Hallucinations: Types, Symptoms and Causes

Hallucinations: Types, Symptoms and Causes

What are Hallucinations?

Common people often use these terms – hallucinations, illusions and delusions – interchangeably. The reality is that these terms mean very different things and it is important to establish a clear difference between them.

Hallucinations are false perceptions of things, voices, images or sensations that occur when there are no external stimuli available. Delusions are false beliefs that are inconsistent with their surroundings. These beliefs are out of touch with reality and even though they are contrary to any logical reasoning, the beliefs are strongly held. Unlike hallucinations, illusions occur when there are external stimuli present. However, they are more related to the misconception and misinterpretation of the stimuli.

Read more; Schizophrenia: What it is, Symptoms and Treatment


  1. Auditory Hallucinations: Auditory Hallucinations are some of the most common types of hallucinations. They involve hearing things that are not really present. They might even engage in the voices they hear. The voices can be in the form of a conversation, critique or even in the form of a command.
  2. Visual Hallucinations: Hallucinations that involve seeing things that are not really present. They can involve setting small things like sudden flashes of light or a person to a more detailed one like a detailed scene.
  3. Tactile Hallucinations: These involve having a false perception that something is touching your skin. These false sensations can involve someone applying pressure, a sense of an insect crawling or even a sensation of burning.
  4. Olfactory Hallucinations: Olfactory means the sense of smell. In olfactory hallucinations, an individual may perceive to be smelling something not really there. It is a less common form of olfactory hallucination.
  5. Gustatory Hallucinations: This form of hallucination is rare and involves perceiving to have a taste in the mouth. Physically there is nothing around them that can cause this taste to be there.
  6. Proprioceptive Hallucinations: Proprioception means having a sense and understanding of how you move and the position of the body. People with proprioceptive hallucinations have a distorted sense of body movement and position. They might feel like their limbs and body parts are in a different position than they are.

Hallucinations can be a symptom of psychosis and psychological disorders like schizophrenia and even neurological disorders. Some individuals also have a specific timing of when they experience hallucinations — either the day or the night. There are names for such hallucinations too. If an individual experiences hallucinations in the morning it is called Hypnopompic hallucinations. Hallucinations that take place at night when you’re about to sleep are called Hypnagogic hallucinations.


The symptoms of hallucinations depend on the type of hallucinations an individual is experiencing. Some of the most common symptoms include —

  • Sensations that something is crawling on the skin when there is nothing present.
  • Feeling that there is a sensation or pressure on the skin without the presence of any external stimuli.
  • Seeing people, images or even flashes of light without any external stimuli.
  • Visual Distortions and Illusions
  • Sense of smell or smelling an odour not really present in the surroundings.
  • Hearing voices, commands or instructions, or sometimes even acting on those commands, that are not really present in the surroundings.
  • Experiencing taste in the mouth that is not present in the surroundings.
  • False perception of being in a scene or elaborately detailed environment.
  • perceiving scents that others cannot detect.

It is usually seen that people do not report their symptoms of hallucinations easily. Therefore, the accurate statistics of assessing how widespread hallucinations are becomes difficult. Visual hallucinations have been reported in 16%–72% of patients with psychotic disorders (Allen et. al., 2023). Hallucinations and delusions are commonly seen with the psychological disorder of schizophrenia. It can also occur due to the use of certain medications. It is sometimes also an occurrence when an individual goes through bipolar disorder.


  • Occurs with schizophrenia.
  • In Bipolar I, hallucinations can occur alongside a manic episode and a depressive episode. In Bipolar II, It mostly occurs with a depressive episode.
  • Alzheimer’s disease.
  • Use of Alcohol or other substances like drugs like marijuana, LSD and cocaine.
  • Withdrawal from substances like drugs and alcohol.
  • Epilepsy
  • Use of Hallucinogens
  • Parkinson’s disease
  • Narcolepsy

A neurocognitive model called the VOICE model has proposed that an unbalanced limbic system mismatched against a hypoactive prefrontal inhibitory system is at play for bringing the cause of hallucinations (Thakur & Gupta, 2022). The limbic system is the part of the brain that processes information, emotions and other functions like hunger and memory. When this part of the brain becomes hyperactive and the prefrontal area cannot inhibit these activities, then there is a high chance of experiencing it.

Read more article from Psychologs

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