Pathological laughter: characteristics and disorders associated with this symptom

Laughing is synonymous with happiness, joy and good humor. We should all incorporate the healthy exercise of having a laugh into our lives, since it has many benefits on a mental and physical level.

However, sometimes laughing for no reason and for no reason can be an indicator that something is wrong. This is known as pathological laughter, a symptom associated with psychopathology and neurological diseases which we are going to delve into next.

• Related article: "The 16 most common mental disorders"

What is pathological laughter?

Laughter is a fundamental aspect in our lives. It is the "symptom" that reflects a state of joy, being related to very healthy effects for our mental and physical health. However, sometimes, laughter can be truly a pathological symptom, indicating that something is not right at the brain level.

Normal laughter can be triggered by a reflex action, such as tickling. In this case, tickling causes laughter to occur through reflex mechanisms. It can also be triggered by witnessing a funny event, such as hearing a joke or seeing someone slip on a banana peel. Whether two such disparate situations can elicit the same response is still a mystery.

However, and as we were already commenting, sometimes laughter is a sign that something is not right. Pathological laughter is considered to be that which appears without reason, without being proportional to the emotional stimulus that supposedly triggered, rampant, uncontrolled, or appears to have no apparent relationship to the stimulus.

With what disorders is it related?

As we were already commenting, laughter, in general, is a symptom of health, happiness and good humor. However, it is also a sign of a health problem, whether of a medical or psychopathological origin, being much more stereotyped compared to normal laughter.

There are many disorders in which pathological laughter appears as a symptom. In most of them it appears as something uncontrollable, with incontinence and affective lability. Next we will look at various groups of medical and psychological problems in which pathological laughter can be found.

1. Neurological diseases

Pathological laughter characterizes certain diseases of the central nervous system, such as tumors, sclerosis multiple diseases, cerebral vascular diseases, dementias and head injuries, among other affectations at the highly strung.

1.1. Bulbar and pseudobulbar palsy

In bulbar and pseudobulbar palsy, there is a unilateral or bilateral lesion of the corticobulbar motor pathways, which is related to pathological laughter. Among the medical causes behind the appearance of these paralyzes we have arteriosclerosis, multiple cerebral infarction and multiple sclerosis.

In this case, laughter is characterized by its disproportion to the emotional stimulus that supposedly triggers it. In fact, it is often classified as emotional incontinence and can simulate a state of affective lability.

Among other symptoms of bulbar and pseudobulbar palsy we have not being able to make movements volunteers, although you can make reflex movements, such as laughter, crying and suction.

Among the brain regions affected in this neurological condition we have: the internal capsule, the substantia nigra, the cerebral peduncles and the caudal hypothalamus. In addition, there are bilateral lesions of the pyramidal tract, with involvement of extrapyramidal fibers.

1.2. Gelastic epilepsy

Gellastic epilepsy is characterized by the presence of sudden, paroxysmal-onset, self-limited laughter attacks caused by abnormal cortical discharges. This type of epilepsy was described in 1957 and its incidence is very small, 0.32%.

The crises are more frequent during the day, and is accompanied by hypotonia and diaphoresis (excessive sweating). These episodes last about 30 seconds and are usually followed by a phase of amnesia.

The seizures are more frequent in childhood, and are usually associated with the presence of hypothalamic tumors, which is in turn associated with the appearance of precocious puberty.

This type of epilepsy can begin in the first days of life, and its most common cause is usually tumors in the hypothalamus, called hypothalamic hamartomas, and more than half of those who suffer from it have problems at the intellectual.

• You may be interested: "Types of epilepsies: causes, symptoms and characteristics"

1.3. Cerebral vascular disease

A cerebrovascular disease, such as a stroke, can cause fits of laughter or crying pathological, generally due to damage to the vertebral or basilar arteries, occluding them partially.

A special case is the so-called ridenti stroke, in which there is prolonged laughter for hours, or even weeks, followed by hemiplegia, stupor or dementia. In this case, the disease is due to an active destruction of brain tissue due to extensive intracerebral hemorrhage, which gradually progresses.

2. Poisonings

Pathological laughter can be caused by poisoning or substance abuse. Some examples of substances that induce a non-normal laugh are hallucinogens (cannabis and hashish), LSD, alcohol, nitrous oxide (called, in fact, "laughing gas"), inhalation of insecticides, benzodiazepines in low concentrations or application of local anesthetics. It can also be caused by an accumulation of copper in brain tissues, a symptom of Wilson's disease.

• You may be interested: "Types of drugs: know their characteristics and effects"

3. Mental disorders

Pathological laughter is a symptom of various psychological disorders, and can be found in the phases manic bipolar disorder and also associated with drug addiction, as we have seen in the section previous. However, the most common pathological laughter associated with mental disorders is that which occurs in schizophrenia.

3.1. Schizophrenia

In the case of schizophrenia, laughter appears without any emotional sense, in the form of unprovoked or inappropriate outbursts, in the form of uncontrolled crises. Patients do not know why they are laughing, and they feel they are compelled to laugh.

Laughter can also appear in response to auditory hallucinations. Sometimes patients can quickly turn to crying. Laughter in schizophrenia has been viewed as very pathological.

3.2. Hysteria and other neuroses

Although hysteria is not currently a diagnosis within the DSM, this disorder has a long history, originally described by Sigmund Freud. He himself indicated that the repressed anxiety in hysteria can originate a specific affective state, which is accompanied by motor manifestations such as laughter.

In the case of hysteria, the appearance of pathological laughter has been associated with low socioeconomic status, anxiety, feelings of guilt, and loss of identity. Still, the contagious nature is not explained.

3.3. Narcolepsy

Narcolepsy manifests as daytime hypersomnolence, causing the person to fall asleep suddenly When I should be awake It is not known exactly what causes it, although it is known to have a hereditary component.

The person suffers from excessive daytime sleepiness, hypnagogic hallucinations, cataplexy, insomnia, and sleep paralysis.

The laughter that causes in this disorder is the trigger of cataplegic attacks, which consist of a sudden loss of muscle tone without a decrease in the level of consciousness, at a time when the patient is completely awake.

4. Pediatric disorders and diseases

There are several mental disorders and diseases that have their origin in childhood in which pathological laughter can be identified:

4.1. Angelman syndrome

Angelman syndrome was described in 1965 and is also called "happy puppet" syndrome. ("Happy puppet"). It is a multiple malformative syndrome, which affects patients of both sexes and of different races.

At the genetic level it resembles Prader Willi syndrome, although here the causes at the genetic level can be established in four types: maternal deletion (15q11-q13), paternal uniparental disomy, imprinting defects, and gene mutations UBE3A.

The main symptoms present in this syndrome are: severe mental retardation, especially in the language area, frequent laughter and happy appearance. This laugh is a characteristic feature of the syndrome, accompanied by a Machiavellian happy appearance. Also, they rarely or never cry.

Regarding somatic symptoms we can find microbrachycephaly, prognathism, tongue protrusion, malposition dental, occipital flattening, incoordinated body movements, ataxia, seizures and atrophy visual.

4.2. Autism spectrum disorders (ASD)

Autism Spectrum Disorders is the diagnostic label with which they have been encompassed, as an umbrella, various developmental disorders that until before DSM-5 were considered separate but related entities, What classic autism and Asperger syndrome.

Among the symptoms that occur in ASD we have: difficulties relating to and playing with other children, behaving as if they were deaf, great resistance to any learning, not being afraid of real dangers, resistance to routine changes, indicating needs through gestures, pathological laughter and not being affectionate among others symptom.

ASDs usually present before the age of three, and it is quite likely that there is some type of problem at the intellectual level, the exception being Asperger's syndrome.

4.3. Rett syndrome

Rett syndrome is a problem that courses with intellectual deficiency. So far it has only been described in girls and has been related to a mutation in the gene that encodes the transcription factor MeCP2, which can be verified in 95% of cases.

People diagnosed with this syndrome have autistic behavior and an inability to walk, growth retardation, eye abnormalities and stereotyped hand movements, among other signs and symptom. They present sudden laughter at night in more than 80% of cases.

Final reflection

Although laughter is something that should be present in our lives, due to its therapeutic value and because it is the materialization of happiness and joy, sometimes it is a sign that we have a problem. If we know someone, family member or friend, who has sudden fits of laughter without knowing why, perhaps it is an indicator that you have a medical illness or a psychological disorder, and that needs to be evaluated and addressed.

The best way to prevent a pathological situation from getting worse is to identify it early, and pathological laughter can be a symptom that warns us that the time to act has come.

Bibliographic references:

• De Gregorio, C., Martínez, B. (1998). Normal and pathological laughter. Historical antecedents, neuroanatomical and physiological bases, differential diagnosis. Public Psychiatry. 10: 19-25.
• Mora, R., García, M. C. (2008). The therapeutic value of laughter in medicine. Med Clin; 131: 694-8.
• Lancheros, E. A., Tovar, J., Rojas, C. (2011). Laughter and health: therapeutic approaches. Med UNAB. 14: 69-75.