What are delusions?

Delusions are false ideas or beliefs that someone holds onto, even when there is evidence that they are not real. These beliefs are not shared by other people from the same:

• cultural background
• religion
• social group

For example, someone might believe they are the captain of the Australian rugby team, or that an alien has taken over the body of someone in their family.

No facts or reasoning can shake this belief. The delusion seems entirely real, and you (or they) may become completely preoccupied with it.

People with psychosis may have delusions and hallucinations (usually, hearing something that doesn't exist). They may also have other symptoms, such as confusion or memory problems.

Delusions can be confusing and scary.

What are the types of delusions?

There are several different types of delusions.

• Grandiose delusions — when a person believes they are very talented, rich or influential.
• Paranoid delusions — when a person believes others want to harm them or are persecuting them.
• Somatic delusions — when a person believes there is something wrong with a part of their body, or that part of them is missing.
• Bizarre delusions — when a person believes in something that is physically impossible.
• Jealous delusions — when a person believes their partner is being unfaithful, even when that's impossible.
• Erotomanic delusions — when a person believes someone (usually someone of higher social standing) is in love with them.

What causes delusions?

Delusions can be a symptom of some mental illnesses, such as:

• psychosis
• schizophrenia
• a mood disorder such as bipolar disorder or depression
• postpartum psychosis
• a personality disorder

Sometimes symptoms of psychosis (including delusions) can happen with conditions such as:

• dementia
• Parkinson's disease
• traumatic brain injury
• epilepsy
• brain tumour
• delirium

Substance use can also cause delusions. This can include:

• over-the-counter medicines and supplements
• prescription medicines
• illicit drugs
• alcohol

Other causes of psychosis can include:

• exposure to certain chemicals
• autoimmune conditions
• hormonal conditions
• some vitamin deficiencies

How is the cause of delusions diagnosed?

Your doctor will ask about your symptoms and how long you have had them. They will ask about medicines and other substances you have taken. They may also examine you to check your physical health.

Your doctor may recommend some tests to help with diagnosis. These may include:

• blood tests
• urine tests
• a brain scan (CT scan or MRI scan)

When should I see my doctor?

See your doctor as soon as possible if you or someone you care for may be having delusions.

Your doctor may refer you to a mental health professional to help diagnose the cause of the delusions. This may be a psychiatrist (doctor who specialises in mental health conditions).

When to seek urgent care

A crisis assessment and treatment team (CATT) can respond to urgent requests to help people in mental health crisis 24 hours a day, 7 days a week.

How are delusions treated?

Treatment will depend on the cause of your delusions.

Medicines for delusions

Medicines can be used to treat delusions, including:

• antipsychotic medicines
• antidepressants
• mood stabilisers

Other treatment options

Depending on the cause of the delusions, other therapies are also sometimes used. These may include:

• cognitive behaviour therapy
• psychodynamic psychotherapy

Your doctor, psychologist or psychiatrist may be able to help with these treatments.

Community support programs are also available and may be suitable for some people with delusions. These can help with:

• social connection
• your physical health
• accommodation
• work or study

Ask your doctor, social worker or specialist about support programs.

Caring for someone with delusions

If someone you know is having delusions, remember that the delusions may seem very real to that person. You can help by:

• showing them love and support
• helping them to recognise what triggers the delusions
• encouraging them to seek treatment

It's best not to:

• argue with them
• pretend to agree with their delusions
• try to persuade them with evidence
• laugh at them or ridicule them

Make sure you also get support for yourself if you are caring for someone with psychosis.

Resources and support

The following resources can help if you are concerned about delusions.

• For help and support, call Lifeline on 13 11 14.
• Medicare Mental Health — for advice and to get connected to local mental health services, call 1800 595 212. Check the operating times.
• SANE Australia — contact their support line on 1800 187 263.
• Contact the free, confidential National Dementia Helpline on 1800 100 500, any time of the day or night, for information, advice and support.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.