VISUAL HALLUCINATIONS: CAUSES, TYPES AND TREATMENT - ECONOMÍA - 2024

The visual hallucinations consist of the perception of an element that is not really present and appear in both children and the elderly. Its causes are very diverse, and are commonly associated with schizophrenia or the use of certain drugs, although they can also appear due to stress.

Even the "healthy" population can experience hallucinations throughout their lives, such as those that occur when falling asleep (hypnagogic) or waking up (hypnopompic). On the other hand, there are many types of visual hallucinations; from simple optical experiences such as flashes or colors, to complex constructions such as objects, people, animals or insects.

Treatment for visual hallucinations consists of controlling the underlying causes (stress, fever, lack of sleep, addiction to drugs or alcohol…), medication (for psychiatric illnesses), and cognitive-behavioral therapy so that the patient learns to distinguish and control your own hallucinations.

Characteristics of visual hallucinations

Visual hallucinations are characterized by:

- Alterations in perception that occur without the hallucinated object being present in the visual field of the person.

- The person who experiences it is convinced that the element is real, adapting their behavior to them. That is why it is difficult for these people to recognize or identify their hallucinations.

- They usually have organic causes, involving the visual pathways and association areas of the brain.

Difference from pseudohallucinations

It is important not to confuse visual hallucinations with pseudo-hallucinations. The latter are characterized by the existence of a certain preservation of the judgment of reality. That is, the person who experiences them may suspect or know that what he is experiencing is not real.

Furthermore, pseudo-hallucination is more inaccurate, diffuse, and imprecise; and its details can be modified to some extent of their own free will. On the other hand, hallucinations themselves are sharp, detailed, and persistent, and cannot be changed by our will, nor are they influenced by suggestion.

When are hallucinations pathological?

Hallucinations become pathological when:

- Are frequent

- They are part of diseases, disorders or syndromes

- They cause discomfort, preventing the person from leading a satisfactory life.

- They negatively affect the people around them and, therefore, interpersonal relationships.

Types

Hallucinations have been classified in many different ways, each author relying on different criteria.

Visual hallucinations according to the degree of complexity

- Simple or elementary: they are the simplest and they are simple geometric shapes, lights, flashes, colors… They are called photopsies or photomes.

- Complex: they are very real and elaborate. Subjects with these types of hallucinations can vividly observe animals, objects, people, scenes, etc. In great detail, as if it were a real event.

According to the size

- Lilliputians: seeing small beings, usually people or animals; although small objects can also be seen. It is a miniature world, viewed in a pleasant mood. It is frequent that it is produced by the excessive consumption of some drug.

- Gulliverian: the opposite of the above, consists of seeing people, animals or gigantic objects.

As perceived or not

- Positive: they perceive a visual element that does not exist in the environment.

- Negative: They cannot perceive an element that does exist.

According to the content

- Objects that can be familiar, strange and even non-existent.

- Animals, monsters and insects. When they are unpleasant or terrifying, they are called zoopsias. For example, the patient may see the heads of lions trying to devour him. Zoopsias are common in alcoholics.

- Persons

- Stains (such as blood or mud)

- According to fears, wishes, expectations, memories…

- Of a religious or cultural nature

- Related to the presence of certain delusions (such as seeing cameras installed in your home if you have delusions of persecution).

According to the mood

- Congruent with the mood: if the person is depressed, for example, the hallucinations will be annoying according to their concerns.

- Not congruent with mood: no relationship is found between the person's mood and the theme of his hallucinations.

During the dream

When we fall asleep, our brain activity goes through different phases that change during sleep. These transitions of brain activity, naturally, can manifest in hallucinations.

- Hypnopompic: the visual hallucinations that occur on waking.

- Hypnagogic: those that arise when we are falling asleep.

Autoscopic

Regarding ourselves, they can be:

- Autoscopy: see ourselves within our visual field, as if it were a clone.

- Negative autoscopy: we do not see our image reflected in the mirror.

Causes

The causes of visual hallucinations are very varied, ranging from stress or exhaustion to psychiatric disorders or certain syndromes.

Ophthalmic disorders or eye injuries

They are usually simple hallucinations like lights and geometric shapes that move. They appear as a consequence of conditions such as cataracts, glaucoma, retinal detachment, vitreous traction… among others.

Lesions in the brain anatomical substrate of vision

They are those areas of the nervous system that process visual information, such as the optic nerves, the optic chiasm, areas of the brain stem (such as the cerebral peduncle), the occipital lobe of the brain, etc.

On the other hand, an involvement in the primary visual cortex would cause simple hallucinations, while a lesion in the visual association cortex would cause complex visual hallucinations.

Prolonged visual deprivation

If we stay for several days blindfolded or in a dark environment, we can experience hallucinations when we return to the normal environment. This may be due to hypersensitivity to visual stimulation due to lack of it.

This fact was demonstrated in a study of 13 healthy subjects who had their eyes covered for 5 days. 10 of them experienced visual hallucinations after removal of the bandage (Merabet et al., 2004).

Schizophrenia

In schizophrenia hallucinations are a symptom. Usually the most frequent are those of the auditory type (such as hearing voices), but they can also be visual (16% - 72%). This variability of the percentage is due to the severity of the schizophrenia that the subjects present. That is, the more severe the schizophrenia of the participants evaluated in the study, the more likely they will have visual hallucinations.

It seems that the appearance of hallucinations is associated in these cases with a lack of dopamine regulation in the mesolimbic pathway of the brain. Specifically, an excess of dopamine or dopamine receptors in this region.

Dementia

They encompass a group of diseases that have progressive brain degeneration in common.

Visual hallucinations can appear when diseases such as Alzheimer's or Parkinson's are in more advanced stages and begin to affect areas responsible for visual processing.

Charles Bonnet syndrome

It is a non-psychiatric cause of visual hallucinations in which patients have visual problems such as glaucoma, cataracts, or macular degeneration.

Hallucinations are always visual and tend to be complex, the mental health of these patients being intact. At first they are not aware that they have hallucinations, but little by little they are realizing that they have them.

Epilepsy

In some cases, during epileptic seizures, visual hallucinations may arise. They are usually simple and short, consisting of bright colors or lights that change shape.

This is because parts of the brain that control vision are overactive.

Brain tumors or strokes that affect visual areas

In fact, suddenly beginning to suffer from visual hallucinations, along with other symptoms, can be a sign of the presence of a brain tumor.

Substance abuse, drug intoxication, or withdrawal syndrome

There are certain drugs such as LSD, PCP or hallucinogenic mushrooms that can cause hallucinations of different levels. However, they are usually pseudo-hallucinations since normally those who consume it know how to distinguish between hallucinations and reality.

Drinking too much alcohol, your withdrawal, or drugs like cocaine and ether can also cause hallucinations.

Lack of sleep

A person who goes several days without sleep (approximately three days), or does not get enough sleep for long periods of time, is prone to hallucinations.

It seems that when we are awake our brain secretes adenosine. This has inhibitory and sedative effects, and if it accumulates in large quantities in our brain, it can cause hallucinations.

Side effects of medications

Certain medications taken for mental and physical conditions can also cause hallucinations. Some of them are aspirin, apomorphine, Ropinirole (for Parkinson's), propranolol (for hypertension), atenolol, enflurane… among others.

Migraines

Between 15% and 29% of the general population suffer from migraines. Within this group, up to 31% have an "aura." Auras usually occur before or while the headache is present, and involves visual hallucinations (in 90%). Specifically, the person experiencing it sees flashes that blink in zig-zag movements.

Stress

Intense stress or prolonged isolation can cause visual hallucinations. The latter usually happens in older people who live alone. On the other hand, stress can cause brief pictures of visual hallucinations. In fact, in studies with prisoners, up to 25% of the subjects have suffered them (Ronald, 1984).

Other causes

- Heavy metal poisoning

- Diseases such as kidney or liver failure, encephalitis, HIV, and uremia

- High fever, especially in children and the elderly

- Altered states of consciousness.

Treatment

Treatment for hallucinations depends on the causes that caused them. First you have to detect what is causing the hallucinations and thus get the right treatment, that is why it is important that the correct diagnosis is made.

In addition, a treatment that may be beneficial for visual hallucinations caused by a certain cause, may be negative if the cause is another.

Delirium tremens

For example, benzodiazepines may be useful for hallucinations typical of delirium tremens. However, if the hallucinations are due to another cause, benzodiazepines can exacerbate these hallucinations.

Psychotic illnesses

If the hallucinations are the result of psychotic illnesses, neuroleptic drugs that are dopamine antagonists such as haloperidol are recommended. In addition, these medications also treat delusions (very strong beliefs that do not fit with the logic, or with the culture of the individual, common in psychosis).

Alzheimer's

For dementias such as Alzheimer's disease, cholineterase inhibitors such as galantamine, donepezil, and rivastigmine are recommended in mild and moderate stages.

Migraines

For migraines, triptans (sumatriptan, zolmitriptan) or beta blockers seem effective. Epilepsy should be treated with anticonvulsants, and tumors with radiation and surgery.

However, there are some cases in which visual hallucinations do not have a direct treatment. In these cases, neuroleptics are used to minimize them and other types of therapy such as psychological.

Cognitive behavioral therapy

Thanks to cognitive behavioral therapy, these patients can learn about hallucinations, what their causes are, come to recognize that they suffer from hallucinations, and train in the difficult task of identifying when they appear. At this point, patients are taught to ignore the visual elements resulting from the hallucination.

Obviously, to enhance the effects of any intervention it is essential that people maintain good habits such as sleeping the necessary hours each night, treating insomnia or stress if it exists, and abandoning the use of drugs and other addictive substances.

In the case of side effects of a drug, it may be useful to replace it with another that has the same mechanism of action, but does not produce visual hallucinations.

References

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3. Merabet LB, Maguire D., Warde A., et al. (2004). Visual hallucinations during prolonged blindfolding in sighted subjects. J Neuroophthalmol; 24 (2): 109-113.
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