Delusions: when beliefs feel completely real

To the person, a delusion doesn’t feel like a theory. It feels as obvious as the floor under their feet. That’s why arguing rarely helps.

Beliefs that are normal in someone’s religion, culture or community are not delusions. Clinicians are expected to take this into account.

What can stand out is a belief that is new, that the person’s own community doesn’t share, and that causes distress or changes how they live.

Researchers describe “overvalued ideas” as unusual beliefs a person holds strongly, but with at least some doubt. A delusion usually leaves no room for doubt at all. The line between the two can be blurry, which is why only a professional can assess it.

Some people believe an outside force, such as a device, a satellite, or a spiritual being, is controlling their thoughts or actions. Some feel thoughts are being put into or taken out of their mind, or that others can hear their thoughts.

This is the most common theme. A person might believe they are being followed, that their phone is tapped, or that someone is poisoning their food.

In this type, a person is convinced that someone, often of higher status, is in love with them, even without any contact or sign of interest.

Somatic delusions are fixed beliefs about the body and how it works or feels, held firmly despite reassurance.

Beliefs that you are evil, or have committed a sin that can’t be forgiven, are more common during severe depression.

Jealous delusions are fixed beliefs that a partner is cheating. Researchers note they are often linked with heavy alcohol use.

They can also appear in dementia and Parkinson’s, where a person may believe their spouse is having an affair.

Sometimes called ideas of reference. A person may feel the radio, a news story, or a stranger’s gesture carries a message meant only for them.

Nihilistic delusions are beliefs that oneself, others or the world have been destroyed or don’t exist. They always deserve prompt care from a professional.

Called Capgras syndrome, this is a belief that a familiar person has been replaced by a look-alike. It can happen in Lewy body dementia and other conditions.

It can be deeply painful for the family member who isn’t recognised. Remember it is the illness, not a choice.

Grandiose delusions are beliefs of great talent, power, wealth or a special mission, or a link to someone famous or divine. They can appear during mania, as well as in psychosis.

In Lewy body dementia, a person may believe a spouse is having an affair, or that relatives who died long ago are still alive. In Alzheimer’s, a person may believe things have been stolen.

Brain injury can also lead to psychosis and unusual beliefs.

Delirium is sudden confusion, often caused by an infection, especially in older people. It can come with seeing or hearing things and odd beliefs. It needs medical help straight away.

Very low mood can bring beliefs of guilt or ruin. Mania can bring beliefs of special powers or importance. These ease as the mood episode is treated.

Psychosis can include hallucinations, delusions, or both. NIMH gives the example of believing people on TV are sending special messages.

Postpartum psychosis usually starts in the first two weeks after birth. It can bring unusual beliefs, hallucinations, confusion and big mood changes, sometimes shifting hour to hour.

In a review of studies with healthy volunteers, delusions began to appear after about 72 hours awake. Normal sleep resolved the symptoms in many, though not all, cases.

Cannabis, cocaine, amphetamines and other drugs can bring on psychosis. So can withdrawal from alcohol.

Stressful events, such as a close relative dying, and childhood abuse or neglect can make psychosis more likely. It is never the person’s fault.

The Royal College of Psychiatrists notes that delusions can explain hallucinations. Someone who hears voices talking about them might come to believe the neighbours are plotting.

Research on fears of being harmed shows that worry, low self-confidence and poor sleep help these beliefs start and last.

People with fixed beliefs often find it harder to consider other explanations, and may decide faster on less evidence. These are thinking habits, not flaws of character, and talking therapies can work on them.

Delusions can be harder to spot when they link to real things, such as a job with secret information or a past abusive relationship. A real history can make a fear feel even more believable.

You don’t have to agree with the belief to care about how it makes someone feel. Acknowledging the emotion builds trust.

Things you might say

• “I can see you’re worried. Let’s talk to someone who can help.”
• “I don’t see it the same way, but I can tell how real it feels.”
• “It must be frightening to believe that.”
• “That sounds frightening.”

Try not to

• Agree with the belief just to keep the peace, which can make it stronger
• Debate whether it’s true
• Dismiss feelings, such as “That’s ridiculous”
• Laugh at or make fun of the belief

Small things that help

• Keep your voice calm and steady
• Lower the noise and keep few people around
• Sit beside them rather than face-to-face
• Tell them you are on their side

When someone is very unwell, practical help can ease the fear. For example, switching off a TV they feel is talking to them.

You can also suggest a gentle distraction, or agree on limits for how much time you spend talking about the belief.

Encourage them to speak with a mental health professional. Exploring other explanations can come later, and only if and when it feels right.

Consider your own safety as well as theirs. Anger can come from the fear a belief causes, so respond to the fear rather than raising the tension.

If you feel unsafe, leave and get help. In the U.S., call 911 in an emergency.

Writing down when a belief feels stronger, and what was going on, can show links with tiredness, stress or certain places. Poor sleep and worry are known to make fears of harm stronger.

Severe sleep loss can bring unusual beliefs in anyone, and sleep problems are linked to fears of being harmed. Making sleep a priority is a kind thing to do for your mind.

Sharing worries with someone you trust can ease the load. You might agree that they’ll tell you, kindly, if they notice you seem unwell, such as not sleeping or pulling away. These changes can be early warning signs.

You don’t have to agree that anything is “wrong” to see a clinical provider. Many people start by talking about sleep, stress or worry. Talking therapies for psychosis focus on your own goals and how you make sense of experiences, not on arguing.

If an older person suddenly becomes confused, or starts seeing or believing things, delirium is possible. It is often caused by infection and needs urgent medical care.

Families describe

• Believing a family member has been replaced by an impostor
• Believing a spouse is having an affair
• Believing relatives who died are still alive
• Believing things are being stolen or hidden

Tips from dementia experts

• Don’t take accusations personally
• Keep answers short and simple
• Listen to the worry behind the belief
• Keep spares of items that often go “missing”
• Reassure, then switch to a calm activity

Jealous and persecutory beliefs are the most common in Parkinson’s. The Parkinson’s Foundation advises staying calm, not arguing, and telling the care team about every change, even small ones.

Many people first turn to a faith leader when something feels wrong. Leaders who know the basics can listen without judging and gently encourage a health check alongside spiritual support.

Hearing Voices groups offer respectful spaces to talk about voices, visions and other unusual experiences without stigma.

Family programmes run by professionals include learning about the condition, managing stress and solving problems together. The more people understand, the less room there is for fear and stigma.