@article{b51dad7cbf374bd5af40e3fd1878b849,
title = "Disorders of compulsivity: A common bias towards learning habits",
abstract = "Why do we repeat choices that we know are bad for us? Decision making is characterized by the parallel engagement of two distinct systems, goal-directed and habitual, thought to arise from two computational learning mechanisms, model-based and model-free. The habitual system is a candidate source of pathological fixedness. Using a decision task that measures the contribution to learning of either mechanism, we show a bias towards model-free (habit) acquisition in disorders involving both natural (binge eating) and artificial (methamphetamine) rewards, and obsessive-compulsive disorder. This favoring of model-free learning may underlie the repetitive behaviors that ultimately dominate in these disorders. Further, we show that the habit formation bias is associated with lower gray matter volumes in caudate and medial orbitofrontal cortex. Our findings suggest that the dysfunction in a common neurocomputational mechanism may underlie diverse disorders involving compulsion.",
author = "V. Voon and K. Derbyshire and C. R{\"u}ck and Irvine, {M. A.} and Y. Worbe and J. Enander and Schreiber, {L. R.N.} and C. Gillan and Fineberg, {N. A.} and Sahakian, {B. J.} and Robbins, {T. W.} and Harrison, {N. A.} and J. Wood and Daw, {N. D.} and P. Dayan and Grant, {J. E.} and Bullmore, {E. T.}",
note = "Funding Information: ETB is employed part-time by the University of Cambridge and part-time by GSK PLC and is a shareholder of GSK. TWR is a consultant for Cambridge Cognition, Eli Lilly, GSK, Merck, Sharpe and Dohme, Lundbeck, Teva and Shire Pharmaceuticals. He is or has been in receipt of research grants from Lundbeck, Eli Lilly and GSK and is an editor for Springer-Verlag (Psychopharmacology). JWD is a consultant for Boehringer Ingelheim and has received grants from this company. JEG has received research grant support from NIDA, NCRG, Psyadon Pharmaceuticals and Transcept Pharmaceuticals. He has also received royalties from American Psychiatric PublishingA, Oxford University Press, Norton, and McGraw Hill Publishers. The remaining authors report no conflicts of interest. Funding Information: We would like to thank the subjects who participated in the study in Cambridge and staff and clients at the PRIDE Institute of Minnesota for their invaluable assistance with the study. This study was funded by the WT fellowship grant for VV (093705/Z/ 10/Z) and Cambridge NIHR Biomedical Research Centre. VV and NAH are Wellcome Trust (WT) intermediate Clinical Fellows. YW is supported by the Fyssen Fondation and MRC Studentships. PD is supported by the Gatsby Charitable Foundation. JEG has received grants from the National Institute of Drug Abuse and the National Center for Responsible Gaming. TWR and BJS are supported on a WT Programme Grant (089589/Z/09/Z). The BCNI is supported by a WT and MRC grant. Publisher Copyright: {\textcopyright} 2015 Macmillan Publishers Limited.",
year = "2015",
month = mar,
day = "12",
doi = "10.1038/mp.2014.44",
language = "English (US)",
volume = "20",
pages = "345--352",
journal = "Molecular Psychiatry",
issn = "1359-4184",
publisher = "Nature Publishing Group",
number = "3",
}