Note: Tic disorders are hierarchical. Following the hierarchy of Tourette syndrome > chronic/persistent tic disorder > transient/provisional tic disorder, once a tic disorder at one level of the hierarchy is diagnosed a lower hierarchy diagnosis cannot be made.
Multiple tics do not have to be present at the time of diagnosis, or have existed simultaneously.
If only motor tics or only phonic tics have been experienced, the patient should be screened for chronic motor or phonic tic disorder / persistent motor or vocal tic disorder.
If tics have been experienced for less than 1 year, the patient should be screened for provisional tic disorder / transient tics.
If both motor tics and phonic tics have been experienced, the patient should be screened for Tourette syndrome.
If tics have been experienced for less than 1 year, the patient should be screened for transient motor tics.
ICD-11: "Transient motor or phonic tics are common during childhood and are differentiated [...] by their transient nature."
Tic disorders caused by outside sources such as infections, drugs, or illness are referred to as secondary tic disorders.
(World Health Organization, 2022)This may include infectious/postinfectious tics such as PANS/PANDAS.
Stereotypies (stims) associated with or not associated with ASD may be mistaken tics.
(World Health Organization, 2022)Stereotypies are functional - they have the purpose of soothing, relaxing, or stimulating.
Stereotypies are voluntary (although often unconscious) - they can be interrupted with distraction.
Stereotypies are stereotyped - they appear more patterned (rhythmic) and coördinated than tics.
Stereotypies tend to first appear at a younger age than tics, usually before age 2 or 3.
Stereotypies tend to have a longer duration than most tics.
Stereotypies are not preceded by a premonitory sensory urge.
Compulsions associated with OCD may be mistaken for tics.
(World Health Organization, 2022)Compulsions are performed in response to an obsession (a persistent unwanted thought or urge) or anxiety.
Tics are performed in response to a premonitory sensory urge, or rarely without any precursory sensation.
Compulsions may appear intentional or purposeful, even if this apparent purpose has nothing to do with the associated thoughts or anxiety.
Tics generally appear to be natural and unintentional actions.
Compulsions are not limited to discrete muscle groups.
Simple tics are limited to one discrete muscle group.
Myoclonus associated with myoclonic disorders may be mistaken for tics.
(Jankovic, 2015)Myoclonus are not preceded by a premonitory sensory urge.
Myoclonic disorders do not coöccur as commonly with disorders associated with tic disorders (eg. ADHD or OCD).
Myoclonus have a different root cause than tics do, so they do not respond to the same treatments.
Rapid-onset functional tic-like behaviors may be mistaken for tics.
(Coffman & Quezada, 2021)See below.
FNSD is a disorder characterized by neurological symptoms that are not consistent with neurological or medical conditions.
(World Health Organization, 2022)FNSD may result in a sudden-onset of tic-like behaviors, often referred to as "functional tic-like behaviors/phenomena."
FNSD typically has a sudden and intense (acute) onset between puberty and early adulthood.
FNSD may be temporary (transient) or long-lasting (persistent).
FNSD symptoms may be brief, possibly lasting only a few weeks, but commonly reappear.
FNSD frequently onsets after trauma or periods of high stress.
FND Guide
FND Hope
University of Calgary: The Tourette OCD Alberta Network
Tic disorders.
Tourette syndrome (TS).
Chronic motor tic disorder.
Chronic phonic/vocal tic disorder.
Dissociative neurological symptom disorder (in the ICD-11)
Functional neurological [symptom] disorder (FNSD/FND) (in the DSM-5)
[Rapid-onset] functional tic-like behaviors/phenomena.
Functional jerks/vocalizations.
Functional tics (misleading).
TikTok tics (misleading).
Conversion disorder (antiquated).
Tics begin in childhood.
Motor tics onset between ages 3-8.
Phonic tics onset between ages 8-15.
Onset rarely occurs after 18 years old.
One study supports onset after 18.
Functional tic-like behaviors begin between puberty and early adulthood (World Health Organization, 2022).
Conversely, this is when tic disorders begin to weaken.
Tics are very common.
Around 1% of the world population.
Functional tic-like behaviors are less common.
Around 0.0001% of the world population (National Institute of Neurological Disorders and Stroke, 2021).
Tics are more common in males.
At a ratio of 3:1 or 4:1.
Functional tic-like behaviors are more common in females.
At a ratio of 9:1.
87% of tic patients have at least one coöccuring condition (Eapen et al., 2016).
ADHD is extremely common (50-60%).
OCD is very common (20-30%).
Traits/behaviors of OCD are extremely common (66%) (Robakis, 2017).
Anxiety is very common (20-30%).
Intermittent explosive disorder is common (unknown percent).
There is a strong and well-documented relationship between TS and ADHD/OCD.
To the degree that ADHD or OCD is always seen present in either the patient or their family.
Functional tic-like behaviors are not tied with the same conditions.
ADHD is uncommon.
OCD is uncommon.
Anxiety is extremely common (far more common than with tic disorders).
Depression is extremely common (>50%).
Functional tic-like behaviors may be experienced alongside other symptoms of FND.
Symptoms of FND mimic neurological symptoms, like tics, strokes, etc.
Tics onset and progress very slowly
Tics develop and progress over the course of months or years.
Tics tend to start simple, often inconspicuous or natural, movements.
Tics usually (75%) significantly improve through adolescence.
Generally around 17.4 years old (13.6-21.1 years old).
1/3 of patients no longer experience tics in adulthood.
Adolescence is when functional tic-like behaviors usually onset.
Functional tic-like behaviors onset very suddenly (World Health Organization, 2022).
Tics develop and progress over the course of hours or days.
Functional tic-like behaviors may come and go, or may be persistent (World Health Organization, 2022).
Functional tic-like behaviors often have a brief duration, but commonly recur (World Health Organization, 2022).
Tics are predominately located in the head, face, and neck.
This is physically visible in MRI scans.
Even when tics occur in other locations, the typically began here.
Functional tic-like behaviors do not follow a consistent location pattern (Quezada et al., 2021).
Because they mimic tic symptoms they may occur in whatever locations the patient has seen tics occur or expects tics to occur.
Simple motor tics:
Eye blinking, face twitching, grimacing, shrugging, neck jerking, abdomen tensing.
Complex motor tics:
Gesturing, jumping, touching, pressing, stomping, contorting, licking, smelling, squatting, retracing steps, twirling, dystonic tics, blocking tics.
Self-injurious tics are extremely rare.
Tics are almost always natural movements.
They would not seem unusual if done less frequently or intensely.
Echopraxia (mimicking the movements of others) is very common with FNSD.
Related ideas are discussed below in the suggestibility section.
Echopraxia is present, but far more rare in tic disorders.
Simple phonic tics:
Sniffing, snorting, throat clearing, yipping, yelping, grunting, humming, coughing, spitting, barking.
Complex phonic tics (rare):
Spontaneous expression of words, palilalia, echolalia.
Tics are almost always natural vocalizations or sounds.
They would not seem unusual if done less frequently or intensely.
Coprolalia is very common with FNSD.
Coprolalia is present, but much more rare in tic disorders.
Coprolalia (profane/inappropriate vocalizations).
Developed in 15-20% of patients
Develops only after years of having severe tics.
Copropraxia (profane/inappropriate gestures).
Developed in 5-6% of patients.
Echopraxia (mimicking movements).
Too uncommon to find an accurate percent of occurrence.
Paligraphia (repetitive writing).
Tics can be made worse by stimulus that affects the body.
Eg. stress, excitement, fatigue, illness.
Functional tic-like behaviors may be made worse by any stimulus.
Eg. hunger, tiredness, boredom, etc.
Premonitory sensory urge: the building, unpleasant, itch-like sensation that precedes a tic.
Premonitory sensory urges are a hallmark feature of tics.
They are almost always present (>90%) (Reese et al., 2014).
Functional tic-like behavior patients describe their 'urge' as more of a building anxiety.
As opposed to an urge to perform a specific movement.
Any movement or noise releases this tension and feels good.
Alternatively, functional tics may happen without any urge or intention at all.
Tics are consistent and become predictable with experience.
A patient will know what tics to expect in what situations.
Tics will have a recognizable pattern of movement/manifestation.
Functional tic-like behaviors are frequently unpredictable.
They will not be likely to manifest the same way consistently in the same situation.
Tics may weaken or disappear when engaged in or focused on an activity.
Eg. a patient's tics might disappear when they are focused on playing the piano.
Functional tic-like behaviors do not show this distractibility.
Tics may be triggered or worsened by discussing or thinking about them.
New tics are not readily picked up from others.
As discussed above, tics develop and progress very slowly.
Functional tic-like behaviors may be triggered or worsened by discussing or thinking about them.
New tic-like behaviors are picked up from others extremely readily.
Patients often experience tic-like behaviors similar to tics they have seen others perform.
When new tic-like behaviors are picked up they can result in a positive feedback loop.
The patient thinks the movement is a tic or that they have TS.
The patient assumes that they will develop more tics.
The patient begins to develop more and more tics as a result.
Repeat.
Tics may feel like they have to be performed in a certain way or a certain number of times.
Sometimes referred to as "just right OCD" or "Tourettic OCD."
Functional tic-like behaviors are not associated with OCD or OCD traits.
Tic disorders affect the nervous system
They affect the sensory and motor (movement) signals between the brain and body.
MRIs show hyperactive amygdalae in FNSD patients.
The fear and anxiety centers get activated when they should not be.
MRIs show underactive right temporal parietal junctions.
Patients cannot tell when a movement is voluntary or not.
Functional tics are triggered by the mind needing to release building stress or anxiety.
They are "functional" because they serve the function of releasing this stress.
The brain takes a stimulus and converts it into a physical symptom.
Functional tic-like behaviors are the result of the mind unconsciously mimicking TS.
Often based on observations of others who claim to have TS.
Because these behaviors mimic TS based on the patient's perception, they often present differently than would be expected from TS.
If a patient has both TS and FND their tic-like behaviors may appear more alike to tics.
They will feel different, however.
Tics naturally wax and wane in intensity and frequency over time.
Tics are generally at their most severe between ages 9-15 (peak at 12.3 years old).
Functional tic-like behaviors affect patients more consistently.
Functional tic-like behaviors show up later in adolescence.
Tics are rarely disruptive or painful.
When they are, patients will report this and ask for help.
Patients will frequently experience tics for many years before deciding to get diagnosed.
Tics may disappear during sleep.
Functional tic-like behaviors are more dramatically disruptive or painful.
'Tic attacks' are common (discussed below).
Functional tic-like behaviors may disrupt sleep or keep patients awake.
'Tic attacks' may occur, but they are not characteristic of tic disorders.
'Tic attacks' are specifically characteristic of functional tic-like behaviors (Quezada et al., 2021).
They are sudden explosions of combinations of tic-like behaviors.
'Tic attacks' can go on for hours.
'Tic attacks' may be described as "seizure-like."
Tic disorders are not entirely curable, only treatable.
Comprehensive Behavioral Intervention for Tics (CBIT) is a common strategy.
Treatment of FNSD focuses on resolving the root of the stress/anxiety and on emotional control.
Make empathetic diagnosis (patients are resilient and tend to rely on avoidance and denial related to the stress and anxiety behind the disorder).
Treat coöccurring conditions or stressors (tic-like behaviors will not improve until anxiety/depression/stressors/etc. improves first).
Cognitive behavioral therapy (CBT) - learn to recognize what thoughts lead to symptoms and how you can break the pattern (ie. learning to deactivate the hyperactive amygdala).
Tic patients are generally very embarrassed by their tics and will try to hide them.
Patients will rarely want to share or show off their tics.
Functional tic-like behavior patients tend to be more comfortable displaying or sharing their tics.
This means that patients with tic-like behaviors who pick up their behaviors from internet personalities are often developing them from other people with tic-like behaviors and not people with tics like TS.
Tourette Canada. (n.d.). Tic Disorders. Tourette Canada. https://tourette.ca/wp-content/uploads/2016/10/DSM-5_Tic_Disorders.pdf
International Classification of Diseases, Eleventh Revision (ICD-11), World Health Organization (WHO) 2019/2021 https://icd.who.int/browse11. Licensed under Creative Commons Attribution-NoDerivatives 3.0 IGO licence (CC BY-ND 3.0 IGO).
American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
Center for Disease Control and Prevention. (2022, May 17). Diagnosing tic disorders. https://www.cdc.gov/ncbddd/tourette/diagnosis.html
Coffman, K., & Quezada, J. (2021, December 15). TikTok tics - Tourette syndrome and FND. [Webinar]. Tourette Association of America. https://tourette.org/tiktok-tics/
Quezada, j., Anderson, S., Bennett, S., Black, K. J., Coffman, K. A., Greenberg, E., Malaty, I. A. C., Müller-Vahl, K. R., Okun, M. S., & Robichaux-Viehoever, A. (2021, November 22). Rising incidence of functional tic-like behaviors. https://tourette.org/rising-incidence-of-functional-tic-like-behaviors/
Jankovic J. (2015). Therapeutic Developments for Tics and Myoclonus. Movement disorders : official journal of the Movement Disorder Society, 30(11), 1566–1573. https://doi.org/10.1002/mds.26414
National Institute of Neurological Disorders and Stroke. (2021, August 2). Functional Neurologic Disorder. https://www.ninds.nih.gov/health-information/patient-caregiver-education/fact-sheets/functional-neurologic-disorder
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Robakis D. (2017). How Much Do We Know about Adult-onset Primary Tics? Prevalence, Epidemiology, and Clinical Features. Tremor and other hyperkinetic movements (New York, N.Y.), 7, 441. https://doi.org/10.7916/D8SQ95ND
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