Hallucination is a profound distortion in a person’s perception of reality, typically accompanied by a powerful sense of reality. An hallucination may be a sensory experience in which a person can see, hear, smell, taste, or feel something that is not there.

Causes of hallucinations include:

  • Being drunk or high, or coming down from such drugs like marijuana, LSD, cocaine (including crack), PCP, amphetamines, heroin, ketamine, and alcohol
  • Delirium or dementia (visual hallucinations are most common)
  • Epilepsy that involves a part of the brain called the temporal lobe (odor hallucinations are most common)
  • Fever, especially in children and the older people
  • Narcolepsy (disorder that causes a person to fall into periods of deep sleep)
  • Mental disorders, such as schizophrenia and psychotic depression
  • Sensory problem, such as blindness or deafness
  • Severe illness, including liver failure, kidney failure, HIV/AIDS, and brain cancer
  • An auditory hallucination involves the sense of hearing; also called paracusia and paracusis.
  • A gustatory hallucination involves the sense of taste.
  • A hypnagogic hallucination is a vivid dreamlike hallucination at the onset of sleep.
  • Hypnopompic hallucination is a vivid dreamlike hallucination on awakening.
  • Kinesthetic hallucination involves the sense of bodily movement.
  • Lilliputian hallucination is an hallucination in which things, people, or animals seem smaller than they would be in reality.
  • Olfactory hallucination involves the sense of smell.
  • Somatic hallucination involves the perception of a physical experience occurring with the body.
  • Tactile hallucination involves the sense of touch.
  • Visual hallucination involves the sense of sight.

Certain measures can be taken to prevent or reduce hallucination, although a psychologist or psychiatrist may need to be consulted in cases of hallucination caused by mental illness. If hallucinations are causing significant distress, antipsychotic medication may be prescribed.

Some of the approaches used to treat hallucination are described below:

  • General measures that can be taken to reduce the frequency or severity of hallucinations include stress management, healthy living, regular exercise and sleeping well.
  • The use of illicit drugs such as cocaine, LSD, amphetamines or ecstasy can cause hallucinations. Excessive alcohol consumption is another cause. These hallucinations can occur during periods of withdrawal from drugs or alcohol if the substances are stopped too suddenly. People experiencing hallucinations due to drugs or alcohol withdrawal can be given medication to help prevent the hallucinations occurring. Rehabilitation programs are also available to help the patient recover from their addiction.
  • Psychosocial strategies used to help manage hallucination include education and counselling to help the patient and their family cope with the hallucinations and understand the importance of medication compliance.
  • Examples of antipsychotic medications used to treat hallucinations include haloperidol, olanzapine and risperidone.
  • Hallucinations can occur as a side effect of the treatment for Parkinson’s disease. If this occurs, the patient’s medication may require adjustment. Usually, amantadine and anticholinergics are stopped first. Thereafter, dopamine agonists may be withdrawn. Clozapine and quetiapine are examples of neuroleptic drugs that may help treat hallucinations in Parkinson’s disease.
  • Other problems that occur as a result of hallucination such as memory disturbance, sleep disorder, depression, anxiety and associated panic attacks may also need to be managed with treatment.

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