Pathological laughter: characteristics and disorders associated with this symptom

Laughter is synonymous with happiness, joy and good humor. We should all incorporate the healthy exercise of laughing a little into our lives as it has so many benefits both mentally and physically.

However, sometimes laughing for no reason and without something being appropriate can be an indicator that something is wrong. This is known as pathological laughter, a symptom associated with psychopathology and neurological diseases in which we will dig deeper below.

    What is pathological laughter?

    Laughter is a fundamental aspect of our lives. It is the “symptom” that reflects a state of joy, being linked to very healthy effects on our mental and physical health. However, sometimes laughing can really be a pathological symptom, indicating that something is wrong with the brain.

    Normal laughter can be triggered by a reflective act, such as tickling. In this case, the tickling induces laughter through reflex mechanisms. It can also be triggered by witnessing a funny event, such as hearing a joke or watching someone slip on a banana peel. Whether two such disparate situations can elicit the same response remains a mystery.

    However, and as we were already talking about, laughing is sometimes a sign that something is wrong. Pathological laughter is considered to be that which appears without reason, without being proportional to the emotional stimulus which would have triggered it, unbridled, uncontrolled or which appears without any apparent relation to the stimulus.

    What disorders is it linked to?

    As we said before, laughter, in general, is a symptom of health, happiness and good humor. However, it is also a sign of a health problem, whether of medical or psychopathological origin, showing it to be much more stereotypical than normal laughter.

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

    1. Neurological diseases

    Pathological laughter characterizes certain diseases of the central nervous system, such as tumors, multiple sclerosis, cerebrovascular disease, dementia and cranioencephalic trauma, among other nervous disorders.

    1.1. Bulbar and pseudobulbar palsy

    Bulbar and pseudobulbar palsy is a unilateral or bilateral lesion of the corticobulbar motor pathways, which is linked to pathological laughter. Some of the medical causes for the onset of these paralyzes include arteriosclerosis, multiple stroke, and multiple sclerosis.

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

    Among the other symptoms of bulbar and pseudobulbar palsy, we are unable to make voluntary movements, although reflex movements can be made, as is the case with laughing, crying, and sucking.

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

    1.2. Gelastic epilepsy

    Gelastic epilepsy is characterized by the presence of sudden attacks of laughter that appear paroxysmal, self-limiting and produced by abnormal cortical discharges. This type of epilepsy was described in 1957 and its incidence is very low, 0.32%.

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

    Seizures are more common in childhood and are often associated with the presence of hypothalamic tumors, which in turn are associated with the onset of precocious puberty.

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

      1.3. Cerebrovascular disease

      Cerebral vascular disease, such as a stroke, can cause pathological attacks of laughter or crying, usually due to damage to the vertebral or basilar arteries, partially occluding them.

      A special case is the so-called laughter, 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 active destruction of brain tissue due to extensive intracerebral hemorrhage, which gradually progresses.

      2. Poisonings

      Pathological laughter can be caused by poisoning or drug addiction. a few examples of substances that cause abnormal laughter are hallucinogens (cannabis and hashish), LSD, alcohol, Nitrous oxide (actually called “laughter gas”), inhalation of insecticides, low concentrations of benzodiazepines or application of local anesthetics. It can also be caused by a buildup of copper in brain tissue, a symptom of Wilson’s disease.

        3. Mental disorders

        Pathological laughter is a symptom of several psychological disorders, and can be found in the manic phases of bipolar disorder and also associated with addictions, as we saw in the previous section. 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 significance, in the form of unprovoked or inappropriate outbursts, in the form of uncontrolled seizures. Patients don’t know why they are laughing and they feel 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 a very pathological thing.

        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 has indicated that pent-up anxiety in hysteria can give rise to a specific affective state, which is accompanied by motor manifestations such as laughter.

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

        3.3. narcolepsy

        Narcolepsy manifests itself in the form of daytime hypersomnolence, causing the person to suddenly fall asleep when she should be awake. It is not known exactly what causes it, although it is known to have an inherited component.

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

        The laughter it induces in this disorder is the trigger for cataplexic attacks, which consist of a sudden loss of muscle tone without a decrease in level of consciousness, when the patient is fully 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 first described in 1965 and is also referred to as “happy puppet” syndrome. (“Happy Puppet”). It is a multiple malformation syndrome, which affects patients of both sexes and different races.

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

        The main symptoms present in this syndrome are: severe mental retardation, especially in the area of ​​language, frequent laughter and happy appearance. This laughter is a characteristic trait of the syndrome, accompanied by a cheerful Machiavellian appearance. Plus, they rarely cry or even fan cry.

        As for the somatic symptoms, we can find microbrachycephaly, prognathism, lingual protrusion, tooth malposition, occipital flattening, uncoordinated body movements, ataxia, convulsions and visual atrophy.

        4.2. Autism Spectrum Disorders (ASD)

        Autism Spectrum Disorders is the diagnostic label that has included, as an umbrella, several developmental disorders that, until before DSM-5, were considered separate but related entities, such as classical autism and Asperger’s syndrome.

        Symptoms of ASD include: difficulty interacting and playing with other children, behaving deaf, high resistance to learning, fear of real dangers, resistance to changes in routine, indication of needs through gestures, pathological laughter and not not be affectionate among other symptoms.

        ASDs usually present before the age of three, And it is highly likely that some sort of problem occurs intellectually, with the exception of Asperger’s syndrome.

        4.3. Rett syndrome

        Rett syndrome is a problem that race with intellectual disability. To date, it has only been described in girls and has been linked to a mutation in the gene encoding the transcription factor MeCP2, which can be verified in 95% of cases.

        People diagnosed with this syndrome exhibit autistic behavior and inability to walk, stunted growth, eye disorders, and stereotypical hand movements, among other signs and symptoms. They present with sudden laughter at night in over 80% of cases.

        final thought

        Although laughter is something that must be present in our lives, for its therapeutic value and to be the materialization of happiness and joy, sometimes it is a sign that you are suffering from a problem. If we know someone, family or a friend, who suddenly bursts into laughter, we know why, it may be an indicator that you are suffering from a medical illness or psychological disorder, And this needs to be evaluated and dealt with.

        The best way to prevent a pathological situation from worsening is to identify it in time, and pathological laughter can be a symptom that alerts us that the time has come to act.

        Bibliographical references:

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

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