen, delusions of grandeur could involve someone with no background in computing believing out of nowhere that they gave Mark Zuckerberg the idea for the Metaverse and have been a key technical advisor every step of the way.
Delusions of control refer to beliefs about outside influences controlling one’s thoughts. These can involve thought insertion (the belief that thoughts are being put into one’s head), thought withdrawal (the belief that thoughts are being taken out of one’s head), or thought broadcasting (the belief that one’s thoughts are being broadcast to others). People may or may not have a sense of where this outside control seems to be coming from.
I experienced thought insertion at one point where it felt like rules were put in my head (not from an identifiable source) for things I had to do.
Delusions of reference
Delusions of reference involve things in the environment having special meanings or messages directed towards the self. Examples include believing that someone on tv is sending coded messages to you through what they’re saying, or believing that items you see when you’re out for a walk have been placed there especially for you.
I’ve had delusions of reference before, and it’s creepy.
Somatic delusions involve things that are going on with the body. This can involve things that are happening inside the body or on the outside of the body. This is different from health anxiety, which involves anxious concerns about things that might be happening; rather, it’s a certainty that things are happening. There may be anxiety that arises from that certainty, but anxiety is not the core issue.
Delusional parasitosis is the term for beliefs about things like critters burrowing into the skin; this may be accompanied by tactile hallucinations.
Delusional jealousy is the idea that one’s partner is cheating kicked up to an extreme level.
Like delusional jealousy, delusional guilt takes a normal experience to extremes. This delusional theme is common in psychotic depression.
I’ve apparently had this before, although I don’t remember it. It doesn’t surprise me, though, as guilt can get pretty intense when I’m not decntly medicated.
Erotomanic delusions involve the belief that another person, often someone famous, is in love with oneself. Acting on them can produce stalker-ish behaviour.
Rarer delusional themes
These involve the belief that familiar people have been replaced by imposters.
These involve the belief that unfamiliar people are actually familiar people in disguise.
These involve beliefs about the self or parts of the self not being real. People with Cotard delusions believe that they’re already dead.
Delusions usually aren’t fun (although occasionally people do have delusions they experience in a positive way), but I find them quite fascinating. The border between “normal” skewed reality and psychotic disconnect from reality can be a blurry one sometimes, but when people are really ill, it can be quite clear to observers that reality has left the building entirely. When I was a nurse, the patient population I most enjoyed working with was people experiencing psychosis, because I just find it so interesting how the psychotic mind works.
If you’ve experienced delusional thinking before, which of these themes have your delusions tended towards?
You may also be interested in theses posts: