Brief overview
- What are hallucinations? Sensory illusions that are experienced as real. All senses can be affected – hearing, smell, taste, sight, touch. Differences in intensity and duration are possible.
- Causes: e.g., lack of sleep, exhaustion, social isolation, migraine, tinnitus, eye disease, high fever, dehydration, hypothermia, stroke, traumatic brain injury, epilepsy, dementia, schizophrenia, depression, alcohol or other drugs, poisoning, medication.
- What does the doctor do? Preliminary interview (anamnesis), physical examination, blood tests if necessary and further measures such as ENT or eye examination, neurological examination, electroencephalography (EEG), computer tomography (CT), magnetic resonance imaging (MRI), psychological tests.
Hallucinations: Description
- Auditory hallucinations: Sufferers hear imaginary sounds, for example, hissing, cracking, or music.
- Teleological hallucinations: Special form of auditory hallucinations in which the affected person hears imaginary voices, for example, giving orders or warning of a supposed danger.
- Optical hallucinations: Affected persons see, for example, flashes of light or sparks, but also people, animals or objects that are not real.
- Taste hallucinations (gustatory hallucinations): These sensory illusions often occur together with olfactory hallucinations. Usually, the affected person registers an unpleasant (e.g., salty, soap-like, sulfurous, or fecal) odor.
- Body hallucinations (cenesthesias): In these sensory illusions, bodily sensation is disturbed. Typical is the conviction that the internal organs are altered or that the two hemispheres of the brain rub against each other. The transition between body and tactile hallucinations is fluid.
- Bodily hallucinations: Affected persons have the feeling that their body is being manipulated from the outside (e.g., irradiated or electrified).
- Vestibular hallucinations: Sufferers have the sensation of floating or falling.
- Hypnagogic and hypnopompic hallucinations: These mostly visual or auditory sensory delusions occur during half-sleep when falling asleep (hypnagogic) or when waking up (hypnopompe).
A hallucination usually starts suddenly. It lasts for a few hours, days or weeks, but can also become chronic and turn into delirium. In this state, the affected person can no longer absorb, process and store information in a structured manner. As a result, they can no longer orient themselves and remember things properly, and often hallucinate even more. In addition, there is anxiety, sometimes also agitation, as well as an acute danger to oneself or others.
Experts refer to hallucinosis as recurring hallucinations. However, the consciousness of the affected person is not impaired. One example is alcoholic hallucinosis – a psychosis with delusions of persecution and strong hallucinations, especially dermatozoa delusions, that occurs with long-term, chronic alcoholism. This refers to the feeling that small insects, worms, parasites, or other vermin are crawling on and under the skin.
Differentiation from pseudohallucinations
Distinction from delusions
While hallucinations are false sensory perceptions, delusions are false thoughts and beliefs, such as persecutory delusions. Sufferers cannot simply give them up, even if fellow human beings provide them with “proof to the contrary.”
Hallucinations: Causes
The main causes of hallucinations are:
- Marked lack of sleep or complete exhaustion.
- Social isolation, for example, solitary confinement or a prolonged stay in a low-stimulus environment (e.g., a dark, quiet room): Hallucinations are a natural reaction of the body to a lack of external stimuli. Sensory illusions during meditative exercises (spiritual ecstasy and visions) are considered special forms.
- Tinnitus (ringing in the ears): If there is ringing or rushing in the ear without an external sound source, tinnitus is present.
- Eye diseases such as retinal detachment, optic nerve damage or damage to the visual center can also cause optical hallucinations, for example, flashes of light, spots, patterns, spots of light or color.
- High fever: hallucinations with agitation, restlessness, lack of orientation, etc. may occur with high fever.
- Hypothermia: Hallucinations are also possible with severe hypothermia.
- Stroke: Hallucinations, delusions, confusion, impaired memory and consciousness may occur during a stroke.
- Craniocerebral trauma: Hallucinations and delusions sometimes occur in the context of craniocerebral injury.
- Epilepsy: In some cases, epileptic seizures are accompanied by sensory hallucinations, such as smell and taste hallucinations.
- Huntington’s disease (Huntington’s chorea): Huntington’s disease is a hereditary, progressive brain disease that causes movement disorders and mental changes. Hallucinations and delusions are also possible.
- Depression: Distressing hallucinations and/or delusions with dejection and lack of drive may be signs of depression.
- Alcohol abuse: Hallucinations (especially auditory sensory delusions) and delusions may occur during alcohol intoxication. Alcohol abusers may also develop hallucinations during withdrawal.
- Poisoning: Hallucinations and delusions associated with conspicuously dilated pupils indicate poisoning, such as with belladonna or datura. Parts of these plants are sometimes consumed as hallucinogenic drugs or accidentally eaten by children.
Hallucinations: When do you need to see a doctor?
Sensory illusions that occur, for example, when there is a pronounced lack of sleep, generally do not require medical attention. Otherwise, however, you should always consult a doctor in the event of a hallucination in order to clarify the possible cause. This applies especially in the following cases:
- Hallucinations and delusions when taking medication: Talk to the attending physician immediately.
- Hallucinations and delusions with conspicuously dilated pupils: Suspicion of poisoning (e.g. with datura or belladonna)! Immediately call the emergency doctor and do not leave the affected person alone!
- Hallucinations (like small animals on the skin) and delusions with anxious restlessness or agitation, confusion, impaired memory, and possibly impaired consciousness, sweating and trembling: Suspicion of acute organic psychosis and delirium in the case of alcohol withdrawal, high fever, hypothermia, stroke, encephalitis, etc. Call the emergency physician and do not leave the affected person alone.
Hallucinations: What does the doctor do?
The doctor will first ask the patient in detail about the medical history (anamnesis). It is important, for example, when and how often the hallucinations occur and what type they are. This information, possibly together with various examinations, will help the doctor to determine the cause of the hallucinations.
- Physical examination is routine when someone comes to the doctor with vague complaints such as hallucinations.
- ENT medical examinations are important when someone hears sounds that are not present (suspected tinnitus).
- An ophthalmological examination is due if certain eye diseases or damage to the optic nerve or visual center could be responsible for optical hallucinations.
- Neurological examination of the nerve pathways may be informative if, for example, migraine, stroke, epilepsy, or brain inflammation is a possible cause of hallucinations.
- Computed tomography (CT) and magnetic resonance imaging (MRI) can be helpful in cases of suspected stroke, encephalitis, traumatic brain injury, or dementia.
- An examination of cerebrospinal fluid (CSF) taken from the spinal cord (CSF puncture) is used to detect or rule out brain inflammation.
Hallucinations: What you can do yourself
Hallucinations are generally a case for the doctor and require treatment of the underlying condition. However, if pronounced lack of sleep and complete exhaustion are responsible for the sensory delusions, you can do something yourself: get a good night’s sleep and rest, and the hallucinations will disappear.
