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.

The onset of Latah is often associated with stress. In a study done by Tanner and Chamberland in 2001, a significant number of research participants had experienced a life stressor (such as a child or husband dying) just before becoming latah. Additionally, a large number of participants from many research studies have reported strange dreams occurring just before the onset of latah. These dreams usually had a sexual element to them, often involving penises or enlarged penises. According to Tanner and Chamberland, perhaps the dreams, although with variation, indicate some sort of dysfunction in a specific anatomical area. Exploring this further might lead to more insights as to the cause and/or cure of latah.

Osborne (2001) states that latah is a possible emotional outlet in a stifling culture. Winzeler’s believes that latah is less demeaning for women than it is for men, and that women actually have more freedom in society because they are not held to as strict of standards as men are. He argues that as men age, they become more concerned with personal dignity and poise while women become less so. Because of this, women feel more freedom to engage in latah behavior, while men do not.

Running amok, sometimes referred to as simply amok or gone amok, also spelled amuk, from the Malay language, is "an episode of sudden mass assault against people or objects usually by a single individual following a period of brooding that has traditionally been regarded as occurring especially in Malay culture but is now increasingly viewed as psychopathological behavior". The syndrome of "Amok" is found in the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV TR). The phrase is often used in a less serious manner when describing something that is wildly out of control or causing a frenzy (e.g., a dog tearing up the living room furniture might be termed as "running amok".)

In 1849, amok was officially classified as a psychiatric condition based on numerous reports and case studies that showed the majority of individuals who committed amok were, in some sense, mentally ill. The modern DSM-IV method of classification of mental disorders contains two official types of amok disorder; beramok and amok. Beramok is considered to be the more common of the two and is associated with the depression and sadness resulting from a loss and the subsequent brooding process. Loss includes, but is not limited to, the death of a spouse or loved one, divorce, loss of a job, money, power, etc. Beramok is associated with mental issues of severe depression or other mood disorders. Amok, the rarer form, is believed to stem from rage, insult, or a vendetta against a person, society, or object for a wide variety of reasons. Amok has been more closely associated with psychosis, personality disorders, bipolar disorder, and delusions.

The cause of Jumping Frenchmen syndrome is unknown. One theory is that it is a genetic condition. Observation of 50 cases found the disorder to be remotely located and concentrated in the northern regions of Maine. Fourteen of these cases were found in four families. Another set of cases were found in a single family where the father, his two sons, and his two grandchildren exhibited "jumping" behavior.

It may also be a culture-bound syndrome or a formed habit. These French "jumpers" lived in a very remote region and most were lumberjacks. This type of small community would allow for a majority to adapt to this sort of reaction. Also, instances of many being shy may imply that the "jumper" was positively reinforced by the sudden attention as the entertainment for a group.

In 1885, Georges Gilles de la Tourette included Jumping Frenchmen syndrome in the typology of "convulsive tic illness"; studies of the condition in the 1980s cast doubt on whether the phenomenon was in fact a physical condition similar to Tourette syndrome. Documentation of direct observation of "Jumping Frenchmen" has been scarce, and while videotape evidence was recorded by several researchers that showed the condition to be real, MH and JM Saint-Hilaire concluded from studying eight affected people that it was brought on by conditions at their lumber camps and was psychological, not neurological.

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.

Brief psychotic disorder is a period of psychosis whose duration is generally shorter, is not always non-recurring, but can be, and is not caused by another condition.

Echopraxia (also known as echokinesis) is the involuntary repetition or imitation of another person's actions. Similar to echolalia, the involuntary repetition of sounds and language, it is one of the echophenomena ("automatic imitative actions without explicit awareness"). It has long been recognized as a core feature of Tourette syndrome, and is considered a complex tic, but it also occurs in autism spectrum disorders, schizophrenia and catatonia, aphasia, and disorders involving the startle reflex such as Latah. Echopraxia has also been observed in individuals with frontal lobe damage, epilepsy, dementia and autoimmune disorders; the causes of and the link between echopraxia and these disorders is undetermined.

The etymology of the term is from Ancient Greek: " (ēkhō) from (ēkhē "sound") and " (praksis, "action, activity, practice)".

The disorder is characterized by a sudden onset of psychotic symptoms, which may include delusions, hallucinations, disorganized speech or behavior, or catatonic behavior. The symptoms must not be caused by schizophrenia, schizoaffective disorder, delusional disorder or mania in bipolar disorder. They must also not be caused by a drug (such as amphetamines) or medical condition (such as a brain tumor). The term bouffée délirante describes an acute nonaffective and nonschizophrenic psychotic disorder, which is largely similar to DSM-III-R and DSM-IV brief psychotic and schizophreniform disorders.

Symptoms generally last at least a day, but not more than a month, and there is an eventual return to full baseline functioning. It may occur in response to a significant stressor in one's life, or in other situations where a stressor is not apparent, including in the weeks following birth. In diagnosis, a careful distinction is considered for culturally appropriate behaviors, such as religious beliefs and activities. It is believed to be connected to or synonymous with a variety of culture-specific phenomena such as latah, koro, and amok.

There are three forms of brief psychotic disorder:

1. Brief psychotic disorder with a stressor, such as a trauma or death in the family.

2. Brief psychotic disorder without a stressor, there is no obvious stressor.

3. Brief psychotic disorder with postpartum onset. Usually occurs about four weeks after giving birth.

Echopraxia is the involuntary mirroring of an observed action. Imitated actions can range from simple motor tasks such as picking up a phone to violent actions such as hitting another person.

Imitative learning and emulation of physical and verbal actions are critical to early development (up to the age of two or three), but when these behaviors become reactions rather than a means for learning, they are considered echophenomena (copying behaviors).