Clinical pharmacology of nondopaminergic drugs in Tourette syndrome

European clinical guidelines for Tourette syndrome and other tic disorders-version 2.0. Part III: pharmacological treatment

In 2011, the European Society for the Study of Tourette Syndrome (ESSTS) published the first European guidelines for Tourette Syndrome (TS). We now present an update of the part on pharmacological treatment, based on a review of new literature with special attention to other evidence-based guidelines, meta-analyses, and randomized double-blinded studies. Moreover, our revision took into consideration results of a recent survey on treatment preferences conducted among ESSTS experts. The first preference should be given to psychoeducation and to behavioral approaches, as it strengthens the patients' self-regulatory control and thus his/her autonomy. Because behavioral approaches are not effective, available, or feasible in all patients, in a substantial number of patients pharmacological treatment is indicated, alone or in combination with behavioral therapy. The largest amount of evidence supports the use of dopamine blocking agents, preferably aripiprazole because of a more favorable profile of adverse events than first- and second-generation antipsychotics. Other agents that can be considered include tiapride, risperidone, and especially in case of co-existing attention deficit hyperactivity disorder (ADHD), clonidine and guanfacine. This view is supported by the results of our survey on medication preference among members of ESSTS, in which aripiprazole was indicated as the drug of first choice both in children and adults. In treatment resistant cases, treatment with agents with either a limited evidence base or risk of extrapyramidal adverse effects might be considered, including pimozide, haloperidol, topiramate, cannabis-based agents, and botulinum toxin injections. Overall, treatment of TS should be individualized, and decisions based on the patient's needs and preferences, presence of co-existing conditions, latest scientific findings as well as on the physician's preferences, experience, and local regulatory requirements.

Efficacy of nicotine administration on obsessions and compulsions in OCD: a systematic review

BACKGROUND

Preliminary studies have tested nicotine as a novel treatment for OCD patients who respond partially/incompletely or not at all to first and second-line treatment strategies, with the former represented by SSRIs or clomipramine, and the latter by switching to another SSRI, or augmentation with atypical antipsychotics, and/or combination with/switching to cognitive-behavioural therapy. Some studies found nicotine-induced reduction of obsessive thoughts and/or compulsive behaviour in OCD patients. We aimed to evaluate the efficacy of nicotine administration in OCD patients.

METHODS

We searched the PubMed, ScienceDirect Scopus, CINHAL, Cochrane, PsycINFO/PsycARTICLES, and EMBASE databases from inception to the present for relevant papers. The 'Preferred Reporting Items for Systematic Review and Meta-Analyses' (PRISMA) standards were used. We included all studies focusing on the effects of nicotine administration on OCD patients' obsessions or compulsions. Studies could be open-label, cross-sectional, randomized controlled trials, case series or case reports.

RESULTS

A total of five studies could be included. Nicotine administration may ameliorate behavioural features and recurrent thoughts of severe, treatment-resistant OCD patients; however, in one study it was not associated with OC symptom improvement or cognitive enhancement across various executive function subdomains.

CONCLUSIONS

Although encouraging, the initial positive response from the use of nicotine in OCD needs testing in large controlled studies. This, however, raises ethical issues related to nicotine administration, due to its addiction potential, which were not addressed in the limited literature we examined. As an alternative, novel treatments with drugs able to mimic only the positive effects of nicotine could be implemented.

Efficacy and safety of traditional Chinese medicine for Tourette's syndrome: A meta-analysis of randomized controlled trials

BACKGROUND

Traditional Chinese medicine (TCM) has been widely used in the treatment of Tourette's Syndrome (TS). However, the efficacy and safety of TCM in treating TS are mixed across studies. This is a meta-analysis of studies on the efficacy and safety of TCM compared to placebo and Western medicine (WM).

METHODS

PubMed, Cochrane Library, PsycINFO, Chinese National Knowledge Infrastructure, SinoMed, and WanFang databases were systematically searched from inception date to October 16, 2018. Randomized Controlled Trials (RCTs) on the efficacy and safety of TCM alone or TCM + WM combination for TS were included.

RESULTS

A total of 15 studies comprising 21 treatment trials (n = 2824) were included. TCM alone was more efficacious than placebo in terms of response rate (Relative Risk, RR: 1.96, 95% CI: 1.55-2.47, P < 0.01, I² = 45 %) and the change in the Yale Global Tic Severity Scale total score (Standard mean difference, SMDs: -0.67, 95% CI: -0.81, -0.53, P < 0.01, I² = 0 %). The results remained positive when TCM alone was compared with WM alone (RR: 1.06, 95% CI: 1.00-1.12, P = 0.03, I² = 29 %), and when TCM + WM were compared with WM alone (RR: 1.24, 95% CI: 1.08-1.43, P < 0.01, I² = 0 %). Adverse drug reactions were more frequent in WM than in TCM groups (P < 0.05). WM type (P = 0.02), proportion of males (P = 0.03) and trial duration (P = 0.03) were significantly associated with response rate in TS patients when comparing TCM alone with WM alone.

CONCLUSION

The results of this meta-analysis support the efficacy and safety of TCM alone and TCM + WM in TS patients.

A Bayesian Account of the Sensory-Motor Interactions Underlying Symptoms of Tourette Syndrome

Tourette syndrome is a hyperkinetic movement disorder. Characteristic features include tics, recurrent movements that are experienced as compulsive and "unwilled"; uncomfortable premonitory sensations that resolve through tic release; and often, the ability to suppress tics temporarily. We demonstrate how these symptoms and features can be understood in terms of aberrant predictive (Bayesian) processing in hierarchical neural systems, explaining specifically: why tics arise, their "unvoluntary" nature, how premonitory sensations emerge, and why tic suppression works-sometimes. In our model, premonitory sensations and tics are generated through over-precise priors for sensation and action within somatomotor regions of the striatum. Abnormally high precision of priors arises through the dysfunctional synaptic integration of cortical inputs. These priors for sensation and action are projected into primary sensory and motor areas, triggering premonitory sensations and tics, which in turn elicit prediction errors for unexpected feelings and movements. We propose experimental paradigms to validate this Bayesian account of tics. Our model integrates behavioural, neuroimaging, and computational approaches to provide mechanistic insight into the pathophysiological basis of Tourette syndrome.

A Single Case of Tourette's Syndrome Treated with Traditional Chinese Medicine

The objective of this case study was to investigate the effectiveness of Chinese medicine in treating Tourette's syndrome. Tourette's syndrome is a childhood- onset disorder that is characterized by sudden, involuntary movements or tics. The participant in this study was a 33-year-old male who had been diagnosed with Tourette's syndrome at the age of 9 years. His major complaints included facial tics, shoulder shrugging, and clearing the throat. Using a combination of acupuncture, herbs, Gua-Sha, and lifestyle changes once a week for 35 treatments, all the symptoms were reduced by 70%, as reported by the patient. In this case, the results indicated that Chinese medicine was able to minimize the symptoms of Tourette's syndrome. Further investigation is needed to support this argument. Tourette's syndrome, which was first described in 1885 by a French physician named Gilles de la Tourette, is characterized by facial tics, involuntary body movements from the head to the extremities, or vocal tics, and it usually has its onset in childhood. It is a neuropsychiatric disorder. The treatment for Tourette's syndrome is based on pharmacological treatment, behavior treatment, and deep brain stimulation. Unfortunately, none of these could completely control the symptoms; furthermore, antipsychiatric drugs might cause additional side effects, such as Parkinson symptoms, tardive dyskinesia, and metabolic disturbances. Finding acupuncture and oriental medicine literature on treatment of Tourette's syndrome was difficult, especially that written in English. Some research papers that have been translated into English indicated that Chinese herbs and acupuncture could reduce the tics significantly. For example, a study by Dr Pao-Hua Lin reported the significant effects of using acupuncture and oriental medicine in treating 1000 Tourette's syndrome cases. This case was treated to further investigate the principles of Dr Lin's study.

Tetrabenazine: Spotlight on Drug Review

BACKGROUND

Tetrabenazine (TBZ) is the only US Food and Drug Administration-approved drug for the treatment of chorea related to Huntington's disease and other hyperkinetic disorders. TBZ was first synthesized in 1950, and was then used for the treatment of psychosis. But later its potential in treating hyperkinetic disorders was proved by its ability to block vesicular monoamine transporters 2 and deplete monoamine stores. There is still lack of awareness about the therapeutic potential of this drug.

SUMMARY

TBZ had been approved only for the treatment of chorea, but several clinical studies have been conducted by different research groups and it was concluded that TBZ is effective in various other conditions such as tardive dyskinesia, dystonia, tics, and Tourette's syndrome, thus, highlighting the need for further clinical trials in these conditions.

KEY MESSAGE

The intention of this review is to sum up the information regarding chemistry, mechanism of action, pharmacokinetics, interactions, contraindications, adverse effects, and clinical efficacy of TBZ in diseases other than Huntington's chorea.

Targeted ablation of cholinergic interneurons in the dorsolateral striatum produces behavioral manifestations of Tourette syndrome

Gilles de la Tourette syndrome (TS) is characterized by tics, which are transiently worsened by stress, acute administration of dopaminergic drugs, and by subtle deficits in motor coordination and sensorimotor gating. It represents the most severe end of a spectrum of tic disorders that, in aggregate, affect ∼ 5% of the population. Available treatments are frequently inadequate, and the pathophysiology is poorly understood. Postmortem studies have revealed a reduction in specific striatal interneurons, including the large cholinergic interneurons, in severe disease. We tested the hypothesis that this deficit is sufficient to produce aspects of the phenomenology of TS, using a strategy for targeted, specific cell ablation in mice. We achieved ∼ 50% ablation of the cholinergic interneurons of the striatum, recapitulating the deficit observed in patients postmortem, without any effect on GABAergic markers or on parvalbumin-expressing fast-spiking interneurons. Interneuron ablation in the dorsolateral striatum (DLS), corresponding roughly to the human putamen, led to tic-like stereotypies after either acute stress or d-amphetamine challenge; ablation in the dorsomedial striatum, in contrast, did not. DLS interneuron ablation also led to a deficit in coordination on the rotorod, but not to any abnormalities in prepulse inhibition, a measure of sensorimotor gating. These results support the causal sufficiency of cholinergic interneuron deficits in the DLS to produce some, but not all, of the characteristic symptoms of TS.