List of symptoms that has been observed in those with autistic catatonia:

- Stupor

- Mutism

- Hyperactivity

- Agitation

- Excitement

- Posing

- Negativism

- Rigidity

- Waxy flexibility

- Automatic obedience

- Combativeness (during excitement)

- Aggressivity

- Stereotypies

- Tics

- Grimacing

- Echolalia

- Echopraxia

- Perseveration

- Verbigeration

- Staring

- Withdrawal

- Immobility

- Challenging behaviour

- Tremor

- Slowness

- Amotivation

- Grasp reflex

- Mannerism

- Gaze fixation

- Choreoathetoid movements of the trunk and extremities

- Autonomic instability (during excitement)

- Cannot start actions

- Cannot stop actions (if during excitement episodes needs acute psychiatric care)

- Freezing

- Impulsivity

- Bizarre/psychotic

- Sleep problems

- Urinary or Fecal incontinence

- Odd gait

- Passivity

- Reversal of day and night

- Eyerolling

- Stiff muscles

- Catalepsy

- Physiological pillow

- Difficulty crossing lines

- Gegenhalten

- Mitgehen

- Mitmachen

- Ambitendency

- Rituals

Treatment consists of high-dose lorazepam or in some cases ECT. The response to the treatment is usually good, especially if detected early

Circumstantial speech (also referred to as circumstantiality) is the result of a so called "non-linear thought pattern" and occurs when the focus of a conversation drifts, but often comes back to the point. In circumstantiality, apparently unnecessary details and seemingly irrelevant remarks cause a delay in getting to the point.

If someone exhibits circumstantial speech during a conversation, they will often seem to "talk the long way around" to their point, which may be an attempt by the speaker to include pertinent hyperspatial details, that may contrast with linear speech, which is more direct, succinct, and to the point (the gist) even at the expense of more precise, accurate communication. Some individuals with autistic tendencies may prefer highly precise speech, and this may seem circumstantial, but in fact it is a choice that posits that more details are necessary to communicate a precise meaning, and preempt more disastrous ambiguous communication.

Circumstantial speech is more direct than tangential speech in which the speaker wanders and drifts (in order to add more thought vectors in unrelated hyperplanes) and usually never returns to the original topic, and is far less severe than logorrhea. A helpful metaphor is traveling to a destination. If someone is thinking and speaking linearly, then they will go directly to the point. Circumstantial speech is more like taking "unnecessary" detours, according to some, but the speaker eventually arrives at the intended destination. In tangential speech, the speaker simply gets lost along the way, never returning to the original topic of conversation. With logorrhea, which is closer to word salad, it may not even be clear that the speaker had a particular idea or point in the first place.

A person afflicted with circumstantiality has slowed thinking and invariably talks at length about irrelevant and trivial details (i.e. circumstances). Eliciting information from such a person can be difficult since circumstantiality makes it hard for the individual to stay on topic. In most instances however, the relevant details are eventually achieved.

The disorder is often associated with schizophrenia and obsessive-compulsive disorder.

Characteristics of paroxysmal sympathetic hyperactivity include:

- fever

- tachycardia

- hypertension

- tachypnea

- hyperhidrosis or diaphoresis

- dystonic posturing

- pupillary dilation

- flushing

In cases where PSH episodes develop post-injury, specifically traumatic brain injury, symptoms typically develop quickly, usually within a week. Symptom onset has been seen to average 5.9 days post-injury. Episodes vary in duration and occurrence. Episodes can last as little as a few minutes or as long as ten hours, and they can occur multiple times a day. Episode duration has been seen to average 30.8 minutes and occur five to six times a day. Episodes can occur naturally or arise from external triggers. Common triggers include pain or stimulation, body turning or movements, and bladder distention. Bladder distention has been observed in patients being treated in intensive care units with the concurrent use of catheters. Symptoms of PSH can last from weeks to years following initial onset. As episodes persist over time, they have been found to become less frequent in occurrence but last for prolonged periods.

Waxy flexibility is a psychomotor symptom of catatonia as associated with schizophrenia, bipolar disorder, or other mental disorders which leads to a decreased response to stimuli and a tendency to remain in an immobile posture. Attempts to reposition the patient are met by "slight, even resistance", and after being repositioned the patient will typically remain in the new position. Waxy flexibility rarely occurs in cases of delirium. The presence of waxy flexibility along with at least two other catatonic symptoms such as stupor or negativism are enough to warrant a diagnosis of catatonia.

For instance, if one were to move the arm of someone with waxy flexibility, they would keep their arm where one moved it until it was moved again, as if it were made from wax. Further alteration of an individual's posture is similar to bending a candle. Although waxy flexibility has historically been linked to schizophrenia, there are also other disorders which it may be associated with, for example, mood disorder with catatonic behaviour.

Electroconvulsive therapy is often used as a treatment for catatonia. A study has found that catatonic patients suffering from waxy flexibility responded faster to electroconvulsive therapy, compared to patients with different catatonic symptoms.

People with catatonia may experience an extreme loss of motor skill or even constant hyperactive motor activity. Catatonic patients will sometimes hold rigid poses for hours and will ignore any external stimuli. People with catatonic excitement can suffer from exhaustion if not treated. Patients may also show stereotyped, repetitive movements.

They may show specific types of movement such as waxy flexibility, in which they maintain positions after being placed in them by someone else. Conversely, they may remain in a fixed position by resisting movement in proportion to the force applied by the examiner. They may repeat meaningless phrases or speak only to repeat what the examiner says.

While catatonia is only identified as a symptom of schizophrenia in present psychiatric classifications, it is increasingly recognized as a syndrome with many faces. It appears as the Kahlbaum syndrome (motionless catatonia), malignant catatonia (neuroleptic malignant syndrome, toxic serotonin syndrome), and excited forms (delirious mania, catatonic excitement, oneirophrenia).

It has also been recognized as grafted on to autism spectrum disorders.

Because these are frequently found in cases of autistic disorders, criteria could be met for multiple neurological disorders, or cause severe symptoms.

Some examples include:

1. Learning difficulties symptoms such as dyslexia, dysgraphia, dyscalcula, NVLD, slow learning, poor memory, etc.

2. AD/HD symptoms such as poor concentration, poor decision making, poor judgement, impulsiveness, difficulty sitting still, etc.

3. Synesthesia.

4. Neurological sleep disorders such as narcolepsy, insomnia, circadian rhythm disorder, etc.

5. Conditions affecting perceptions and/or cognition, such as agnosia, aphasia, etc.

6. Tourette syndrome or Tic disorder.

7. Epilepsy or Seizure disorder.

8. Parkinsonian syndrome features such as tremors, stiff movements, etc.

Catalepsy is a symptom of certain nervous disorders or conditions such as Parkinson's disease and epilepsy. It is also a characteristic symptom of cocaine withdrawal, as well as one of the features of catatonia. It can be caused by schizophrenia treatment with anti-psychotics, such as haloperidol, and by the anesthetic ketamine. Protein kinase A has been suggested as a mediator of cataleptic behavior.

Catatonia is a state of psycho-motor immobility and behavioral abnormality manifested by stupor. It was first described in 1874 by Karl Ludwig Kahlbaum, in ("Catatonia or Tension Insanity").

Though catatonia has historically been related to schizophrenia (catatonic schizophrenia), it is now known that catatonic symptoms are nonspecific and may be observed in other mental disorders and neurological conditions. In the fifth edition of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM), catatonia is not recognized as a separate disorder, but is associated with psychiatric conditions such as schizophrenia (catatonic type), bipolar disorder, post-traumatic stress disorder, depression and other mental disorders, narcolepsy, as well as drug abuse or overdose (or both). It may also be seen in many medical disorders including infections (such as encephalitis), autoimmune disorders, focal neurologic lesions (including strokes), metabolic disturbances, alcohol withdrawal and abrupt or overly rapid benzodiazepine withdrawal. In the fifth edition of the DSM, it is written that a variety of medical conditions may cause catatonia, especially neurological conditions: encephalitis, cerebrovascular disease, neoplasms, head injury. Moreover, metabolic conditions: homocystinuria, diabetic ketoacidosis, hepatic encephalopathy, hypercalcaemia.

It can be an adverse reaction to prescribed medication. It bears similarity to conditions such as encephalitis lethargica and neuroleptic malignant syndrome. There are a variety of treatments available; benzodiazepines are a first-line treatment strategy. Electroconvulsive therapy is also sometimes used. There is growing evidence for the effectiveness of NMDA receptor antagonists for benzodiazepine-resistant catatonia. Antipsychotics are sometimes employed but require caution as they can worsen symptoms and have serious adverse effects.

Other conditions which feature repetitive behaviors in the differential diagnosis include autism spectrum disorders, obsessive–compulsive disorder, tic disorders (e.g., Tourette syndrome), and other conditions including dyskinesias.

Stereotypic movement disorder is often misdiagnosed as tics or Tourette syndrome (TS). Unlike the tics of TS, which tend to appear around age six or seven, repetitive movements typically start before age three, are more bilateral than tics, and consist of intense patterns of movement for longer runs than tics. Tics are less likely to be stimulated by excitement. Children with stereotypic movement disorder do not always report being bothered by the movements as a child with tics might.

Paroxysmal sympathetic hyperactivity (PSH) is a syndrome that causes episodes of increased activity of the sympathetic nervous system. Hyperactivity of the sympathetic nervous system can manifest as increased heart rate, increased respiration, increased blood pressure, diaphoresis, and hyperthermia.

Previously, this syndrome has been identified as general dysautonomia but now is considered a specific form of it. It has also been referred to as paroxysmal sympathetic instability with dystonia, or PAID, and sympathetic storm. Recently, however, studies have adopted the name paroxysmal sympathetic hyperactivity to ensure specificity. PSH is observed more in younger patients than older ones. It is also seen more commonly in men than women. There is no known reason why this is the case, although it is suspected pathophysiological links may exist. In patients surviving traumatic brain injury, the occurrence of these episodes is one in every three. PSH can also be associated with severe anoxia, subarachnoid and intracerebral hemorrhage, and hydrocephalus.

The current diagnostic criteria for MCDD are a matter of debate due to it not being in the DSM-IV or ICD-10. Various websites contain various diagnostic criteria. At least three of the following categories should be present. Co-occurring clusters of symptoms must also not be better explained by being symptoms of another disorder such as experiencing mood swings due to autism, cognitive difficulties due to schizophrenia, and so on. The exact diagnostic criteria for MCDD remain unclear but may be a useful diagnosis for people who do not fall into any specific category. It could also be argued that MCDD is a vague and unhelpful term for these patients.

Diogenes syndrome is a disorder that involves hoarding of rubbish and severe self-neglect. In addition, the syndrome is characterized by domestic squalor, syllogomania, social alienation, and refusal of help. It has been shown that the syndrome is caused as a reaction to stress that was experienced by the patient. The time span in which the syndrome develops is undefined, though it is most accurately distinguished as a reaction to stress that occurs late in life.

In most instances, patients were observed to have an abnormal possessiveness and patterns of compilation in a disordered manner. These symptoms suggest damages on the prefrontal areas of the brain, due to its relation to decision making. Although in contrast, there have been some cases where the hoarded objects were arranged in a methodical manner, which may suggest a cause other than brain damage.

Although most patients have been observed to come from homes with poor conditions, and many had been faced with poverty for a long period of time, these similarities are not considered as a definite cause to the syndrome. Research showed that some of the participants with the condition had solid family backgrounds as well successful professional lives. Half of the patients were of higher intelligence level. This indicates the "Diogenes syndrome" does not exclusively affect those experiencing poverty or those who had traumatic childhood experiences.

The severe neglect that they bring on themselves usually results in physical collapse or mental breakdown. Most individuals who suffer from the syndrome do not get identified until they face this stage of collapse, due to their predilection to refuse help from others.

The patients are generally highly intelligent, and the personality traits that can be seen frequently in patients diagnosed with Diogenes syndrome are aggressiveness, stubbornness, suspicion of others, unpredictable mood swings, emotional instability and deformed perception of reality. Secondary DS is related to mental disorders. The direct relation of the patients' personalities to the syndrome is unclear, though the similarities in character suggest potential avenues for investigation.

Diogenes syndrome, also known as senile squalor syndrome, is a disorder characterized by extreme self-neglect, domestic squalor, social withdrawal, apathy, compulsive hoarding of garbage or animals, and lack of shame. Sufferers may also display symptoms of catatonia.

The condition was first recognized in 1966 and designated Diogenes syndrome by Clark et al. The name derives from Diogenes of Sinope, an ancient Greek philosopher, a Cynic and an ultimate minimalist, who allegedly lived in a large jar in Athens. Not only did he not hoard, but he actually sought human company by venturing daily to the Agora. Therefore, this eponym is considered to be a misnomer, but he is actually a representative existence of self-neglect. Other possible terms are "senile breakdown", "Plyushkin's Syndrome" (after a character from Gogol's novel "Dead Souls"), "social breakdown" and "senile squalor syndrome". Frontal lobe impairment may play a part in the causation (Orrell et al., 1989).

Symptoms include: rigid body, rigid limbs, limbs staying in same position when moved (waxy flexibility), no response, loss of muscle control, and slowing down of bodily functions, such as breathing.

Stereotyped movements are common in infants and young children; if the child is not distressed by movements and daily activities are not impaired, diagnosis is not warranted. When stereotyped behaviors cause significant impairment in functioning, an evaluation for stereotypic movement disorder is warranted. There are no specific tests for diagnosing this disorder, although some tests may be ordered to rule out other conditions. SMD may occur with Lesch-Nyhan syndrome, intellectual disability, and fetal alcohol exposure or as a result of amphetamine intoxication.

When diagnosing stereotypic movement disorder, DSM-5 calls for specification of:

- with or without self-injurious behavior;

- association with another known medical condition or environmental factor;

- severity (mild, moderate or severe).

CDD is a rare condition, with only 1.7 cases per 100,000.

A child affected with childhood disintegrative disorder shows normal development and he/she acquires "normal development of age-appropriate verbal and nonverbal communication, social relationships, motor, play and self-care skills" comparable to other children of the same age. However, between the ages of 2 and 10, skills acquired are lost almost completely in at least two of the following six functional areas:

- Expressive language skills (being able to produce speech and communicate a message)

- Receptive language skills (comprehension of language - listening and understanding what is communicated)

- Social skills and self care skills

- Control over bowel and bladder

- Play skills

- Motor skills

Lack of normal function or impairment also occurs in at least two of the following three areas:

- Social interaction

- Communication

- Repetitive behavior and interest patterns

In her book, "Thinking in Pictures", Temple Grandin argues that compared to "Kanner's classic autism" and to Asperger syndrome, CDD is characterized with more severe sensory processing disorder but less severe cognitive problems. She also argues that compared to most autistic people, persons with CDD have more severe speech pathology and they usually do not respond well to stimulants.

The childhood disintegrative disorder (CDD), also known as Heller's syndrome and disintegrative psychosis, is a rare condition characterized by late onset of developmental delays—or stunning reversals—in language, social function, and motor skills. Researchers have not been successful in finding a cause for the disorder. CDD has some similarity to autism, and is sometimes considered a low-functioning form of it. In May 2013, the term CDD, along with other types of autism, was fused into a single diagnostic term called "autism spectrum disorder" under the new DSM-5 manual. Therefore, CDD is now also called "regressive autism", being that this term can now refer to any type of autism spectrum disorder that involves regression, including CDD.

CDD was originally described by Austrian educator Theodor Heller (1869–1938) in 1908, 35 years before Leo Kanner and Hans Asperger described autism. Heller had previously used the name "dementia infantilis" for the syndrome.

An apparent period of fairly normal development is often noted before a regression in skills or a series of regressions in skills. The age at which this regression can occur varies, but typically after 3 years of normal development. The regression can be so dramatic that the child may be aware of it, and may in its beginning even ask, vocally, what is happening to them. Some children describe or appear to be reacting to hallucinations, but the most obvious symptom is that skills apparently attained are lost.

Many children are already somewhat delayed when the disorder becomes apparent, but these delays are not always obvious in young children. This has been described by many writers as a devastating condition, affecting both the family and the individual's future. As is the case with all pervasive developmental disorder categories, there is considerable controversy about the right treatment for CDD.

Echopraxia is a typical symptom of Tourette syndrome but causes are not well elucidated.

One theoretical cause subject to ongoing debate surrounds the role of the mirror neuron system (MNS), a group of neurons in the inferior frontal gyrus (F5 region) of the brain that may influence imitative behaviors, but no widely accepted neural or computational models have been put forward to describe how mirror neuron activity supports cognitive functions such as imitation.

Childhood schizophrenia (also known as childhood-onset schizophrenia, and very early-onset schizophrenia) is a schizophrenia spectrum disorder that is characterized by loosening of associations, delusions, catatonic behavior and "negative symptoms", such as inappropriate or blunted affect, withdrawal and schizophrenic autism, anhedonia with onset before 13 years of age. The term "childhood-onset schizophrenia" and "very early-onset schizophrenia" are used to identify patients in whom the disorder manifests before the age of 13.

The disorder presents symptoms such as auditory and visual hallucinations, strange thoughts or feelings, and abnormal behavior, profoundly impacting the child's ability to function and sustain normal interpersonal relationships. Delusions are often not systematized and vague.. Among the actual psychotic symptoms seen in childhood schizophrenia auditory hallucinations are the most common. They are often presented in relatively simple form of akoasms (auditory hallucinations, such as noise, shots, knocks, etc.). It typically presents after the age of seven. About 50% of young children diagnosed with schizophrenia experience severe neuropsychiatric symptoms. Studies have demonstrated that diagnostic criteria are similar to those of adult schizophrenia. Diagnosis is based on behavior observed by caretakers and, in some cases depending on age, self reports.

Schizophrenia has no definite cause; however, certain risk factors such as family history seem to correlate. There is no known cure, but childhood schizophrenia is controllable with the help of behavioral therapies and medications.

There is no formal test for diagnosing echopraxia. It is easier to distinguish in individuals over the age of five, because younger children frequently imitate others' actions.

Imitation can be divided into two types: imitative learning and automatic imitation. Imitative learning occurs when a person consciously mimics an observed action in order to learn the mechanism behind that action and perform it himself or herself. Babies begin copying movements soon after birth; this behavior begins to diminish around the age of three. Before that, it is not possible to diagnose echopraxia, because it is difficult to differentiate between imitative learning and automatic imitation. If the imitative behavior continues beyond infanthood, it may be considered echopraxia.

Echopraxia may be more easily distinguished in older individuals, because their behaviors in relation to prior behaviors can be differentiated. They report feeling an uncontrollable urge to perform an action after seeing it being performed. Automatic behavior is occasionally present in healthy adults (for example, when a person observes someone yawning, he or she may do the same); these behaviors are not considered echopraxia.

The first symptoms of neuroleptic malignant syndrome are usually muscle cramps and tremors, fever, symptoms of autonomic nervous system instability such as unstable blood pressure, and sudden changes in mental status (agitation, delirium, or coma). Once symptoms appear, they may progress rapidly and reach peak intensity in as little as three days. These symptoms can last anywhere from eight hours to forty days.

Symptoms are sometimes misinterpreted by doctors as symptoms of mental illness which can result in delayed treatment. NMS is less likely if a person has previously been stable for a period of time on antipsychotics, especially in situations where the dose has not been changed and there are no issues of noncompliance or consumption of psychoactive substances known to worsen psychosis.

- Increased body temperature >38 °C (>100.4 °F), or

- Confused or altered consciousness

- sweating

- Rigid muscles

- Autonomic imbalance

Schizophrenia is a mental disorder that is expressed in abnormal mental functions and disturbed behavior.

The signs and symptoms of childhood schizophrenia are nearly the same as adult-onset schizophrenia. Some of the earliest signs that a young child may develop schizophrenia are lags in language and motor development. Some children engage in activities such as flapping the arms or rocking, and may appear anxious, confused, or disruptive on a regular basis. Children may experience symptoms such as hallucinations, but these are often difficult to differentiate from just normal imagination or child play. It is often difficult for children to describe their hallucinations or delusions, making very early-onset schizophrenia especially difficult to diagnose in the earliest stages. The cognitive abilities of children with schizophrenia may also often be lacking, with 20% of patients showing borderline or full intellectual disability.

Very early-onset schizophrenia refers to onset before the age of thirteen. The prodromal phase, which precedes psychotic symptoms, is characterized by deterioration in school performance, social withdrawal, disorganized or unusual behavior, a decreased ability to perform daily activities, a deterioration in self-care skills, bizarre hygiene and eating behaviors, changes in affect, a lack of impulse control, hostility and aggression, and lethargy.

Auditory hallucinations are the most common "positive symptom" in children. Positive symptoms have come to mean psychopathological disorders that are actively expressed, such as delusions, hallucinations, thought disorder etc.). A child's auditory hallucinations may include voices that are conversing with each other or voices that are speaking directly to the children themselves. Many children with auditory hallucinations believe that if they do not listen to the voices, the voices will harm them or someone else. Tactile and visual hallucinations seem relatively rare. The children often attribute the hallucinatory voices to a variety of beings, including family members or other people, evil forces ("the Devil", "a witch", "a spirit"), animals, characters from horror movies (Bloody Mary, Freddy Krueger) and less clearly recognizable sources ("bad things," "the whispers"). Command auditory hallucinations (also known as imperative hallucinations) were common and experienced by more than ½ of the group in a research at the Bellevue Hospital Center's Children's Psychiatric Inpatient Unit. And voices repeat and repeat: "Kill somebody!", "Kill her, kill her!". Delusions are reported in more than half of children with schizophrenia, but they are usually less complex than those of adults. Delusions often connected with hallucinatory experiences.. In a research delusions were characterized as persecutory for the most part, but some children reported delusions of control. Many said they were being tortured by the beings causing their visual and auditory hallucinations, some thought that if they disobeying their voices would cause them harm.

Some degree of thought disorder was observed in a test group of children in Bellevue Hospital. They displayed illogicality, tangentialiry (a serious disturbance in the associative thought process), and loosening of associations.

Negative ("deficit") symptoms in schizophrenia reflect mental deficit states such as apathy and aboulia, avolition, flattened affect, asthenia etc.

Sensory-based motor disorder shows motor output that is disorganized as a result of incorrect processing of sensory information affecting postural control challenges, resulting in postural disorder, or developmental coordination disorder.

The SBMD subtypes are:

1. Dyspraxia

2. Postural disorder