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.

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).

Tics are movements or sounds "that occur intermittently and unpredictably out of a background of normal motor activity", having the appearance of "normal behaviors gone wrong". The tics associated with Tourette's change in number, frequency, severity and anatomical location. Waxing and waning—the ongoing increase and decrease in severity and frequency of tics—occurs differently in each individual. Tics may also occur in "bouts of bouts", which vary for each person.

Coprolalia (the spontaneous utterance of socially objectionable or taboo words or phrases) is the most publicized symptom of Tourette's, but it is not required for a diagnosis of Tourette's and only about 10% of Tourette's patients exhibit it. Echolalia (repeating the words of others) and palilalia (repeating one's own words) occur in a minority of cases, while the most common initial motor and vocal tics are, respectively, eye blinking and throat clearing.

In contrast to the abnormal movements of other movement disorders (for example, choreas, dystonias, myoclonus, and dyskinesias), the tics of Tourette's are temporarily suppressible, nonrhythmic, and often preceded by an unwanted premonitory urge. Immediately preceding tic onset, most individuals with Tourette's are aware of an urge, similar to the need to sneeze or scratch an itch. Individuals describe the need to tic as a buildup of tension, pressure, or energy which they consciously choose to release, as if they "had to do it" to relieve the sensation or until it feels "just right". Examples of the premonitory urge are the feeling of having something in one's throat, or a localized discomfort in the shoulders, leading to the need to clear one's throat or shrug the shoulders. The actual tic may be felt as relieving this tension or sensation, similar to scratching an itch. Another example is blinking to relieve an uncomfortable sensation in the eye. These urges and sensations, preceding the expression of the movement or vocalization as a tic, are referred to as "premonitory sensory phenomena" or premonitory urges. Because of the urges that precede them, tics are described as semi-voluntary or ""unvoluntary"", rather than specifically "involuntary"; they may be experienced as a "voluntary", suppressible response to the unwanted premonitory urge. Published descriptions of the tics of Tourette's identify sensory phenomena as the core symptom of the syndrome, even though they are not included in the diagnostic criteria.

While individuals with tics are sometimes able to suppress their tics for limited periods of time, doing so often results in tension or mental exhaustion. People with Tourette's may seek a secluded spot to release their symptoms, or there may be a marked increase in tics after a period of suppression at school or at work. Some people with Tourette's may not be aware of the premonitory urge. Children may be less aware of the premonitory urge associated with tics than are adults, but their awareness tends to increase with maturity. They may have tics for several years before becoming aware of premonitory urges. Children may suppress tics while in the doctor's office, so they may need to be observed while they are not aware they are being watched. The ability to suppress tics varies among individuals, and may be more developed in adults than children.

Although there is no such thing as a "typical" case of Tourette syndrome, the condition follows a fairly reliable course in terms of the age of onset and the history of the severity of symptoms. Tics may appear up to the age of eighteen, but the most typical age of onset is from five to seven. A 1998 study published by Leckman and colleagues from the Yale Child Study Center showed that the ages of highest tic severity are eight to twelve (average ten), with tics steadily declining for most patients as they pass through adolescence. The most common, first-presenting tics are eye blinking, facial movements, sniffing and throat clearing. Initial tics present most frequently in midline body regions where there are many muscles, usually the head, neck and facial region. This can be contrasted with the stereotyped movements of other disorders (such as stims and stereotypies of the autism spectrum disorders), which typically have an earlier age of onset, are more symmetrical, rhythmical and bilateral, and involve the extremities (e.g., flapping the hands). Tics that appear early in the course of the condition are frequently confused with other conditions, such as allergies, asthma, and vision problems: pediatricians, allergists and ophthalmologists are typically the first to see a child with tics.

Most cases of Tourette's in older individuals are mild and almost unrecognizable. When symptoms are severe enough to warrant referral to clinics, obsessive–compulsive disorder (OCD) and attention-deficit hyperactivity disorder (ADHD) are often associated with Tourette's. In children with tics, the additional presence of ADHD is associated with functional impairment, disruptive behavior, and tic severity. Compulsions resembling tics are present in some individuals with OCD; "tic-related OCD" is hypothesized to be a subgroup of OCD, distinguished from non-tic related OCD by the type and nature of obsessions and compulsions. Not all persons with Tourette's have ADHD or OCD or other comorbid conditions, although in clinical populations, a high percentage of patients presenting for care do have ADHD. One author reports that a ten-year overview of patient records revealed about 40% of patients with Tourette's have "TS-only" or "pure TS", referring to Tourette syndrome in the absence of ADHD, OCD and other disorders. Another author reports that 57% of 656 patients presenting with tic disorders had uncomplicated tics, while 43% had tics plus comorbid conditions. People with "full-blown Tourette's" have significant comorbid conditions in addition to tics.

Tics are sudden, repetitive, nonrhythmic movements (motor tics) and utterances (phonic tics) that involve discrete muscle groups. Motor tics are movement-based tics, while phonic tics are involuntary sounds produced by moving air through the nose, mouth, or throat.

Tourette's was classified by the fourth version of the "Diagnostic and Statistical Manual of Mental Disorders" (DSM-IV-TR) as one of several tic disorders "usually first diagnosed in infancy, childhood, or adolescence" according to type (motor or phonic tics) and duration (transient or chronic). Transient tic disorders consisted of multiple motor tics, phonic tics or both, with a duration between four weeks and twelve months. Chronic tic disorder was either single or multiple, motor or phonic tics (but not both), which were present for more than a year. Tourette's is diagnosed when multiple motor tics, and at least one phonic tic, are present for more than a year. The fifth version of the DSM (DSM-5), published in May 2013, reclassified Tourette's and tic disorders as motor disorders listed in the neurodevelopmental disorder category, and replaced transient tic disorder with provisional tic disorder, but made few other significant changes.

Tic disorders are defined only slightly differently by the World Health Organization International Statistical Classification of Diseases and Related Health Problems, ICD-10; code F95.2 is for combined vocal and multiple motor tic disorder [de la Tourette].

Although Tourette's is the more severe expression of the spectrum of tic disorders, most cases are mild. The severity of symptoms varies widely among people with Tourette's, and mild cases may be undetected.

ICD10 diagnosis codes are:

- F95.0 Transient tic disorder

- F95.1 Chronic motor or vocal tic disorder

- F95.2 Combined vocal and multiple motor tic disorder [Gilles de la Tourette]

- F95.8 Other tic disorders

- F95.9 Tic disorder, unspecified

In the fourth revision of the DSM (DSM-IV-TR), tic disorders were classified as follows:

- Transient tic disorder consisted of multiple motor and/or phonic tics with duration of at least 4 weeks, but less than 12 months.

- Chronic tic disorder was either single or multiple motor or phonic tics, but not both, which were present for more than a year.

- Tourette syndrome was diagnosed when both motor and phonic tics were present for more than a year.

- Tic disorder NOS was diagnosed when tics were present, but did not meet the criteria for any specific tic disorder.

Like tics, stereotypies are patterned and periodic, and are made worse by fatigue, stress, and anxiety. Unlike tics, stereotypies usually begin before the age of three, involve more of the body, are more rhythmic and less random, and are associated more with engrossment in another activity rather than premonitory urges. Examples of early tics are things like blinking and throat clearing, while arm flapping is a more common stereotypy. Stereotypies do not have the ever-changing, waxing and waning nature of tics, and can remain constant for years. Tics are usually suppressible for brief periods; in contrast, children rarely consciously attempt to control a stereotypy, although they can be distracted from one.

There are several possible explanations for stereotypy, and different stereotyped behaviors may have different explanations. A popular explanation is stimming, which hypothesizes that a particular stereotyped behavior has a function related to sensory input. Other explanations include hypotheses that stereotypy discharges tension or expresses frustration, that it communicates a need for attention or reinforcement or sensory stimulation, that it is learned or neuropathological or some combination of the two, or that it is normal behavior with no particular explanation needed.

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.

It is common for individuals with PDD-NOS to have more intact social skills and a lower level of intellectual deficit than individuals with other PDDs. Characteristics of many individuals with PDD-NOS are:

- Communication difficulties (e.g., using and understanding language)

- Difficulty with social behavior

- Difficulty with changes in routines or environments

- Uneven skill development (strengths in some areas and delays in others)

- Unusual play with toys and other objects

- Repetitive body movements or behavior patterns

- Preoccupation with fantasy, such as imaginary friends in childhood

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.

Symptoms of PDD may include behavioral and communication problems such as:

- Difficulty using and understanding language.

- Difficulty relating to people, objects, and events; for example, lack of eye contact, pointing behavior, and lack of facial responses.

- Unusual play with toys and other objects.

- Difficulty with changes in routine or familiar surroundings.

- Repetitive body movements or behavior patterns, such as hand flapping, hair twirling, foot tapping, or more complex movements.

- Inability to cuddle or be comforted.

- Difficulty regulating behaviors and emotions, which may result in temper tantrums, anxiety, and aggression.

- Emotional breakdowns.

Developmental disorders comprise a group of psychiatric conditions originating in childhood that involve serious impairment in different areas. There are several ways of using this term. The most narrow concept is used in the category "Specific Disorders of Psychological Development" in the ICD-10. These disorders comprise language disorders, learning disorders, motor disorders and autism spectrum disorders. In broader definitions ADHD is included, and the term used is neurodevelopmental disorders. Yet others include antisocial behavior and schizophrenia that begins in childhood and continues through life. However, these two latter conditions are not as stable as the other developmental disorders, and there is not the same evidence of a shared genetic liability.

Developmental disorders are present from early life. They usually improve as the child grows older, but they also entail impairments that continue through adult life. There is a strong genetic component, and more males are afflicted than females.

Children with PDD vary widely in abilities, intelligence, and behaviors. Some children do not speak at all, others speak in limited phrases or conversations, and some have relatively normal language development. Repetitive play skills and limited social skills are generally evident as well. Unusual responses to sensory information – loud noises, lights – they also are common.

Still a lot of information is unclear about ASD and the symptoms have a wide range of severity. Signs include impairments in social interactions, communication and repetitive or restricted patterns of interest or behaviors. There are also different symptoms at different ages based on developmental milestones. Children between 0 and 36 months with ASD show a lack of eye contact, seem to be deaf, lack a social smile, do not like being touched or held, have unusual sensory behavior and show a lack of imitation. Children between 12 and 24 months with ASD show a lack of gestures, prefer to be alone, do not point to objects to indicate interest, are easily frustrated with challenges, and lack of functional play. And finally children between the ages 24 to 36 months with ASD show a lack of symbolic play and an unusual interest in certain objects, or moving objects.

A pervasive developmental disorder not otherwise specified (PDD-NOS) is one of the four autism spectrum disorders (ASD) and also one of the five disorders classified as a pervasive developmental disorder (PDD). According to the DSM-IV, PDD-NOS is a diagnosis that is used for "severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present, but the criteria are not met for a specific PDD" or for several other disorders. PDD-NOS is often called atypical autism, because the criteria for autistic disorder are not met, for instance because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these. Even though PDD-NOS is considered milder than typical autism, this is not always true. While some characteristics may be milder, others may be more severe.

A tic can be defined as a repeated, individually recognizable, intermittent movement or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. These abnormal movements occur with intervening periods of normal movement. These movements are predictable, often triggered by stress, excitement, suggestion, or brief voluntary suppressibility. Many children say that the onset of tics can stem from the strong urge to move. Tics can be either muscular (alter normal motor function) or vocal (alter normal speech) in nature and most commonly involve the face, mouth, eyes, head, neck or shoulder muscles. Tics can also be classified as simple motor tics (a single brief stereotyped movement or movement fragment), complex motor tics (a more complex or sequential movement involving multiple muscle

groups), or phonic tics (including simple, brief phonations or vocalizations).

When both motor and vocal tics are present and persist for more than one year, a diagnosis of Tourette syndrome (TS) is likely. TS is an inherited neurobehavioral disorder characterized by both motor and vocal tics. Many individuals with TS may also develop obsessions, compulsions, inattention and hyperactivity. TS usually begins in childhood. Up to 5% of the population suffers from tics, but at least 20% of boys will have developed tics at some point in their lifetimes.

Stereotypies are repetitive, rhythmic, simple movements that can be voluntarily suppressed. Like tremors, they are typically back and forth movements, and most commonly occur bilaterally. They often involve fingers, wrists, or proximal portions of the upper extremities. Although, like tics, they can stem from stress and excitement, there is no underlying urge to move associated with stereotypies and these movements can be stopped with distraction. When aware of the movements, the child can also suppress them voluntarily. Stereotypies are often associated with developmental syndromes, including the autism spectrum disorders. Stereotypies are quite common in preschool-aged children and for this reason are not necessarily indicative of neurological pathology on their own.

Tourette’s syndrome is a neurological disorder characterized by recurrent involuntary movements (motor tics) and involuntary noises (vocal tics). The reason Tourette’s syndrome and other tic disorders are being considered for placement in the obsessive compulsive spectrum is because of the phenomenology and co-morbidity of the disorders with obsessive compulsive disorder. Within the population of patients with OCD up to 40% have a history of a tic disorder and 60% of people with Tourette’s syndrome have obsessions and/or compulsions. Plus 30% of people with Tourette’s syndrome have full-scale OCD. Course of illness is another factor that suggests correlation because it has been found that tics displayed in childhood are a predictor of obsessive and compulsive symptoms in late adolescence and early adulthood. However, the association of Tourette’s and tic disorders with OCD is challenged by neuropsychology and pharmaceutical treatment. Whereas OCD is treated with SSRI’s, tics are treated with dopamine blockers and alpha-2 agonists.

Tardive dyskinesia is characterized by repetitive, involuntary movements. Some examples of these types of involuntary movements include:

- Grimacing

- Tongue movements

- Lip smacking

- Lip puckering

- Pursing of the lips

- Excessive eye blinking

Rapid, involuntary movements of the limbs, torso, and fingers may also occur. In some cases, an individual's legs can be so affected that walking becomes difficult or impossible. These symptoms are the opposite of patients who are diagnosed with Parkinson's disease. Parkinson's patients have difficulty moving, whereas tardive dyskinesia patients have difficulty not moving.

Respiratory irregularity, such as grunting and difficulty breathing, is another symptom associated with tardive dyskinesia, although studies have shown that the prevalence rate is relatively low.

Tardive dyskinesia is often misdiagnosed as a mental illness rather than a neurological disorder, and as a result patients are prescribed neuroleptic drugs, which increase the probability that the patient will develop a severe and disabling case, and shortening the typical survival period.

Other closely related neurological disorders have been recognized as variants of tardive dyskinesia. Tardive dystonia is similar to standard dystonia but permanent. Tardive akathisia involves painful feelings of inner tension and anxiety and a compulsive drive to move the body. In some extreme cases, afflicted individuals experience so much internal torture that they lose their ability to sit still. Tardive tourettism is a tic disorder featuring the same symptoms as Tourette syndrome. The two disorders are extremely close in nature and often can only be differentiated by the details of their respective onsets. Tardive myoclonus, a rare disorder, presents as brief jerks of muscles in the face, neck, trunk, and extremities.

"AIMS Examination": This test is used when psychotropic medications have been prescribed because patients sometimes develop tardive dyskinesia due to prolonged use of antipsychotic medications. The Abnormal Involuntary Movement Scale (AIMS) examination is a test used to identify the symptoms of tardive dyskinesia (TD). The test is not meant to tell whether there is an absence or presence of tardive dyskinesia. It just scales to level of symptoms indicated by the actions observed. The levels range from none to severe. The AIMS examination was constructed in the 1970s to measure involuntary facial, trunk, and limb movements. It is best to do this test before and after the administration of the psychotropic drugs. Taking the AIMS consistently can help to track severity of TD over time.

Hypochondriasis is excessive preoccupancy or worry about having a serious illness. These thoughts cause a person a great deal of anxiety and stress. The prevalence of this disorder is the same for men and women. Hypochondriasis is normally recognized in early adult age. Those that suffer with hypochondriasis are constantly thinking of their body functions, minor bumps and bruises as well as body images. Hypochondriacs go to numerous outpatient facilities for confirmation of their own diagnosis. Hypochondriasis is the belief that something is wrong but it is not known to be a delusion.

This is an ill-defined disorder of uncertain nosological validity. The category is included here because of the evidence that children with moderate to severe intellectual disability (IQ below 35) who exhibit major problems in hyperactivity and inattention frequently show stereotyped behaviours; such children tend not to benefit from stimulant drugs (unlike those with an IQ in the normal range) and may exhibit a severe dysphoric reaction (sometimes with psychomotor retardation) when given stimulants; in adolescence the overactivity tends to be replaced by underactivity (a pattern that is not usual in hyperkinetic children with normal intelligence). It is also common for the syndrome to be associated with a variety of developmental delays, either specific or global. The extent to which the behavioural pattern is a function of low IQ or of organic brain damage is not known, neither is it clear whether the disorders in children with mild intellectual disability who show the hyperkinetic syndrome would be better classified here or under F90.- (Hyperkinetic disorders); at present they are included in F90-.

Diagnostic guidelines

Diagnosis depends on the combination of developmentally inappropriate severe overactivity, motor stereotypies, and moderate to severe intellectual disability; all three must be present for the diagnosis. If the diagnostic criteria for F84.0 (childhood autism), F84.1 (atypical autism) or F84.2 (Rett's syndrome) are met, that condition should be diagnosed instead.

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".

Autistic individuals can display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows.

- Stereotyped behaviors: Repetitive movements, such as hand flapping, head rolling, or body rocking.

- Compulsive behaviors: Time-consuming behaviors intended to reduce anxiety that an individual feels compelled to perform repeatedly or according to rigid rules, such as placing objects in a specific order, checking things, or hand washing.

- Sameness: Resistance to change; for example, insisting that the furniture not be moved or refusing to be interrupted.

- Ritualistic behavior: Unvarying pattern of daily activities, such as an unchanging menu or a dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.

- Restricted interests: Interests or fixations that are abnormal in theme or intensity of focus, such as preoccupation with a single television program, toy, or game.

- Self-injury: Behaviors such as eye-poking, skin-picking, hand-biting and head-banging.

No single repetitive or self-injurious behavior seems to be specific to autism, but autism appears to have an elevated pattern of occurrence and severity of these behaviors.

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.