Hallucination

Hallucination

A hallucination is a perception in the absence of a stimulus

hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli

Hallucinations can occur in any sensory modality — visual, auditory, olfactory, gustatory, tactile, proprioceptive, equilibrioceptive, nociceptive, thermoceptive and chronoceptive.

Classification of hallucinations
Visual , Auditory, Olfactory, Tactile

Stages of a hallucination

1. Emergence of surprising or warded-off memory or fantasy images
2. Frequent reality checks
3. Last vestige of insight as hallucinations become "real"
4. Fantasy and distortion elaborated upon and confused with actual perception
5. Internal-external boundaries destroyed and possible pantheistic experience

Cause

Hypnagogic hallucination
occur just before falling asleep,hallucinations last from seconds to minutes, all the while the subject usually remains aware of the true nature of the images, may be associated with narcolepsy. Hypnagogic hallucinations are sometimes associated with brainstem abnormalities, but this is rare

Peduncular hallucinosis
Peduncular means pertaining to the peduncle, These hallucinations usually occur in the evenings, but not during drowsiness. The subject is usually fully conscious and then can interact with the hallucinatory characters for extended periods of time ,insight into the nature of the images remains intact. The false images can occur in any part of the visual field, and are rarely polymodal

Delirium tremens
One of the more enigmatic forms of visual hallucination is the highly variable, possibly polymodal delirium tremens. Individuals suffering from delirium tremens may be agitated and confused, especially in the later stages of this disease. Insight is gradually reduced with the progression of this disorder. Sleep is disturbed and occurs for a shorter period of time, with rapid eye movement sleep.

Parkinson's disease and Lewy body dementia
Parkinson's disease is linked with Lewy body dementia for their similar hallucinatory symptoms. The symptoms strike during the evening in any part of the visual field, and are rarely polymodal. The segue into hallucination may begin with illusions where sensory perception is greatly distorted, but no novel sensory information is present. These typically last for several minutes, during which time the subject may be either conscious and normal or drowsy/inaccessible. Insight into these hallucinations is usually preserved and REM sleep is usually reduced

Migraine coma
This type of hallucination is usually experienced during the recovery from a comatose state. The hallucinations occur during states of full consciousness, and insight into the hallucinatory nature of the images is preserved

Charles Bonnet syndrome
Charles Bonnet syndrome is the name given to visual hallucinations experienced by blind patients. The hallucinations can usually be dispersed by opening or closing the eyelids until the visual images disappear, occur during the morning or evening, but are not dependent on low light conditions.

Focal epilepsy
The visual hallucinations from focal epilepsy are characterized by being brief and stereotyped. They are usually localized to one part of the visual field, and last only a few seconds. , this type of focal epilepsy is caused by a lesion in the posterior temporoparietal

Schizophrenic hallucination
Hallucinations caused by schizophrenia.

Drug-induced hallucination
Hallucinations caused by the consumption of psychoactive substances.

Treatments
There are few treatments for many types of hallucinations.
those hallucinations caused by mental disease, a psychologist or psychiatrist should be alerted, and treatment will be based on the observations of those doctors.
Antipsychotic and atypical antipsychotic medication may also be utilized to treat the illness if the symptoms are severe and cause significant distress.
For other causes of hallucinations there is no factual evidence to support any one treatment is scientifically tested and proven. However, abstaining from hallucinogenic drugs, managing stress levels, living healthily, and getting plenty of sleep can help reduce the prevalence of hallucinations.
In all cases of hallucinations, medical attention should be sought out and informed of one's specific symptoms