Hallucination is a sensory experience of something that does not exist outside the mind.
Hallucinations can affect any senses (vision, hearing, smell, taste, and tactile feelings) and bodily sensations. It is a false perception that may seem very real to the person who is hallucinating. Visual and auditory hallucinations are the most common types of hallucinations.
For example, a person might see someone or something that is not actually present or hear voices that do not actually exist. There are five types of hallucinations, categorized by which of the five senses they affect:
• When someone experiences hearing something in the absence of actual stimulus, it is an Auditory hallucination. This is the most common type of hallucination in schizophrenia and other forms of psychosis. Auditory hallucinations could be verbal when a person hears someone is speaking to him/her or simple sounds when a person hears noises such as a door or floor squeaking, steps, etc;
• Visual hallucination include shadows, flashes of light, or insects. It occurs when an individual sees something that is not really there.
• Tactile hallucinations are those that affect a person’s sense of touch. Feeling something crawling on the skin, when nothing is actually there, is an example of a tactile hallucination. It is when people feel touch or movement on part of their body.
• Olfactory hallucination affects an individual’s sense of smell. An individual having an olfactory hallucination may experience the smell as coming from their environment or from their own body.
• Gustatory hallucinations affect the sense of taste. A person who has gustatory hallucinations may experience an odd taste from the things they eat or drink, or they may notice a taste in the absence of an actual stimulus.
Bodily hallucinations occur when multiple senses and body parts when people are feeling something which is not happening to them but appears as real. An example of bodily hallucinations is sexual hallucinations in patients after anesthesia or in elderly socially isolated people.
A few hundred years ago hallucinations might have been ascribed to the influence of Gods or ghosts. Nowadays, neuroscientists and psychologists see hallucinations as a result of abnormal activity in the brain. When you look at something in the outside world, your brain doesn’t magically ‘reach out and touch’ the object so you can perceive it. Instead, the brain builds a model of what is probably out there in the world, doing its best to match the model to the sensory input we receive at our sense organs (for example, in the retina of the eye). The things you perceive reflect the model the brain builds – a model built out of the buzzing activity of billions of neurons in your brain. It’s basically intelligent guesswork, but mostly our brains do pretty well, and we have the impression of a stable world. Importantly, we tend to agree with other people about what’s out there – which gives an indication that our brains are getting things right! However, if the activity of the brain is in some way altered by a neurological disturbance of one form or another, the model can diverge from its normal faithful representation of the outside world, and we can have hallucinatory perceptions.
The total idea of Hallucination is totally based on what our body perceives or forms a perception about which can be caused by various reasons and disorders such as mental illness, the side effects of medications, physical illnesses like epilepsy or alcoholism, anesthesia, substance and alcohol abuse, prolonged sleep deprivation, terminal illnesses, such as brain cancer, kidney, and liver failure, or AIDS, high fevers, migraine headaches, social isolation, seizures, deafness, blindness, vision problems, stress, bereavement, depression, and dementia. There are multiple findings reported, often conflicting, and not clearly explained. The hypothesis gives a more cohesive view of the nature of hallucinations bringing together morphological, neuronal, and phenomenal concepts. It still needs to be clearly proven experimentally. This whole area of research is very exciting but still remains in infancy.
Here, we highly recommend you go to a doctor if you are facing any of such things, this article is only for information purposes but not for self-cure!