Hallucinations refer to the experience of sensing things that exist only in your mind. During a hallucination, you may see, hear, feel, smell, or taste things that are not there—that is, they have no external source.
There are many possible causes for hallucinations, including mental health disorders, physical conditions, sensory problems, and drug use or withdrawal. Learn more about hallucinations, including symptoms, types, causes, treatment, and when to seek help.
Symptoms of Hallucinations
Hallucinations involve problems with sensory perception—that is, the five senses. You might be experiencing a hallucination if you are seeing, hearing, touching, tasting, or smelling things that are not there. They may feel real, but they exist only in your mind.
Other signs that you or someone you know is having a hallucination may include:
- Behaving in a way that isn’t appropriate for the situation
- Appearing to be responding to stimuli that aren’t present
- Being oddly distracted
How Common Are Hallucinations?
Hallucinations are more common than you may think. One study in JAMA Psychiatry revealed that about 1 in 20 people in the general population had experienced at least one hallucination in their life.
Types of Hallucinations
There are five major types of hallucinations. Each one of them involves one of the five senses, including:
- Auditory: Auditory hallucinations involve hearing voices and/or sounds that aren’t there. These voices or sounds may be harmless. You might hear music, laughing, doors banging, or footsteps. They may also include command hallucinations—voices instructing you to do something, whether positive and innocuous (such as wearing a certain outfit) or dangerous (such as harming yourself or others).
- Visual: People with visual hallucinations see things that aren’t there, such as lights, patterns, items, shapes, colors, or people.
- Tactile: Tactile hallucinations involve feeling sensations, such as something crawling beneath your skin, that have no origin.
- Olfactory: People with olfactory hallucinations smell odors with no real source.
- Gustatory: Gustatory hallucinations cause you to taste something that isn’t there.
Auditory and visual hallucinations are the two most common types of hallucinations. Gustatory hallucinations are very rare.
Causes of Hallucinations
Many people associate hallucinations only with mental health disorders. However, there are many other possible reasons that someone may have a hallucination – including neurological disorders, substance use and withdrawal, sensory conditions, and more.
Mental Health Conditions
Along with delusions (false, fixed personal beliefs), hallucinations are part of psychosis—a mental state that causes someone to lose touch with reality.
People with psychotic disorders (mental disorders that cause abnormal thinking, speech, and/or perceptions) and certain other mental health disorders are more likely to have hallucinations. Mental health conditions that may cause hallucinations include:
- Schizophrenia: Up to 75% of people with schizophrenia—a brain disorder that causes disturbances in thinking, emotions, and functioning—experience hallucinations. These are usually auditory hallucinations that involve hearing voices.
- Bipolar disorder: Bipolar disorder is a mood disorder that causes elevations in mood or energy and often involves major depressive episodes. Many estimates suggest that around half of people with bipolar disorder psychotic symptoms, including hallucinations.
- Schizoaffective disorder: People with schizoaffective disorder experience both symptoms of schizophrenia, including hallucinations and delusions, and symptoms of a mood disorder (such as bipolar disorder).
- Post-traumatic stress disorder (PTSD): Some people with PTSD experience hallucinations, especially while having flashbacks to traumatic memories or during times of stress.
- Depression: Some people with severe major depressive disorder (MDD) also have hallucinations and/or delusions. In many cases, their hallucinations are related to depressive themes of worthlessness, inadequacy, or guilt.
Sometimes, hallucinations are caused by a neurological condition—a medical condition that affects the brain and nervous system. Brain and nervous system conditions that may alter sensory perception include:
- Dementia: Many people with dementia, including Alzheimer’s disease, have hallucinations and/or delusions, especially during the later stages of the disease.
- Delirium: Delirium refers to a mental state of confusion that often occurs in older adults due to a medical issue causing brain toxicity. Symptoms include disorientation and hallucinations, among others.
- Epilepsy: Epilepsy is a brain disorder that causes seizures. Certain types of epilepsy cause hallucinations.
- Narcolepsy: Narcolepsy is a sleep disorder that causes excessive daytime sleepiness and episodes during which someone suddenly falls asleep at inappropriate times. People with narcolepsy may experience hallucinations, usually while falling asleep or just waking up.
- Parkinson’s disease: Parkinson’s disease is a brain disorder that causes symptoms like difficulty walking and talking, muscle stiffness, tremor, and ultimately memory problems. About 20% to 30% of people with Parkinson’s experience hallucinations, sometimes as a side effect of medication.
- Brain cancer: Depending on the part of the brain that is affected, people with brain injuries, tumors, and/or cancer may experience hallucinations.
Substance Use and Withdrawal
The following psychoactive substances (substances that alter the way the brain works) may cause hallucinations:
- Hallucinogens, such as d-lysergic acid diethylamide (LSD), cannabis, ketamine, psilocybin (mushrooms), and phencyclidine (PCP)
- Sometimes opiates, alcohol, and amphetamines
Hallucinations may occur while someone is intoxicated (drunk or high) or when they are in withdrawal after taking certain substances regularly.
Many medical conditions that affect the senses, such as the ability to see or hear, can cause hallucinations. Some examples include:
- Charles Bonnet syndrome (CBS), a disorder that causes visual hallucinations after someone loses some or all of their vision
- Vision loss or blindness
- Hearing loss or deafness
Other medical causes for hallucinations may include:
Sometimes, hallucinations are not related to any medical condition or problem. You may be more at risk of hallucinating if you are:
- Grieving, especially if you think you see or hear your lost loved one
How to Treat Hallucinations
Treatment options for hallucinations typically include psychotherapy and antipsychotic medication.
Psychotherapy, such as cognitive behavioral therapy (CBT) may help change the way someone responds to and thinks about their hallucinations. If hallucinations are related to a history of trauma or abuse, trauma-informed therapy may help.
Antipsychotic medications, such as Risperdal (risperidone) and Seroquel (quetiapine), may be prescribed to treat symptoms of psychosis associated with schizophrenia, bipolar disorder, and other psychiatric and neurological conditions.
The Food and Drug Administration (FDA) has approved Nuplazid (pimavanserin) to treat hallucinations in patients with Parkinson’s disease.
In many cases, treating the underlying medical cause for your hallucinations will improve or eliminate the hallucinations.
Are There Tests to Diagnose the Cause of Hallucinations?
If you think you’re having hallucinations, your healthcare provider can start the process of diagnosis by gathering important information about your symptoms, medical history, and drug and alcohol use.
From there, they may perform an evaluation to rule out potential medical contributions to your symptoms, including a physical exam, blood or urine tests, and diagnostic imaging (such as a brain scan).
You may have to see a specialist, such as a psychiatrist or neurologist for further assessment and treatment.
When to See a Healthcare Provider
If you think you may be having hallucinations, seek immediate medical help. Hallucinations could be a sign of an underlying mental illness or another serious medical condition. It’s important to seek a diagnosis so you can begin appropriate treatment.
If someone you know seems to be confused, disoriented, speaking incoherently, or losing touch with reality, it’s important not to leave them alone. Talk to a healthcare provider or go to the emergency room right away.
Seek Emergency Help
Call 911 or seek emergency medical help for hallucinations if you:
- Have a seizure
- Are confused
- Are speaking incoherently or not making sense
- Hear voices telling you to harm yourself or others
Hallucinations involve seeing, hearing, feeling, tasting, or smelling things that aren’t really there. In many cases, hallucinations are caused by mental health conditions, such as schizophrenia or bipolar disorder.
They may also be caused by neurological conditions (including Parkinson’s disease, epilepsy, and dementia), vision loss, drug use, or serious illness (such as kidney or liver failure).
Treatment options for hallucinations include psychotherapy, such as cognitive behavioral therapy (CBT), and antipsychotic medication. If the hallucinations are caused by an underlying illness, treating that condition may prevent future hallucinations as well.
A Word From Verywell
While hallucinations may be alarming, they are not uncommon and are often treatable. Don’t be afraid to seek help from your healthcare provider if you think you might be sensing things that aren’t there.
Frequently Asked Questions
What causes hallucinations?
Hallucinations are often caused by mental health conditions, such as psychotic disorders (like schizophrenia) or mood disorders (such as bipolar disorder).
Neurological conditions, such as dementia, delirium, epilepsy, or brain cancer, may also cause hallucinations. In some cases, sensory conditions like Charles Bonnet syndrome may lead to visual hallucinations.
Substance use, fever, migraine, bereavement, and coming out of anesthesia may also cause someone to hallucinate.
What are the types of hallucinations?
There are five types of hallucinations. Each one is related to one of the five senses. These include: auditory hallucinations (hearing voices and other sounds that aren’t there), visual hallucinations (seeing things that aren’t there), tactile hallucinations (having the sensation of someone or something touching you), olfactory hallucinations (smelling odors that aren’t there), and gustatory hallucinations (having a taste in the mouth that has no source).
Are hallucinations and delusions the same thing?
Both hallucinations and delusions fall under the broader category of psychosis—a mental state that involves losing touch with reality. Hallucinations involve problems with sensory perceptions, such as hearing or seeing things that are not there. A delusion is a fixed, false belief that does not change even when someone is presented with evidence that it is not true.