Jumping Frenchmen of Maine syndrome must be distinguished from other conditions involving the startle reflex or tics.

Tourette syndrome is characterized by multiple physical (motor) tics and at least one vocal (phonic) tic. There are many overlaps when compared clinically, but the abnormal "jumping" response is always provoked, unlike the involuntary tics in Tourette syndrome.

Latah from Southeast Asia is a disorder where one's startle response is similar to a state of trance with repetitive speech or movements. Miryachit is a disorder found in Siberia that also displays an action similar to "jumping". Neurasthenia is a disorder with a startle response during periods of great fatigue.

Hyperekplexia is an extremely rare autosomal dominant neurological disease. The symptoms start in infancy with hypertonia, an abnormal muscle tension that decreases flexibility, and an exaggerated startle in all ages of life.

George Miller Beard recorded individuals who would obey any command given suddenly, even if it meant striking a loved one; the Jumping Frenchmen seemed to react abnormally to sudden stimuli. The more common and less intense symptoms consisted of jumping, yelling, and hitting. These individuals exhibited outrageous bursts, and many described themselves as ticklish and shy. Other cases involved echolalia (repeating vocalizations made by another person) and echopraxia (repeating movements made by another person). Beard noted that the men were "suggestible" and that they "could not help repeating the word or sounds that came from the person that ordered them any more than they could help striking, dropping, throwing, jumping, or starting".

There are a great number of symptoms experienced by those with a functional neurological disorder. It is important to note that the symptoms experienced by those with an FND are very real , and should not be confused with malingering, factitious disorders, or Munchausen syndrome. At the same time, the origin of symptoms is complex since it can be associated with physical injury, severe psychological trauma (conversion disorder), and idiopathic neurological dysfunction. The core symptoms are those of motor or sensory function or episodes of altered awareness

- Limb weakness or paralysis

- Blackouts (also called dissociative or non-epileptic seizures/attacks) – these may look like epileptic seizures or faints

- Movement disorders including tremors, dystonia (spasms), myoclonus (jerky movements)

- Visual symptoms including loss of vision or double vision

- Speech symptoms including dysphonia (whispering speech), slurred or stuttering speech

- Sensory disturbance including hemisensory syndrome (altered sensation down one side of the body)

Functional neurological disorders are a common problem, and are the second most common reason for a neurological outpatient visit after headache/migraine. Dissociative (non-epileptic) seizures account for about 1 in 7 referrals to neurologists after an initial seizure, and functional weakness has a similar prevalence to multiple sclerosis.

Conversion disorder begins with some stressor, trauma, or psychological distress. Usually the physical symptoms of the syndrome affect the senses or movement. Common symptoms include blindness, partial or total paralysis, inability to speak, deafness, numbness, difficulty swallowing, incontinence, balance problems, seizures, tremors, and difficulty walking. These symptoms are attributed to conversion disorder when a medical explanation for the afflictions cannot be found. Symptoms of conversion disorder usually occur suddenly. Conversion disorder is typically seen in individuals aged 10 to 35, and affects between 0.011% and 0.5% of the general population.

Conversion disorder can present with motor or sensory symptoms including any of the following:

Motor symptoms or deficits:

- Impaired coordination or balance

- Weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)

- Impairment or loss of speech (hysterical aphonia)

- Difficulty swallowing (dysphagia) or a sensation of a lump in the throat

- Urinary retention

- Psychogenic non-epileptic seizures or convulsions

- Persistent dystonia

- Tremor, myoclonus or other movement disorders

- Gait problems (astasia-abasia)

- Loss of consciousness (fainting)

Sensory symptoms or deficits:

- Impaired vision (hysterical blindness), double vision

- Impaired hearing (deafness)

- Loss or disturbance of touch or pain sensation

Conversion symptoms typically do not conform to known anatomical pathways and physiological mechanisms. It has sometimes been stated that the presenting symptoms tend to reflect the patient's own understanding of anatomy and that the less medical knowledge a person has, the more implausible are the presenting symptoms. However, no systematic studies have yet been performed to substantiate this statement.

Latah, from Southeast Asia, is a condition in which abnormal behaviors result from a person experiencing a sudden shock. When surprised, the affected person typically engages in such behaviors as screaming, cursing, dancing type movements, and uncontrollable laughter, and will typically mimic the words or actions of those around them. Physical symptoms include an increased heart rate and profuse sweating, but no clear physiological source has been identified.

Latah is considered a culture-specific startle disorder that was historically regarded as personal difference rather than an illness.

Similar conditions have been recorded within other cultures and locations. For example, there are the so-called Jumping Frenchmen of Maine, the women of the Ainu people of Japan ("imu"), the Siberian ("miryachit"), and the Filipino and Thai peoples; however, the connection among these syndromes is controversial.

Conversion disorder presents with symptoms that typically resemble a neurological disorder such as stroke, multiple sclerosis, epilepsy or hypokalemic periodic paralysis. The neurologist must carefully exclude neurological disease, through examination and appropriate investigations. However, it is not uncommon for patients with neurological disease to also have conversion disorder.

In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder, i.e. certain aspects of the presentation that were thought to be rare in neurological disease but common in conversion. The validity of many of these signs has been questioned, however, by a study showing that they also occur in neurological disease. One such symptom, for example, is "la belle indifférence", described in DSM-IV as "a relative lack of concern about the nature or implications of the symptoms". In a later study, no evidence was found that patients with functional symptoms are any more likely to exhibit this than patients with a confirmed organic disease. In DSM-V, "la belle indifférence" was removed as a diagnostic criteria.

Another feature thought to be important was that symptoms tended to be more severe on the non-dominant (usually left) side of the body. There have been a number of theories about this, such as the relative involvement of cerebral hemispheres in emotional processing, or more simply, that it was "easier" to live with a functional deficit on the non-dominant side. However, a literature review of 121 studies established that this was not true, with publication bias the most likely explanation for this commonly held view. Although agitation is often assumed to be a positive sign of conversion disorder, release of epinephrine is a well-demonstrated cause of paralysis from hypokalemic periodic paralysis.

Misdiagnosis does sometimes occur. In a highly influential study from the 1960s, Eliot Slater demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder. Later authors have argued that the paper was flawed, however, and a meta-analysis has shown that misdiagnosis rates since that paper was published are around 4%, the same as for other neurological diseases.

Developmental coordination disorder is classified (by doctors) in the fifth revision of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-5) as a motor disorder, in the category of neurodevelopmental disorders.

Various areas of development can be affected by developmental coordination disorder and these will persist into adulthood, as DCD has no cure. Often various coping strategies are developed, and these can be enhanced through occupational therapy, psychomotor therapy, physiotherapy, speech therapy, or psychological training.

In addition to the physical impairments, developmental coordination disorder is associated with problems with memory, especially working memory. This typically results in difficulty remembering instructions, difficulty organizing one's time and remembering deadlines, increased propensity to lose things or problems carrying out tasks which require remembering several steps in sequence (such as cooking). Whilst most of the general population experience these problems to some extent, they have a much more significant impact on the lives of dyspraxic people. However, many dyspraxics have excellent long-term memories, despite poor short-term memory. Many dyspraxics benefit from working in a structured environment, as repeating the same routine minimises difficulty with time-management and allows them to commit procedures to long-term memory.

People with developmental coordination disorder sometimes have difficulty moderating the amount of sensory information that their body is constantly sending them, so as a result dyspraxics are prone to sensory overload and panic attacks.

Many dyspraxics struggle to distinguish left from right, even as adults, and have extremely poor sense of direction generally.

Moderate to extreme difficulty doing physical tasks is experienced by some dyspraxics, and fatigue is common because so much extra energy is expended while trying to execute physical movements correctly. Some (but not all) dyspraxics suffer from hypotonia, low muscle tone, which like DCD can detrimentally affect balance.

Since astasis itself is more a symptom than a disease, it is more often seen associated with other signs and symptoms. People who have astasis often experience

- Odd gyrations

- Tightrope balancing deficits (in which a person attempts to balance on a tightrope in order to test balance and motor coordination)

- Near falling deficits (which is a test in which the patient is slightly pushed in order to check their ability to regain posture)

- Exaggerated effort deficits (which is an overcompensation test used to determine motor coordination ability)

- Atypical postures and weakness

- Paralysis

- Jumping fits (in which motor control is partially or totally lost)

- Tremors

One study described a patient with astasis as lying in bed with a normal body posture. When the patient was sitting, he tilted his body to the left. When he was asked to stand up, the patient rotated his trunk axis to the left (left shoulder going backwards), and tilted his body to that same side, showing resistance to passive correction of posture in both of these planes. He was unable to stand and fell backwards and towards the left.

Neuroferritinopathy has several distinguishing signs and symptoms. These fall into two categories: diagnostic findings and physically visible symptoms.

Symptoms categorized as physically visible symptoms include chorea, dystonia, spasticity, and rigidity, all physical symptoms of the body associated with movement disorders. The symptoms accompanying neuroferritinopathy affecting movement are also progressive, becoming more generalized with time. Usually during the first ten years of onset of the disease only one or two limbs are directly affected.

Distinctive symptoms of neuroferritinopathy are chorea, found in 50% of diagnosed patients, dystonia, found in 43% of patients, and parkinsonism, found in 7.5% of patients. Full control of upper limbs on the body generally remains until late onset of the disease. Over time, symptoms seen in a patient can change from one side of the body to the opposite side of the body, jumping from left to right or vice versa. Another route that the physically visible symptoms have been observed to take is the appearance, disappearance, and then reappearance once more of specific symptoms.

While these symptoms are the classic indicators of neuroferritinopathy, symptoms will vary from patient to patient.

Latah can affect people differently; someone can have a very strong reaction or a slight reaction during a latah episode. Every instance of latah has been acquired over time. Those who are affected, which by an overwhelming number are middle-to-older-aged women, are not born latah. It typically occurs around the time of menopause. There is a lack of latah in the higher social strata of Malay and Java, which suggests they are more likely to suppress their responses than those who belong to lower social classes.

A latah episode occurs after a startle of some sort (poking, shouting, something falling). During an episode, a latah person will begin to shout obscenities, imitate words or gestures of those around them or even those on TV, and will often obey any commands given to them – no matter how outrageous or against cultural norms they are. Persons with latah make movements reminiscent of behaviors normally peculiar to certain childhood developmental stages. The person is unlikely to remember anything occurring during the episode.

""Astasia" redirects here. This term was also applied to chlorophyll-less "Euglena.

Astasis is a lack of motor coordination marked by an inability to stand, walk or even sit without assistance due to disruption of muscle coordination.

The term "astasia" is interchangeable with "astasis" and is most commonly referred to as "astasia" in the literature describing it. Astasis is the inability to stand or sit up without assistance in the absence of motor weakness or sensory loss (although the inclusion of 'the lack of motor weakness' has been debated by some physicians). It is categorized more as a symptom than an actual disease, as it describes a disruption of muscle coordination resulting in this deficit. The disturbance differs from cerebellar ataxia in that with astasis the gait can be relatively normal, with balance significantly impaired during transition from a seated to standing position. This balance impairment is similar to patients with vestibulocerebellar syndrome, which is a progressive neurological disease with many symptoms and effects.

Astasis has been seen in patients with diverse thalamic lesions, predominantly affecting the posterior lateral region of the brain. It is most frequently accompanied by abasia, although not always. Abasia is a symptom very similar to it and is the inability to walk. The two are most commonly seen in astasia-abasia, which is also called Blocq's disease. It is more common for astasia and abasia to be seen together than it is to see either one or the other.

Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder (more specifically a parasomnia) that involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. It was first described in 1986.

The major and arguably only abnormal feature of RBD is loss of muscle atonia (i.e., the loss of paralysis) during otherwise intact REM sleep (during which paralysis is not only normal but necessary). REM sleep is the stage of sleep in which most vivid dreaming occurs. The loss of motor inhibition leads to a wide spectrum of behavioral release during sleep. This extends from simple limb twitches to more complex integrated movement, in which people appear to be unconsciously acting out their dreams. These behaviors can be violent in nature and in some cases will result in injury to either the patient or their bed partner.

For people with this disorder, cognition and sensation are otherwise normal; for instance, patients can still feel discriminative touch (though not always temperature), and there are no detectable physical abnormalities.

Because children with the disorder cannot feel pain, they may not respond to problems, thus being at a higher risk of more severe diseases. Children with this condition often suffer oral cavity damage both in and around the oral cavity (such as having bitten off the tip of their tongue) or fractures to bones. Unnoticed infections and corneal damage due to foreign objects in the eye are also seen.

There are generally two types of non-response exhibited:

- Insensitivity to pain means that the painful stimulus is not even perceived: a patient cannot describe the intensity or type of pain.

- Indifference to pain means that the patient can perceive the stimulus, but lacks an appropriate response: they do not flinch or withdraw when exposed to pain.

Rapid eye movement behavior disorder (RBD) occurs when there is a loss of normal voluntary muscle atonia during REM sleep resulting in motor behavior in response to dream content. It can be caused by adverse reactions to certain drugs or during drug withdrawal; however, it is most often associated with the elderly and in those with neurodegenerative disorders such as Parkinson disease and other neurodegenerative diseases, for example multiple system atrophy and Lewy body dementia.

RBD is categorized as either idiopathic or symptomatic.

Dancing mania (also known as dancing plague, choreomania, St John's Dance and, historically, St. Vitus's Dance) was a social phenomenon that occurred primarily in mainland Europe between the 14th and 17th centuries. It involved groups of people dancing erratically, sometimes thousands at a time. The mania affected men, women, and children who danced until they collapsed from exhaustion. One of the first major outbreaks was in Aachen, in the Holy Roman Empire, in 1374, and it quickly spread throughout Europe; one particularly notable outbreak occurred in Strasbourg in 1518, also in the Holy Roman Empire.

Affecting thousands of people across several centuries, dancing mania was not an isolated event, and was well documented in contemporary reports. It was nevertheless poorly understood, and remedies were based on guesswork. Generally, musicians accompanied dancers, to help ward off the mania, but this tactic sometimes backfired by encouraging more to join in. There is no consensus among modern-day scholars as to the cause of dancing mania.

The several theories proposed range from religious cults being behind the processions to people dancing to relieve themselves of stress and put the poverty of the period out of their minds. It is, however, thought to have been a mass psychogenic illness in which the occurrence of similar physical symptoms, with no known physical cause, affect a large or small group of people as a form of social influence.

Animal hoarding is keeping a higher-than-usual number of animals as domestic pets without ability to properly house or care for them, while at the same time denying this inability. Compulsive hoarding can be characterized as a symptom of mental disorder rather than deliberate cruelty towards animals. Hoarders are deeply attached to their pets and find it extremely difficult to let the pets go. They typically cannot comprehend that they are harming their pets by failing to provide them with proper care. Hoarders tend to believe that they provide the right amount of care for them. The American Society for the Prevention of Cruelty to Animals provides a "Hoarding Prevention Team", which works with hoarders to help them attain a manageable and healthy number of pets.

Congenital insensitivity to pain (CIP), also known as congenital analgesia, is one or more rare conditions in which a person cannot feel (and has never felt) physical pain. The conditions described here are separate from the HSAN group of disorders, which have more specific signs and cause. Because feeling physical pain is vital for survival, CIP is an extremely dangerous condition. It is common for people with the condition to die in childhood due to injuries or illnesses going unnoticed. Burn injuries are one of the more common injuries.

The outbreaks of dancing mania varied, and several characteristics of it have been recorded. Generally occurring in times of hardship, up to tens of thousands of people would appear to dance for hours, days, weeks, and even months.

Women have often been portrayed in modern literature as the usual participants in dancing mania, although contemporary sources suggest otherwise. Whether the dancing was spontaneous, or an organised event, is also debated. What is certain, however, is that dancers seemed to be in a state of unconsciousness, and unable to control themselves.

In his research into social phenomena, author Robert Bartholomew notes that contemporary sources record that participants often did not reside where the dancing took place. Such people would travel from place to place, and others would join them along the way. With them they brought customs and behaviour that were strange to the local people. Bartholomew describes how dancers wore "strange, colorful attire" and "held wooden sticks".

Robert Marks, in his study of hypnotism, notes that some decorated their hair with garlands. However, not all outbreaks involved foreigners, and not all were particularly calm. Bartholomew notes that some "paraded around naked" and made "obscene gestures". Some even had sexual intercourse. Others acted like animals, and jumped, hopped and leaped about.

They hardly stopped, and some danced until they broke their ribs and subsequently died. Throughout, dancers screamed, laughed, or cried, and some sang. Bartholomew also notes that observers of dancing mania were sometimes treated violently if they refused to join in. Participants demonstrated odd reactions to the colour red; in "A History of Madness in Sixteenth-Century Germany", Midelfort notes they "could not perceive the color red at all", and Bartholomew reports "it was said that dancers could not stand... the color red, often becoming violent on seeing [it]".

Bartholomew also notes that dancers "could not stand pointed shoes", and that dancers enjoyed their feet being hit. Throughout, those affected by dancing mania suffered from a variety of ailments, including chest pains, convulsions, hallucinations, hyperventilation, epileptic fits, and visions. In the end, most simply dropped down, overwhelmed with exhaustion. Midelfort, however, describes how some ended up in a state of ecstasy. Typically, the mania was contagious but it often struck small groups, such as families and individuals.

An intrusive thought is an unwelcome involuntary thought, image, or unpleasant idea that may become an obsession, is upsetting or distressing, and can feel difficult to manage or eliminate. When such thoughts are associated with obsessive-compulsive disorder (OCD), depression, body dysmorphic disorder (BDD), and sometimes attention-deficit hyperactivity disorder (ADHD), the thoughts may become paralyzing, anxiety-provoking, or persistent. Intrusive thoughts may also be associated with episodic memory, unwanted worries or memories from OCD, posttraumatic stress disorder, other anxiety disorders, eating disorders, or psychosis. Intrusive thoughts, urges, and images are of inappropriate things at inappropriate times, and generally have aggressive, sexual, or blasphemous themes.

Intrusive thoughts may involve violent obsessions about hurting others or themselves. They can be related to primarily obsessional obsessive compulsive disorder. These thoughts can include harming a child; jumping from a bridge, mountain, or the top of a tall building; urges to jump in front of a train or automobile; and urges to push another in front of a train or automobile. Rachman's survey of healthy college students found that virtually all of them had intrusive thoughts from time to time, including:

- causing harm to elderly people

- imagining or wishing harm upon someone close to oneself

- impulses to violently attack, hit, harm or kill a person, small child, or animal

- impulses to shout at or abuse someone, or attack and violently punish someone, or say something rude, inappropriate, nasty, or violent to someone.

These thoughts are part of being human, and need not ruin quality of life. Treatment is available when the thoughts are associated with OCD and become persistent, severe, or distressing.

A variant of aggressive intrusive thoughts is L'appel du vide, or the call of the void. Sufferers of "L'appel du vide" generally describe the condition as manifesting in certain situations, normally as a wish or brief desire to jump from a high location.

Symptoms for Alström syndrome generally appear during infancy with great variability in age. Some of the symptoms include:

- Heart failure (Dilated cardiomyopathy) in over 60% of cases, usually within the first few weeks after birth, but sometimes the onset is in adolescence or adulthood.

- Light sensitivity and vision problems (Cone-rod dystrophy) in all cases, usually within 15 months of birth and progressively worsening until about 20 years of age

- Delays in early, developmental milestones in 50% of cases, learning disabilities in about 30% of cases

- Obesity in 100% of cases, apparent by 5 years of age, but often apparent in infancy (Alström infants usually have normal birth weights, and by adolescence, weights tend to be in the high-normal to normal range)

- Nystagmus (usually affects the children) one of the first symptoms to occur which causes involuntary rapid eye movement.

- Heart failure (Dilated cardiomyopathy) in over 60% of cases, usually within the first few weeks after birth, but sometimes the onset is in adolescence or adulthood.(chronic)

- Mild to moderate bilateral sensorineural hearing loss.

- Type 2 diabetes usually occurs in early childhood.

- Hyperinsulinemia/ insulin resistance—development of high level of insulin in blood.

- Steatosis (fatty liver) and elevated transaminases (liver enzymes) often develop in childhood and can progress in some patients to cirrhosis and liver failure.

- Endocrine dysfunctions may occur where the patient may experience an under or over active thyroid gland, weak growth hormone, increased androgen in females, and low testosterone in males.

- Slowly progressive kidney failure can occur in the second to fourth decade of life.

A monothematic delusion is a delusional state that concerns only one particular topic. This is contrasted by what is sometimes called "multi-thematic" or "polythematic" delusions where the person has a range of delusions (typically the case of schizophrenia). These disorders can occur within the context of schizophrenia or dementia or they can occur without any other signs of mental illness. When these disorders are found outside the context of mental illness, they are often caused by organic dysfunction as a result of traumatic brain injury, stroke, or neurological illness.

People who experience these delusions as a result of organic dysfunction often do not have any obvious intellectual deficiency nor do they have any other symptoms. Additionally, a few of these people even have some awareness that their beliefs are bizarre, yet they cannot be persuaded that their beliefs are false.