What Causes Hallucinations?

What Causes Hallucinations? The reasons are numerous! Actually, hallucinations happen for reasons more common than you think!


It’s a common misconception to think that having hallucinations means that one is mentally ill or “going crazy.” Causes of hallucinations are far more common than most people believe. They can be caused by medical conditions other than mental illness, dehydration, lack of sleep or bad reactions to new medications or herbs.

Even if a child or loved one with hallucinations is diagnosed with having one or more mental illnesses, the situation is not hopeless. Many people with mental illnesses like psychotic depression, bipolar disorder or schizophrenia can find relief from their symptoms, such as hallucinations, through medications and talk therapy. The prognosis for treating hallucinations caused by mental illness is good.

What are Hallucinations?

What are Hallucinations

Hallucinations happen when one or more senses misfires and make a person believe something is there when it is not. This false information from the senses makes it very difficult (and sometimes impossible) for a person to figure out reality. It’s nearly impossible for a person to ignore hallucinations because they seem identical to reality.

Scientists are not exactly sure what causes hallucinations in some people and not others. Although some direct triggers for hallucinations can be made, such as not sleeping for days, neurologists are still unsure of the exact process the brain or nervous system misfires and send wrong information to the body.

Types of Hallucinations

The most common type of hallucinations is seeing things that are not there and hearing things that are not there. However, one can also smell things that are not there and feel things that are not there. According to a neurologist and best-selling author Oliver Sacks in his book Hallucinations (Vintage; 2012), the rarest type of hallucinations are those of phantom tastes.

Hallucinations range from just annoying to incapacitating. No matter how severe hallucinations are, they should be checked out by a qualified medical professional. This way, Who can rule out serious issues like brain tumours.

Migraine Auras

According to the American Headache Society, one-quarter of all people with migraines (called migraineurs) experience hallucinations called auras. These can overlap or interfere with vision but do not completely cover up the real world. Learning to recognize auras helps migraineurs know when to take medication to prevent migraines’ severe pain. Signs of auras include:

  • Flashing lights
  • Every object has halos
  • Zigzag patterns
  • Sudden loss of vision is usually one (but sometimes both) eyes
  • Hearing strange sounds
  • Felt bizarre tingling on one side of my face.

Not All Hallucinations are Bad

Some hallucinations can be beneficial. For example, many people report seeing and talking to their loved ones soon after they die. Since there is no proof yet of life after death, these “visitations” are hallucinations brought on by grief. People who claim to be visited by their dead loved ones tend to feel much better after the hallucination.

Oliver Sacks mentions a curious case in his book Hallucinations. One of his patients suddenly lost his sense of smell after an operation. After a couple of years, the patient began smelling his favourite coffee in the morning while making coffee. His brain seemed to be giving him memories of coffee’s smell to help him feel better.

Hallucinatory Drugs

The allure of hallucinatory drugs like LSD, mescaline or “magic mushrooms” is powerful. The hallucinations produced often give the user a sense of happiness, well-being and power. This is why our ancestors took hallucinogens. They thought these drugs were a way to communicate with the gods. The hallucinations go away as soon as the drug wears off.

However, there are legal drugs that can cause hallucinations. One is datura or jimson weed, legal in many countries and American states. Painkillers, sleeping pills and psychiatric medications can sometimes cause hallucinations in some people. It is unknown why some people get hallucinations from these drugs, not others. People are most likely to experience hallucinations when taking a drug for the first time.

Medical Conditions

What causes hallucinations for a majority of people are serious medical conditions. The body is fighting to survive and cannot seem to help to misfire in the senses. The only way to treat the hallucinations is to treat the medical condition. If taking care of someone who starts having hallucinations, contact a doctor immediately.

According to the National Institutes of Health, common medical conditions that cause hallucinations include:

  • High fevers
  • Extreme dehydration
  • Temporal lobe epilepsy (it’s thought that Vincent Van Gogh suffered from this)
  • Severe insomnia
  • Damage to the eardrum or ears (which causes aural hallucinations)
  • Narcolepsy
  • Low blood sugar
  • Low blood sodium
  • Terminal illness like cancer or liver failure
  • Dementia in the elderly
  • Drinking a huge amount of alcohol (can make the drinker dehydrated)
  • A combination of the above

It’s especially important for anyone that suspects they are hallucinating not to drive or operate heavy machinery.

How Do You Know If You’re Having An Hallucination?

It is very difficult to tell when you are having a hallucination because it seems to be so real. Some visual hallucinations are easy to spot because they show things, such as inch-tall leprechauns that everyone knows do not exist. Visual hallucinations are particularly hard to disprove yourself. You have to rely on others to tell you whether or not you are hallucinating.

If you are prone to hallucinations, you can learn to distinguish them from the real world through familiarity with them. For example, migraineurs who first experience an aura tend to panic. After experiencing a few migraines, they can then learn to recognize the aura. Talking to other migraineurs with auras can help a migraineur learn to cope.

Hearing Voices

One of the most alarming hallucinations is that of hearing voices. Be careful who you tell and how you describe your voices because this symptom greatly alarms doctors and mental health professionals. For example, hearing your name called as you drift off to sleep is not hearing voices. That is a common auditory hallucination and no signs of severe mental illness.

However, if the voices sound as if a radio is constantly on that you cannot switch off, then the problem should be considered serious. Listen to the content of the voices. If they tell you to harm yourself or others, you need to get help immediately. These voices are lying. If the words of songs are rather benign, this could be a sign of physical illness rather than mental illness. It still should be checked out.

How Bad Can Hallucinations Get?

Hallucinations can get incredibly bad, not just for the person suffering from them but for anyone around them. It is as if the person has been dropped into a nightmare invisible to others. People have been known to attack loved ones because they are convinced that they attack monsters.

People who are hallucinating and begin to become violent need immediate hospitalization. This is not the time to start wondering what the neighbors will say if they know your child has been sent to a mental health facility. People with schizophrenia, for example, tend to suffer periodically from hallucinations. However, the vast majority of people with schizophrenia are harmless to others.

Phantom Limbs

Another common hallucination is known as phantom limb syndrome. This happens to amputees and even people who have lost a finger or a toe. They still feel as if their missing body part is still there. Sometimes they will even feel pain in the missing body part. This is not a sign of mental illness but should be discussed with a medical professional.

Adults are more prone to feeling phantom limb pain than children, notes the New York University Langone Medical Center. Just why this happens is unknown. Phantom limb pain often goes away by itself over time. Even though the limb is missing, this is a real pain, so do not dismiss a person’s pain as “all in your head.”

Imaginary Friends and Highly Creative People

Parents can often become alarmed when their children say they have a friend that no one else can see or hear. Imaginary friends are normal for children of all ages. As long as the imaginary friend does not interfere with real life, such as schoolwork, there is no cause for alarm. Imaginary friends can be very comforting, especially if a child has to move homes or find it difficult to make real friends.

Creative people like painters, composers, mathematicians and writers often state that they see their works in front of them or hear music or voices that are not there. Again, this is nothing to be alarmed about, as long as these images and sounds do not make life impossible for the creative person. Novelists, for example, often hear their characters speaking to them. However, these voices tend to go away at will.

Are You Having a Stroke?

If you or a loved one is suffering from a hallucinatory episode for the first time, doctors and medical personnel may test that person for stroke. This is because strokes can sometimes cause bizarre symptoms, such as visual disturbances, ringing in the ears, or feeling tingles down one side of the body. If the doctor wants to test for stroke, let the doctor do so!