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PAGE 42 then , in real time , practice-detecting occurrences of the tics and the aversive ‘ premonitory urge ’ sensations that often precede them . They are then taught to engage in a ‘ competing response ’ every time the urge or tic occurs . This is an inconspicuous action that is physically incompatible with the tic . The social support component involves teaching the patient ’ s parent ( or another person ) to praise the patient for using the competing response correctly and to remind them to use the competing response when the patient is seen doing a tic without using the competing response . Habit reversal training is believed to work by facilitating habituation to the premonitory urge one tic at a time , while exposure and response prevention ( ERP ) helps to target many different tics at once . 23
More recently , as evidence has accrued that other contextual factors can also maintain and worsen tics , additional treatment components have been added to HRT . The result is CBIT , which integrates psychoeducation about tics , HRT , relaxation training and function-based treatments . CBIT identifies and helps the patient to modify the contextual factors that worsen tics to bring about tic reduction and decreased impairment .
A four-year multisite randomised controlled study of CBIT in 9-17-yearold children compared the efficacy of an eight-session ( over 10 weeks ) CBIT protocol with a psychoeducation and supportive therapy control condition . 25 Results of this study demonstrated that 52.5 % of the participants in the CBIT group were acute-phase treatment responders , compared with 18 % of the psychoeducation and supportive therapy group . Tic medication status did not moderate treatment outcome , suggesting that CBIT provided benefits above and beyond psychoeducation and supportive therapy regardless of whether or not they were already on a tic-reducing medication . In addition , gains from CBIT persisted for up to six months and resulted in decreased psychosocial impairment . GPs can refer to clinical psychologists under a mental health care plan for evidence-based behavioural treatments — such as ERP , HRT and CBIT — although access to therapists with expertise in the behavioural treatments for tics is limited in Australia .
PROGNOSIS
THE lifetime course of GTS disorder is characterised by waxing and waning of symptoms . Symptoms may worsen in early- to mid-adolescence , but after that , tics typically improve with age . In 10-20 % of patients , the tic symptoms will remit completely by late adolescence . While most patients with GTS will show significant improvement by early adulthood , in a minority , the tics will persist in a severe form into adult life . 26
It is , however , critical to consider that comorbid conditions — OCD in particular — and mood- and learning-related difficulties more commonly persist into adulthood and therefore can become the focus of clinical attention . 27
There is little evidence that dietary modification , allergy testing or environmental allergen control can minimise tics , although some patients may notice seasonal changes or environmental triggers linked to the waxing and waning course .
Obsessional impacts
Physical impacts
Figure 6 . Stylised depiction of quality-of-life domains affected in GTS . The quality of life ( QOL ) of patients with GTS is affected in several domains , which are influenced by tics and other conditions associated with GTS .
GTS significantly impacts the quality of life throughout the lifespan of the individual and covers several domains ( see figure 6 ). 2
THE FUTURE
FOR medically refractory tics , deep brain stimulation ( see figure 7 ) has been tried with varying success . Deep brain stimulation involves the implantation of electrodes deep in the brain for chronic stimulation and is aimed at disrupting neural activity in the target regions . This therapy is a well-established treatment for severe and intractable Parkinson ’ s disease , dystonia and essential tremor . There have been a few reports of deep brain stimulation in severe tic disorders , including Australian cases . 28 Since this is an invasive procedure with potential risks , it should be considered only in adult patients with chronic and severe tic disorders who have medically intractable disease and severe functional impairment . Patients require evaluation by a team with expertise in the management of tic disorders , and while considering surgery for patients below the age of 18 , it is recommended that a local ethics committee is consulted .
Figure 7 . Deep brain stimulation .
Psychological impacts
Tics
Associated clinical features
Comorbidities ( for example , OCD and ADHD )
Coexisting psychopathologies
School and / or work impacts
Cognitive impacts
Social impacts
QOL domains Factors associated with GTS
Nature Reviews / Disease Primers
Deep Brain Stimulation ( DBS )
Image reproduced with permission Nature Reviews Disease Primer .