Hallucinations

Overview

Hallucinations are sensory experiences that seem real but are created by the mind rather than coming from the outside world. A person may hear voices or sounds, see things that are not there, feel sensations on the skin, or notice smells or tastes with no source. They are a symptom rather than a diagnosis and can arise from mental health conditions, brain disorders, medical illness, medications, or substances.

Hallucinations vary widely, from a brief experience while falling asleep, which is normal, to persistent voices that are distressing or frightening. Because they can be a sign of a serious medical or psychiatric problem, new or worsening hallucinations should be evaluated. When they occur with confusion, fever, or thoughts of harming oneself or others, they require urgent attention.

It is worth knowing that not all hallucinations indicate illness. Brief experiences as you fall asleep or wake, and hallucinations in someone who is grieving, can be entirely normal. The features that matter most are how often they occur, how distressing they are, and whether they come with confusion or other warning signs.

Common Causes

Hallucinations have many possible causes across mental health and medical conditions:

• Psychiatric conditions: Schizophrenia and severe mood disorders such as bipolar disorder can involve hallucinations.
• Delirium: An acute confusional state from infection, medication, or other illness (delirium), common in hospitalized or older people.
• Dementia: Some types of dementia, particularly Lewy body dementia, cause visual hallucinations.
• Substances: Alcohol withdrawal, recreational drugs, and certain medications.
• Neurological conditions: Parkinson disease, seizures, brain tumors, and migraine.
• Sensory or sleep-related causes: Hallucinations while falling asleep or waking, and those linked to vision or hearing loss.

Fever, infection, or sudden onset of hallucinations with confusion points toward a medical emergency such as delirium and needs prompt assessment.

Associated Symptoms

The symptoms accompanying hallucinations help identify the cause:

• Confusion or disorientation
• Delusions or personality changes
• Fever with infection-related delirium
• Memory loss in dementia
• Tremor, agitation, or sweating with substance withdrawal
• Distress, fear, or thoughts of harming oneself or others

Hallucinations with new confusion, fever, or any thoughts of self-harm or harming others are urgent and need immediate help.

The nature of the hallucination can itself be a clue. Voices that comment or command are more typical of psychiatric causes, while vivid visual hallucinations, especially of people or animals, are more often seen in delirium and certain dementias.

Diagnosis & Evaluation

Evaluation aims to find the underlying cause, which guides treatment:

• History: Asking about the type of hallucinations, their onset, medications, substances, and mental health history.
• Physical and mental state exam: Checking for confusion, infection, and other signs.
• Blood and urine tests: Looking for infection, metabolic problems, or substances.
• Brain imaging: CT or MRI when a neurological cause is suspected.
• Specialist assessment: Psychiatric or neurological evaluation depending on the picture.

Treatment & Management

Treatment is directed at the underlying cause:

• Treating medical causes: Addressing infection, correcting metabolic problems, and reviewing medications for delirium.
• Psychiatric treatment: Antipsychotic medicines and therapy for conditions such as schizophrenia, under specialist care.
• Managing substance-related causes: Safe treatment of alcohol or drug withdrawal.
• Dementia care: Tailored approaches for hallucinations in dementia, with cautious use of medication.
• Support and safety: A calm environment and support for the person and family.

Because the right treatment depends entirely on the cause, hallucinations should be assessed by a professional rather than self-managed.

Alongside medical treatment, a calm, familiar, and well-lit environment can reduce fear and confusion, especially for older people and those with dementia. Reducing alcohol and recreational drugs, treating poor sleep, and supporting hearing and vision can also lessen some hallucinations.

When to See a Doctor

See a doctor for any new, persistent, or distressing hallucinations so the cause can be found. Seek emergency care immediately if hallucinations come with:

• Thoughts of harming oneself or others
• New confusion, drowsiness, or disorientation
• Fever, severe headache, or a stiff neck
• Seizures or sudden weakness
• Severe agitation, sweating, and tremor during alcohol or drug withdrawal

If you or someone else is in immediate danger, call emergency services or a crisis line right away.

Related Topics

Frequently Asked Questions

References

1. National Institute of Mental Health (NIMH). Understanding psychosis.
2. Mayo Clinic. Hallucinations and delirium.
3. MedlinePlus, U.S. National Library of Medicine. Hallucinations.
4. National Institute on Aging. Lewy body dementia and hallucinations.