Disorders of compulsivity: a common bias towards learning habits.
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.
1] Department of Psychiatry, University of Cambridge, Cambridge, UK [2] Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK [3] Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK.
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V
Voon
1] Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA [2] Department of Psychiatry and Behavioural Neuroscience, University of Chicago, Chicago, IL, USA.
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Derbyshire
Division of Psychiatry, Department of Clinical Neurosciences, Karolinska Institute, Stockholm, Sweden.
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C
Rück
Department of Psychiatry, University of Cambridge, Cambridge, UK.
M A
MA
Irvine
Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.
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Y
Worbe
Division of Psychiatry, Department of Clinical Neurosciences, Karolinska Institute, Stockholm, Sweden.
J
J
Enander
Department of Psychiatry, University of Minnesota, Minneapolis, MN, USA.
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LR
Schreiber
1] Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK [2] Department of Psychology, University of Cambridge, Cambridge, UK.
C
C
Gillan
Department of Psychiatry, University of Hertfordshire, Hertfordshire, UK.
N A
NA
Fineberg
1] Department of Psychiatry, University of Cambridge, Cambridge, UK [2] Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK.
B J
BJ
Sahakian
1] Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK [2] Department of Psychology, University of Cambridge, Cambridge, UK.
T W
TW
Robbins
Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, University of Sussex, Brighton, UK.
N A
NA
Harrison
Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK.
J
J
Wood
Center for Neural Science and Department of Psychology, New York University, New York, NY, USA.
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ND
Daw
Gatsby Computational Neuroscience Unit, University College London, London, UK.
P
P
Dayan
Department of Psychiatry and Behavioural Neuroscience, University of Chicago, Chicago, IL, USA.
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JE
Grant
1] Department of Psychiatry, University of Cambridge, Cambridge, UK [2] Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK [3] Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK [4] NIHR Cambridge Biomedical Research Centre, Cambridge, UK.
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Bullmore
D000328:Adult; D000465:Algorithms; D015982:Bias; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D002755:Choice Behavior; D003198:Computer Simulation; D005260:Female; D006184:Habits; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007858:Learning / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000473:pathology / Q000523:psychology; D009771:Obsessive-Compulsive Disorder / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D012044:Regression Analysis; D012201:Reward; D019966:Substance-Related Disorders / Q000150:complications / Q000473:pathology / Q000523:psychology; D011795:Surveys and Questionnaires; D055815:Young Adult