Hallucinations are defined as "an apparent perception of an external object when no such object is present". Hallucinations are false or distorted sensory experiences that appear to be real perceptions. These sensory impressions are generated by the mind rather than by any external stimuli, and may be seen, heard, felt, and even smelled or tasted. The hallucinatory experience has a wide range of etiologies like neurological insult, seizure and sleep disorders, drug reactions, substance abuse, grief, stress, as well as metabolic, endocrine and infectious diseases. Symptom frequently associated to the severity of other mental illnesses.
A hallucination occurs when environmental, emotional, or physical factors such as stress, medication, extreme fatigue, or mental illness cause the mechanism within the brain that helps to distinguish conscious perceptions from internal, memory-based perceptions to misfire. As a result, hallucinations occur during periods of consciousness. They can appear in the form of visions, voices or sounds, tactile feelings, smells, or tastes. Patients suffering from dementia and psychotic disorders such as schizophrenia frequently experience hallucinations. Hallucinations can also occur in patients who are not mentally ill as a result of stress overload or exhaustion, or may be intentionally induced through the use of drugs, meditation, or sensory deprivation.
Prolonged or extreme stress can impede thought-processes and trigger hallucinations. Sleep deprivation and/or exhaustion can lead to hallucinations. Physical and emotional exhaustion can induce hallucinations by blurring the line between sleep and wakefulness. Prominent hallucinations appear in a depression or elation phase, it is also found as a symptom frequently associated to the severity of other mental illnesses.
When the brain lacks external stimulation to form perceptions, it may compensate by referencing the memory and form hallucinatory perceptions. This condition is commonly found in blind and deaf individuals.
Lesions or injuries to the brain may alter brain function and produce hallucinations. Apart Medico-Surgical conditions can produce hallucinations.
Use of Psychotomimetics and Medications side-effects: Hallucinogenics such as ecstasy, LSD, mescaline (3,4,5-trimethoxyphenethylamine, or peyote), and psilocybin trigger hallucinations. Other drugs such as marijuana and PCP have hallucinatory effects. Certain prescription medications may also cause hallucinations. In addition, drug withdrawal may induce tactile and visual hallucinations.
The olfactory hallucinations are associated with aural gustatory hallucinations. Olfactory, or uncinate seizures, are mostly reported as unpleasant odors, such as burning rubber, feces, rotting manure, sulfur, or indescribable. Frequently, The patient may describe elementary tastes like sweet, salty, bitter, or odd flavors.
Occasionally, people who are in good mental health will experience a hallucination. If hallucinations are infrequent and transitory, and can be accounted for by short-term environmental factors such as sleep deprivation or meditation, no treatment may be necessary. However, if hallucinations are hampering an individual's ability to function, a general physician, psychologist, or psychiatrist should be consulted to pinpoint their source and recommend a treatment plan. Hallucinations that are symptomatic of a mental illness such as schizophrenia should be treated by a psychologist or psychiatrist.