Delusions or Hallucinations

Delusions vs hallucinations: the difference

Common types of delusions:

• Persecutory: being followed, spied on, poisoned or plotted against. The most common type. See paranoia.
• Referential: believing TV, songs or strangers carry personal messages.
• Grandiose: having special powers, wealth or a mission.
• Somatic: false beliefs about the body, such as being infested by parasites.
• Jealous or erotomanic: a partner is unfaithful, or someone famous is in love with you.

Types of hallucinations:

• Auditory (voices or sounds): most typical in schizophrenia.
• Visual (people, animals, shapes): more typical of delirium, drugs, dementia with Lewy bodies, Parkinson's disease and eye disease.
• Tactile (bugs crawling on the skin): common with alcohol withdrawal and stimulants.
• Olfactory and gustatory (smells and tastes): can occur with temporal lobe seizures.

What causes delusions and hallucinations

Mental health conditions

• Schizophrenia: hallucinations and delusions for at least 6 months, often with disorganized thinking and withdrawal. It usually starts in the late teens to early 30s.
• Bipolar disorder: grandiose delusions during mania, or guilt-laden delusions in severe depression.
• Severe depression with psychotic features.
• Delusional disorder: a single, fixed delusion with otherwise normal functioning.
• Brief psychotic disorder, often after extreme stress.
• Postpartum psychosis: a psychiatric emergency in the first weeks after childbirth.
• PTSD can cause flashbacks with vivid sensory experiences, which are different from psychosis.

Substances

• Cannabis, especially high-potency forms, and synthetic cannabinoids
• Stimulants: methamphetamine and cocaine
• Hallucinogens: LSD, psilocybin, PCP and ketamine
• Withdrawal from alcohol or benzodiazepines, which can progress to delirium tremens

Symptoms that persist after the drug wears off are called substance-induced psychosis.

Medical and neurological causes

• Delirium: sudden confusion with visual hallucinations from infection, dehydration, medicines or surgery, especially in older adults
• Dementia: particularly Lewy body dementia, where vivid visual hallucinations are an early feature
• Parkinson's disease and its medicines
• Epilepsy, especially temporal lobe seizures
• Brain tumors, stroke and brain infections such as encephalitis
• Hormone and metabolic problems: thyroid disease, very low sodium or blood sugar, liver or kidney failure
• Severe sleep deprivation and narcolepsy
• Vision loss: Charles Bonnet syndrome causes vivid, silent visual hallucinations in people with poor sight who know the images are not real
• Medicines: steroids, some Parkinson's drugs, anticholinergics and high doses of some sedatives

Early warning signs of psychosis

A first episode often follows a period of subtle change lasting weeks to months:

• withdrawing from friends and family
• falling performance at school or work
• suspiciousness or unusual ideas
• trouble concentrating or thinking clearly
• sleep problems
• strong, inappropriate emotions or little emotion at all
• neglecting self-care

How doctors assess delusions and hallucinations

1. History from the person and, with permission, family: onset, substances, medicines, sleep, mood, stress and family history.
2. Mental state examination to explore the beliefs and experiences and to assess risk.
3. Physical examination, including neurological checks.
4. Tests to rule out medical causes: blood count, sodium, glucose, kidney, liver and thyroid function, drug screen, and sometimes HIV and syphilis tests.
5. Brain imaging (MRI or CT) or an EEG if there are neurological signs or the picture is atypical.

Treatment

• Treating the cause: infection, delirium triggers, metabolic problems or stopping a culprit drug or medicine.
• Antipsychotic medicines reduce hallucinations and delusions in schizophrenia, bipolar disorder and other psychotic disorders. The choice balances benefits and side effects such as weight gain and stiffness.
• Coordinated specialty care for a first episode: early intervention teams combine medicine, therapy, family support, and education and employment help.
• Cognitive behavioral therapy for psychosis (CBTp) helps people cope with voices and distressing beliefs.
• Mood stabilizers or antidepressants when psychosis is part of a mood disorder.
• In dementia and Parkinson's, treatment is cautious. Some antipsychotics can cause serious reactions in Lewy body dementia, so specialists choose medicines carefully.

How to support someone experiencing psychosis

• Stay calm and speak simply.
• Do not argue about the delusion or pretend to agree. Acknowledge their feelings ("That sounds frightening").
• Reduce noise and stimulation.
• Encourage them to see a doctor, and offer to go with them.
• If there is any risk of harm, call 988 or emergency services.

Frequently asked questions

What is the difference between delusions and hallucinations?

A delusion is a false belief, such as being certain you are being watched, that does not change with evidence. A hallucination is a false sensory experience, such as hearing a voice or seeing a person who is not there. Both can occur in psychosis, but they can also occur separately.

Can stress cause hallucinations?

Extreme stress, trauma and severe sleep deprivation can trigger brief hallucinations or a short psychotic episode in some people. Grief can also bring brief experiences of hearing or seeing a loved one, which are common and not a sign of illness. Persistent or distressing symptoms need assessment.

Is it normal to hear things when falling asleep?

Yes. Brief sounds, voices or images while falling asleep (hypnagogic) or waking (hypnopompic) are common and usually harmless. They are more frequent with sleep deprivation and narcolepsy. Experiences that happen while fully awake or cause distress should be discussed with a doctor.

Can delusions and hallucinations be cured?

Many causes are treatable. Hallucinations from delirium, drugs or medicines usually stop when the cause is addressed. With early treatment, many people recover from a first psychotic episode. Schizophrenia is usually long-term, but medicine and support allow many people to live well.

Can older adults suddenly start hallucinating?

Yes. Sudden hallucinations in older adults are most often due to delirium from an infection, dehydration or a new medicine, and need same-day medical review. Gradual hallucinations can point to Lewy body dementia, Parkinson's disease or vision loss (Charles Bonnet syndrome).