Tic Disorders

Tic disorders are neurodevelopmental conditions characterised by sudden, rapid, recurrent, non-rhythmic motor movements or vocalisations (tics). Tics affect a substantial proportion of children transiently at some point during development.

The disorders are classified by duration, complexity, and the presence of motor and vocal components:

• Provisional tic disorder: motor and/or vocal tics present for less than twelve months.
• Persistent (chronic) motor or vocal tic disorder: either motor or vocal tics, though not both, present for twelve months or longer.
• Tourette syndrome: both multiple motor tics and one or more vocal tics present, though not necessarily concurrently, for twelve months or longer.

Clinical priorities are accurate classification, assessment for coexisting neurodevelopmental and psychiatric conditions, and proportionate, generally conservative management. Attention deficit hyperactivity disorder and obsessive compulsive disorder both occur with increased frequency in this population. The natural history characteristically fluctuates and often improves spontaneously.

Pathophysiology and classification

• Simple tics involve a single, isolated muscle group or sound, such as eye blinking, shoulder shrugging, or sniffing.
• Complex tics involve a coordinated sequence of movements or a more complex, recognisable vocalisation, such as touching or jumping.
• Coprolalia is the involuntary utterance of obscene or inappropriate words or phrases. It occurs in only a small minority of affected individuals, despite its disproportionate public recognition. It is a common but inaccurate perception that it defines Tourette syndrome.
• The underlying pathophysiology is dysfunction within cortico-striato-thalamo-cortical neural circuitry, broadly similar to that implicated in obsessive compulsive disorder. This reflects the close relationship and frequent coexistence of the two conditions.
• Genetic predisposition is strong. In some individuals, environmental and streptococcal infection-related triggers have been proposed within the controversial PANDAS (paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) hypothesis. This remains an area of ongoing scientific debate and research, not an established, universally accepted mechanism.
• A premonitory sensation is reported by the majority of affected individuals, particularly older children and adults with sufficient insight and verbal capacity to describe it. It is an uncomfortable, building physical urge or sensation preceding the tic, generally relieved, at least temporarily, by performing the tic. It is a target for certain behavioural treatment approaches.

• Tics characteristically wax and wane in frequency, severity, and character over time. They tend to worsen during periods of stress, excitement, fatigue, or illness, and improve during periods of calm, focused concentration on an absorbing task.
• This pattern aids diagnostic recognition and counselling of patients and families about the variable natural course.
• Tics are characteristically suppressible, at least temporarily and with conscious effort. Suppression frequently comes at the cost of increasing internal discomfort or a sense of building tension.
• It is often followed by a sometimes more pronounced "rebound" increase in tic frequency once the suppression effort is relaxed. This is relevant when educating patients and families about expectations of tic suppression, particularly in structured settings such as school.
• Motor tics typically begin in early to middle childhood, commonly around the face and head initially. Eye blinking is a frequently reported early, first presenting tic.
• Tics tend to evolve in character and migrate to different body regions over time. Vocal tics, when present, typically emerge somewhat later than the initial motor tics.
• Coexisting conditions occur with increased frequency, most notably attention deficit hyperactivity disorder and obsessive compulsive disorder. Both occur in a substantial proportion of children with Tourette syndrome. Anxiety is also more common.
• In many cases the functional impact and distress from these coexisting conditions exceeds that attributable to the tics themselves. Assessing and treating them is an integral, sometimes primary, component of management.
• Severity and functional impact vary enormously. Tics range from mild and barely noticeable, with minimal distress, to severe, frequent and complex. Severe tics cause social embarrassment, physical discomfort or, rarely, injury, and significant functional impairment.
• Management and its intensity are individualised to this variation in severity and impact.

• Diagnosis is clinical. It rests on the pattern and duration of motor and/or vocal tics meeting the diagnostic criteria for the relevant tic disorder subtype. No laboratory or neuroimaging investigation is routinely needed in a typical, straightforward presentation.
• Assess for coexisting attention deficit hyperactivity disorder, obsessive compulsive disorder, and anxiety using structured assessment approaches. This is an essential part of evaluation, given their frequent coexistence and relevance to functional impact and management planning.
• Distinguish tics from other movement phenomena: stereotypies, myoclonus, and where relevant chorea or other movement disorders.
• Stereotypies are repetitive, patterned movements more typically associated with autism spectrum disorder or intellectual disability. They generally lack the premonitory urge and suppressibility of true tics.
• The characteristic features of tics generally support confident clinical distinction in the great majority of presentations. These are a waxing and waning course, suppressibility, and the premonitory sensation where the individual has sufficient insight to report it.
• Further investigation to exclude an alternative cause may be warranted where the presentation is atypical, of unusually acute or explosive onset, or accompanied by other concerning neurological or systemic features. This is uncommon.

• Psychoeducation for the child, family, and where relevant school is the essential, foundational component of management for the great majority of presentations. Cover the waxing and waning course, and the generally involuntary, though partially and temporarily suppressible, nature of tics. Accurate understanding and appropriate expectations reduce distress and unhelpful reactions from the individual and those around them.
• Watchful waiting, without active treatment, is appropriate for mild tics causing minimal distress or functional impact. The natural history fluctuates, and a substantial proportion of children, particularly those with provisional tic disorder, experience spontaneous resolution or substantial improvement over time.
• Full behavioural intervention for tics is an effective, evidence-based, first line active treatment where tics cause significant distress or functional impact. It is a structured therapy incorporating habit reversal training, in which the individual learns to recognise the premonitory urge and substitute a competing, incompatible response for the tic. It avoids medication and its adverse effects.
• Consider pharmacological treatment for tics causing significant distress, social impairment, physical discomfort or injury risk that psychoeducation and behavioural intervention alone have not adequately addressed.
• Alpha-2 adrenergic agonists (guanfacine or clonidine) are a commonly used first line option. They are particularly useful where coexisting attention deficit hyperactivity disorder is present, given some overlapping benefit for both conditions.
• Antipsychotic medication is a more potent but generally reserved second line option, given the more substantial adverse effect profile of this class. Options include aripiprazole and risperidone. For more severe, refractory tics, the more traditional agents including haloperidol are used.
• Manage coexisting attention deficit hyperactivity disorder and obsessive compulsive disorder by the principles for those conditions. Consider carefully the interaction between treatment of a coexisting condition and tic severity.
• Stimulant medication was historically believed to exacerbate tics. More contemporary evidence indicates it is generally safe and appropriate for the great majority of children with coexisting attention deficit hyperactivity disorder and tics.
• Offer ongoing psychosocial support for any associated social difficulty, bullying, or self-esteem impact, with educational support and accommodation where relevant.
• Arrange ongoing longitudinal follow up, because the natural history fluctuates and both tic severity and any coexisting condition may evolve over time. Management should remain individualised and proportionate for this common, generally benign, though occasionally significantly impairing, spectrum of childhood neurodevelopmental conditions.