Recent advances in Tourette syndrome
Open accessAbstract
PURPOSE OF REVIEW: This review considers the recent literature pertaining to the neurobiology, genetics and treatment of Tourette syndrome. RECENT FINDINGS: Over the last several years, both neuropathological and genetic findings have further focused attention on long-standing hypotheses regarding the role of the basal ganglia in causing tics and Tourette syndrome. Moreover, although the field awaits the results the first large-scale genetic studies, recent findings have already mirrored developments in the neuropsychiatric genetics literature more broadly, highlighting the value of the study of rare variation and the overlap of risks among seemingly disparate diagnostic categories. Finally, treatment studies have underscored the importance of cognitive-behavioral as well as pharmacological interventions for the treatment of tic disorders. SUMMARY: Recent findings have led to novel, testable hypotheses regarding the molecular and cellular mechanisms underlying Tourette syndrome. These, in turn, have begun to provide new avenues to conceptualizing treatment strategies. Although the development of additional medication options is a pressing need, recent data has demonstrated both the safety and efficacy of nonpharmacological approaches.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Administration of dopamine antagonists such as risperidone and haloperidol is effective in suppressing tics in most TS patients.
“Several clinical trials have shown that administration of dopamine antagonists, such as risperidone and haloperidol, are effective in suppressing tics in most patients (Bloch et al., 2011; Roessner et al., 2011).”
From Response Inhibition and Interference Control in Obsessive–Compulsive Spectrum Disorders (2014) · cites this paper as Bloch et al., 2011
The Recent Advances in Treatment section (page unavailable) reports that antipsychotics reduce tics, citing medium-to-large effects in several randomized, placebo-controlled trials. The Recent Advances in Neurobiology section identifies D2-blocking neuroleptics as effective TS medication. Our copy does not establish that risperidone and haloperidol specifically suppress tics in most patients. (LLM, conf=0.86)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
Cites
Strong association of de novo copy number mutations with autism
Sebat, J., Lakshmi, B., Malhotra, D., Troge, J., Lese-Martin, C., Walsh, T., Yamrom, B., Yoon, S., Krasnitz, A., Kendall, J., et al. (2007) · Science · doi:10.1126/science.1138659 · Cited by 2,795 · see citing works
Mutations of the X-linked genes encoding neuroligins NLGN3 and NLGN4 are associated with autism
Study, P. A. R. I. S., Jamain, S., Quach, H., Betancur, C., Råstam, M., Colineaux, C., Gillberg, I. C., Soderstrom, H., Giros, B., Leboyer, M., et al. (2003) · Nature Genetics · doi:10.1038/ng1136 · Cited by 1,851 · see citing works
Association between Microdeletion and Microduplication at 16p11.2 and Autism
Weiss, L. A., Shen, Y., Korn, J. M., Arking, D. E., Miller, D. T., Fossdal, R., Saemundsen, E., Stefansson, H., Ferreira, M. A. R., Green, T., et al. (2008) · New England Journal of Medicine · doi:10.1056/nejmoa075974 · Cited by 1,666 · see citing works
Histamine in the Nervous System
Haas, H. L., Sergeeva, O. A., & Selbach, O. (2008) · Physiological Reviews · doi:10.1152/physrev.00043.2007 · Cited by 1,227 · see citing works
Linkage, association, and gene-expression analyses identify CNTNAP2 as an autism-susceptibility gene
Alarcón, M., Abrahams, B. S., Stone, J. L., Duvall, J. A., Perederiy, J. V., Bomar, J. M., Sebat, J., Wigler, M., Martin, C. L., Ledbetter, D. H., et al. (2008) · The American Journal of Human Genetics · doi:10.1016/j.ajhg.2007.09.005 · Cited by 818 · see citing works
Recurrent rearrangements of chromosome 1q21.1 and variable pediatric phenotypes
Mefford, H. C., Sharp, A. J., Baker, C., Itsara, A., Jiang, Z., Buysse, K., Huang, S., Maloney, V. K., Crolla, J. A., Baralle, D., et al. (2008) · New England Journal of Medicine · doi:10.1056/nejmoa0805384 · Cited by 804 · see citing works
Laumonnier, F., Bonnet-Brilhault, F., Gomot, M., Blanc, R., David, A., Moizard, M.-P., Raynaud, M., Ronce, N., Lemonnier, E., Calvas, P., et al. (2004) · The American Journal of Human Genetics · doi:10.1086/382137 · Cited by 768 · see citing works
Behavior Therapy for Children With Tourette Disorder
Piacentini, J. C., Woods, D. W., Scahill, L. D., Wilhelm, S., Peterson, A. L., Chang, S. W., Ginsburg, G. S., Deckersbach, T., Dziura, J., Levi-Pearl, S., et al. (2010) · JAMA · doi:10.1001/jama.2010.607 · Cited by 722 · see citing works
Microduplications of 16p11.2 are associated with schizophrenia
Wellcome Trust Case Control Consortium, McCarthy, S. E., Makarov, V., Kirov, G., Addington, A. M., McClellan, J., Yoon, S., Perkins, D. O., Dickel, D. E., Kusenda, M., et al. (2009) · Nature Genetics · doi:10.1038/ng.474 · Cited by 711 · see citing works
Leckman, J. F. (2002) · The Lancet · doi:10.1016/s0140-6736(02)11526-1 · Cited by 683 · see citing works
A functional genetic link between distinct developmental language disorders
Vernes, S. C., Newbury, D. F., Abrahams, B. S., Winchester, L., Nicod, J., Groszer, M., Alarcón, M., Oliver, P. L., Davies, K. E., Geschwind, D. H., et al. (2008) · New England Journal of Medicine · doi:10.1056/nejmoa0802828 · Cited by 676 · see citing works
Recessive symptomatic focal epilepsy and mutant contactin-associated protein-like 2
Strauss, K. A., Puffenberger, E. G., Huentelman, M. J., Gottlieb, S., Dobrin, S. E., Parod, J. M., Stephan, D. A., & Morton, D. H. (2006) · New England Journal of Medicine · doi:10.1056/nejmoa052773 · Cited by 630 · see citing works
Antipsychotic-induced weight gain: a review of the literature.
Allison, D. B., & Casey, D. E. (2001) · PubMed · Cited by 596 · see citing works
Arking, D. E., Cutler, D. J., Brune, C. W., Teslovich, T. M., West, K., Ikeda, M., Rea, A., Guy, M., Lin, S., Cook, E. H., et al. (2008) · The American Journal of Human Genetics · doi:10.1016/j.ajhg.2007.09.015 · Cited by 590 · see citing works
Coincident but Distinct Messages of Midbrain Dopamine and Striatal Tonically Active Neurons
Morris, G., Arkadir, D., Nevet, A., Vaadia, E., & Bergman, H. (2004) · Neuron · doi:10.1016/j.neuron.2004.06.012 · Cited by 574 · see citing works
Kalanithi, P. S. A., Zheng, W., Kataoka, Y., DiFiglia, M., Grantz, H., Saper, C. B., Schwartz, M. L., Leckman, J. F., & Vaccarino, F. M. (2005) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0502624102 · Cited by 543 · see citing works
Bakkaloglu, B., O'Roak, B. J., Louvi, A., Gupta, A. R., Abelson, J. F., Morgan, T. M., Chawarska, K., Klin, A., Ercan-Sencicek, A. G., Stillman, A. A., et al. (2008) · The American Journal of Human Genetics · doi:10.1016/j.ajhg.2007.09.017 · Cited by 537 · see citing works
Self-citationBasal Ganglia Volumes in Patients With Gilles de la Tourette Syndrome
Peterson, B. S., Thomas, P., Kane, M. J., Scahill, L., Zhang, H., Bronen, R., King, R. A., Leckman, J. F., & Staib, L. (2003) · Archives of General Psychiatry · doi:10.1001/archpsyc.60.4.415 · Cited by 527 · see citing works
Treatment of ADHD in children with tics: A randomized controlled trial
The Tourette’s Syndrome Study Group (2002) · Neurology · doi:10.1212/wnl.58.4.527 · Cited by 504 · see citing works
The Inheritance of Gilles de la Tourette's Syndrome and Associated Behaviors
Pauls, D. L., & Leckman, J. F. (1986) · New England Journal of Medicine · doi:10.1056/nejm198610163151604 · Cited by 494 · see citing works
A Functional Magnetic Resonance Imaging Study of Tic Suppression in Tourette Syndrome
Peterson, B. S., Skudlarski, P., Anderson, A. W., Zhang, H., Gatenby, J. C., Lacadie, C. M., Leckman, J. F., & Gore, J. C. (1998) · Archives of General Psychiatry · doi:10.1001/archpsyc.55.4.326 · Cited by 483 · see citing works
Bloch, M. H., Peterson, B. S., Scahill, L. D., Otka, J., Katsovich, L., Heping Zhang, D., & Leckman, J. F. (2006) · Archives of Pediatrics and Adolescent Medicine · doi:10.1001/archpedi.160.1.65 · Cited by 457 · see citing works
Self-citationKataoka, Y., Kalanithi, P. S. A., Grantz, H., Schwartz, M. L., Saper, C. B., Leckman, J. F., & Vaccarino, F. M. (2009) · The Journal of Comparative Neurology · doi:10.1002/cne.22206 · Cited by 457 · see citing works
L-Histidine Decarboxylase and Tourette's Syndrome
Ercan‐Sencicek, A. G., Stillman, A. A., Ghosh, A. K., Bilgüvar, K., O’Roak, B. J., Mason, C. E., Abbott, T. B., Gupta, A. R., King, R. A., Pauls, D. L., et al. (2010) · New England Journal of Medicine · doi:10.1056/nejmoa0907006 · Cited by 358 · see citing works
Self-citationA Twin Study of Tourette Syndrome
Price, R. A. (1985) · Archives of General Psychiatry · doi:10.1001/archpsyc.1985.01790310077011 · Cited by 351 · see citing works
A Functional Neuroanatomy of Tics in Tourette Syndrome
Stern, E., Silbersweig, D., Chee, K.-Y., Holmes, A., Robertson, M. M., Trimble, M., Frith, C., Frackowiak, R. S. J., & Dolan, R. J. (2000) · Archives of General Psychiatry · doi:10.1001/archpsyc.57.8.741 · Cited by 338 · see citing works
Caudate volumes in childhood predict symptom severity in adults with Tourette syndrome
Bloch, M. H., Leckman, J. F., Zhu, H., & Peterson, B. S. (2005) · Neurology · doi:10.1212/01.wnl.0000180957.98702.69 · Cited by 326 · see citing works
Self-citationTic disorders and ADHD: answers from a world-wide clinical dataset on Tourette syndrome
Freeman, R. D., & Tourette Syndrome International Database Consortium (2007) · European Child & Adolescent Psychiatry · doi:10.1007/s00787-007-1003-7 · Cited by 318 · see citing works
Tourette's syndrome: from behaviour to biology
Singer, H. S. (2005) · The Lancet Neurology · doi:10.1016/s1474-4422(05)01012-4 · Cited by 309 · see citing works
Contemporary assessment and pharmacotherapy of Tourette syndrome
Scahill, L., Erenberg, G., Berlin, C. M., Budman, C., Coffey, B. J., Jankovic, J., Kiessling, L., King, R. A., Kurlan, R., Lang, A., et al. (2006) · NeuroRX · doi:10.1016/j.nurx.2006.01.009 · Cited by 300 · see citing works
Robertson, M., Eapen, V., & Cavanna, A. (2009) · Journal of Psychosomatic Research · doi:10.1016/j.jpsychores.2009.07.010 · Cited by 288 · see citing works
Whitaker, A. H. (1997) · Archives of General Psychiatry · doi:10.1001/archpsyc.1997.01830210091012 · Cited by 272 · see citing works
Bloch, M. H., Panza, K. E., Landeros-Weisenberger, A., & Leckman, J. F. (2009) · Journal of the American Academy of Child & Adolescent Psychiatry · doi:10.1097/chi.0b013e3181b26e9f · Cited by 270 · see citing works
Self-citationFamilial deletion within NLGN4 associated with autism and Tourette syndrome
Lawson‐Yuen, A., Saldivar, J., Sommer, S. S., & Picker, J. D. (2008) · European Journal of Human Genetics · doi:10.1038/sj.ejhg.5202006 · Cited by 269 · see citing works
Verkerk, A., Mathews, C., Joosse, M., Eussen, B., Heutink, P., & Oostra, B. (2003) · Genomics · doi:10.1016/s0888-7543(03)00097-1 · Cited by 237 · see citing works
Prevalence of Diagnosed Tourette Syndrome in Persons Aged 6-17 Years - United States, 2007
(2009) · PsycEXTRA Dataset · doi:10.1037/e551952010-002 · Cited by 225 · see citing works
Threlfell, S., Clements, M. A., Khodai, T., Pienaar, I. S., Exley, R. A., Wess, J., & Cragg, S. J. (2010) · Journal of Neuroscience · doi:10.1523/jneurosci.5620-09.2010 · Cited by 224 · see citing works
Walkup, J. T., Labuda, M. C., Singer, H. S., Brown, J. E., Riddle, M. A., & Hurko, O. (1996) · PubMed Central · Cited by 203 · see citing works
Neurobiological Substrates of Tourette's Disorder
Leckman, J. F., Bloch, M. H., Smith, M. E., Larabi, D. I., & Hampson, M. (2010) · Journal of Child and Adolescent Psychopharmacology · doi:10.1089/cap.2009.0118 · Cited by 198 · see citing works
Self-citationTourette's syndrome: from behaviour to biology
Singer, H. S. (2005) · The Lancet Neurology · doi:10.1016/s1474-4422(05)70018-1 · Cited by 198 · see citing works
Histamine H3 Receptor Antagonists: Preclinical Promise for Treating Obesity and Cognitive Disorders
Esbenshade, T. A. (2006) · Molecular Interventions · doi:10.1124/mi.6.2.5 · Cited by 194 · see citing works
Jankovic, J. J., Shahed, J. J., & Brown, L. W. (2009) · Journal of Neurology Neurosurgery & Psychiatry · doi:10.1136/jnnp.2009.185348 · Cited by 193 · see citing works
The genetics of child psychiatric disorders: focus on autism and Tourette syndrome
State, M. W. (2010) · Neuron · doi:10.1016/j.neuron.2010.10.004 · Cited by 162 · see citing works
Self-citationAnxiety Disorders and Tic Severity in Juveniles With Tourette's Disorder
Coffey, B. J., Biederman, J., Smoller, J. W., GELLER, D. A., SARIN, P., SCHWARTZ, S., & KIM, G. S. (2000) · Journal of the American Academy of Child & Adolescent Psychiatry · doi:10.1097/00004583-200005000-00009 · Cited by 155 · see citing works
Leckman, J. F., Pauls, D. L., Heping Zhang, D., do Rosário, M. C., Katsovich, L., Kídd, K. K., PAKSTIS, A. J., Alsobrook, J. P., Robertson, M. M., McMahon, W. M., et al. (2002) · American Journal of Medical Genetics Part B Neuropsychiatric Genetics · doi:10.1002/ajmg.b.10001 · Cited by 154 · see citing works
Developmental psychopathology of children and adolescents with Tourette syndrome – impact of ADHD
Roessner, V., Becker, A., Banaschewski, T., Freeman, R. D., Rothenberger, A., & Tourette Syndrome International Database Consortium (2007) · European Child & Adolescent Psychiatry · doi:10.1007/s00787-007-1004-6 · Cited by 138 · see citing works
Weight and Leptin Changes Among Risperidone-Treated Youths With Autism: 6-Month Prospective Data
Martin, A., Scahill, L. D., Anderson, G. M., Aman, M. G., Arnold, L. E., McCracken, J. T., McDougle, C. J., Tierney, E., Chuang, S. Z., & Vitiello, B. (2004) · American Journal of Psychiatry · doi:10.1176/appi.ajp.161.6.1125 · Cited by 134 · see citing works
Tourette syndrome is associated with recurrent exonic copy number variants
Sundaram, S. K., Huq, A. M., Wilson, B. J., & Chugani, H. T. (2010) · Neurology · doi:10.1212/wnl.0b013e3181e0f147 · Cited by 126 · see citing works
Tourette syndrome and learning disabilities
Burd, L., Fréeman, R. D., Klug, M. G., & Kerbeshian, J. (2005) · BMC Pediatrics · doi:10.1186/1471-2431-5-34 · Cited by 110 · see citing works
Tic reduction with pergolide in a randomized controlled trial in children
Gilbert, D. L., Dure, L. S., Sethuraman, G., Raab, D., Lane, J. B., & Sallee, F. R. (2003) · Neurology · doi:10.1212/01.wnl.0000044058.64647.7e · Cited by 106 · see citing works
Association Between Maternal Smoking and Increased Symptom Severity in Tourette’s Syndrome
Mathews, C. A., Bimson, B. E., Lowe, T. L., Herrera, L. D., Budman, C. L., Erenberg, G., Naarden, A., BRUUN, R. D., Freimer, N. B., & Reus, V. I. (2006) · American Journal of Psychiatry · doi:10.1176/ajp.2006.163.6.1066 · Cited by 103 · see citing works
Tourette’s syndrome improvement with pergolide in a randomized, double-blind, crossover trial
Gilbert, D. L., Sethuraman, G., SINE, L. E., Peters, S., & Sallee, F. R. (2000) · Neurology · doi:10.1212/wnl.54.6.1310 · Cited by 102 · see citing works
Bilineal transmission in Tourette's syndrome families
Kurlan, R., Eapen, V., Stern, J. S., McDermott, M. P., & Robertson, M. M. (1994) · Neurology · doi:10.1212/wnl.44.12.2336 · Cited by 98 · see citing works
Braun, A. R. (1995) · Neuropsychopharmacology · doi:10.1016/0893-133x(95)00052-f · Cited by 97 · see citing works
A Controlled Family Study of Attention-Deficit/Hyperactivity Disorder and Tourette's Disorder
Stewart, S. E., Illmann, C., GELLER, D. A., Leckman, J. F., King, R. A., & Pauls, D. L. (2006) · Journal of the American Academy of Child & Adolescent Psychiatry · doi:10.1097/01.chi.0000251211.36868.fe · Cited by 90 · see citing works
Psychiatric disorders and behavioral problems in children and adolescents with Tourette syndrome
Ghanizadeh, A. J., & Mosallaei, S. (2008) · Brain and Development · doi:10.1016/j.braindev.2008.03.010 · Cited by 90 · see citing works
Kubota, Y., Ito, C., Sakurai, E., Sakurai, E., Watanabe, T., & Ohtsu, H. (2002) · Journal of Neurochemistry · doi:10.1046/j.1471-4159.2002.01189.x · Cited by 86 · see citing works
Genetic analysis of Tourette syndrome suggesting major gene effect.
Baron, M., Shapiro, E., Shapiro, A., & Rainer, J. D. (1981) · PubMed · Cited by 83 · see citing works
<i>Fgfr1</i>Is Required for Cortical Regeneration and Repair after Perinatal Hypoxia
Fagel, D. M., Ganat, Y., Cheng, E., Silbereis, J., Ohkubo, Y., Ment, L. R., & Vaccarino, F. M. (2009) · The Journal of Neuroscience · doi:10.1523/jneurosci.4516-08.2009 · Cited by 82 · see citing works
Intermediate inheritance of Tourette syndrome, assuming assortative mating.
Hasstedt, S. J., Leppert, M., Filloux, F. M., van de Wetering, B. J., & McMahon, W. M. (1995) · PubMed Central · Cited by 80 · see citing works
Autosomal Dominant Gene Transmission in a Large Kindred with Gilles de la Tourette Syndrome
Curtis, D., Robertson, M. M., & Gurling, H. (1992) · The British Journal of Psychiatry · doi:10.1192/bjp.160.6.845 · Cited by 79 · see citing works
Genetic hypotheses for Tourette syndrome.
Kk, K., & Dl, P. (1982) · PubMed · Cited by 68 · see citing works
Neuroimaging of Tourette Syndrome
Frey, K. A., & Albin, R. L. (2006) · Journal of Child Neurology · doi:10.1177/08830738060210080501 · Cited by 62 · see citing works
Behavioral and affective disorders in Tourette syndrome.
Robertson, M. M., & Orth, M. (2006) · PubMed · Cited by 29 · see citing works
Casey, M. B., Cohen, M., Schuerholz, L. J., Singer, H. S., & DENCKLA, M. B. (2000) · Developmental Neuropsychology · doi:10.1207/s15326942dn1701_06 · Cited by 19 · see citing works
Obsessive-compulsive disorder and Tourette Syndrome: is there a relationship?
do Rosário, M. C., & Miguel, E. C. (1997) · Sao Paulo Medical Journal · doi:10.1590/s1516-31801997000200008 · Cited by 3 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Dold, M., Aigner, M., Lanzenberger, R., & Kasper, S. (2013) · International Journal of Neuropsychopharmacology · doi:10.1017/s1461145712000740 · Cited by 211 · see citing works
Neuromodulation in Tourette syndrome: dopamine and beyond
Buse, J., Schoenefeld, K., Münchau, A., & Roessner, V. (2013) · Neuroscience & Biobehavioral Reviews · doi:10.1016/j.neubiorev.2012.10.004 · Cited by 185 · see citing works
Response Inhibition and Interference Control in Obsessive–Compulsive Spectrum Disorders
van Velzen, L. S., Vriend, C., de Wit, S. J., & van den Heuvel, O. A. (2014) · Frontiers in Human Neuroscience · doi:10.3389/fnhum.2014.00419 · Cited by 159 · see citing works
Predictors of the clinical course of Tourette syndrome: a longitudinal study.
Groth, C., Skov, L., Lange, T., & Debes, N. M. (2019) · Journal of Child Neurology · doi:10.1177/0883073819867245 · Cited by 58 · see citing works
- Authors
- Bloch, M., State, M., & Pittenger, C.
- Affiliations
- Yale University (US)
- Corresponding author
- Bloch, Michael
- State, Matthew
- Pittenger, Christopher
- Venue
- Current Opinion in Neurology
- Published
- 2011-04
- Volume
- 24
- Issue
- 2
- Pages
- 119-125
- ISSN
- 1350-7540 (ISSN-L)
- PMC
- PMC4065550
- OpenAlex
- W2153617058
- Cited by
- 91
- References
- 66
- Citations by year
- 2026: 1 · 2024: 1 · 2022: 2 · 2021: 2 · 2020: 14 · 2019: 8 · 2018: 3 · 2017: 9 · 2016: 9 · 2015: 3 · 2014: 11 · 2013: 12 · 2012: 12
- FWCI
- 1.91
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Current Opinion in Neurology (publishedVersion)
- PubMed (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- PubMed Central (acceptedVersion)
- Funders
- National Institute of Mental Health (K08MH081190, R01MH091861, L40 MH075270, K23MH091240, R25MH077823)
- National Institute of Neurological Disorders and Stroke (R01NS056276)
- National Center for Research Resources (UL1RR024139)
- Topics
- Social Sciences › Psychology › Clinical Psychology › Obsessive-Compulsive Spectrum Disorders
- Social Sciences › Psychology › Clinical Psychology › Stuttering Research and Treatment
- Health Sciences › Medicine › Neurology › Neurological disorders and treatments
- Keywords
- Tourette syndrome, tics, basal ganglia, neurobiology, rare variants, neuropsychiatric genetics, tic disorders, cognitive behavioral therapy, pharmacotherapy, non-pharmacological treatment
- MeSH terms
- Basal Ganglia, Tourette Syndrome, Histidine Decarboxylase, Humans, Tic Disorders
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
