Several personality disorders involve pathological behaviors that violate social norms, commonly held expectations about what ought to be done in specific situations. These symptoms usually emerge early in development, are persistent and hard to treat, and are often ego-syntonic. Here I present some recent brain stimulation studies suggesting that pathological changes in different aspects of norm-compliant behavior reflect dysfunctions of brain circuits involving distinct prefrontal brain areas. One set of studies shows that transcranial direct current stimulation of the right lateral prefrontal cortex changes the behavioral sensitivity to social incentives for norm-compliant behavior. Crucially, social norm compliance in response to such incentives could even be increased during excitatory stimulation, demonstrating that the affected neural process is a biological prerequisite for appropriate reaction to social signals that trigger norm compliance. In another set of studies, we show that stimulation of a different (more dorsal) part of the right prefrontal cortex enhances honesty in a realistic setting where participants had the opportunity to cheat for real monetary gains. Interestingly, these stimulation-induced increases in both socially cued or purely voluntary norm compliance were not linked to changes in other aspects of decision- making (such as risk or impatience), and they did not reflect changes in beliefs about what is appropriate behavior. These results suggest that disorders of distinct brain circuits may causally underlie egosyntotic changes in norm-compliant behavior. This raises the tantalizing possibility that pathologies of norm-compliant behavior may be ameliorated by interventions targeting the function of these brain circuits.

Keywords:
Brain stimulation, Ego-syntonic behavior, Personality disorders, Social norms, Transcranial direct current stimulation
1.
Elster J: The Cement of Society: A Study of Social Order, ed 1. Cambridge, Cambridge University Press, 1989.
2.
Sober E, Wilson DS: Unto others: The Evolution and Psychology of Unselfish Behavior, ed 1. Cambridge, Harvard University Press, 1999.
3.
Fischbacher U, Gächter S, Fehr E: Are people conditionally cooperative? Evidence from a public goods experiment. Econ Lett 2001; 71: 397–404.
4.
Boyd R, Gintis H, Bowles S, Richerson PJ: The evolution of altruistic punishment. Proc Natl Acad Sci USA 2003; 100: 3531–3535.
5.
Fischbacher U, Forsythe R, Horowitz HL, Savin NE, Sefton M: Fairness in simple bargaining experiments. Games Econ Behav 1994; 6: 347–369.
6.
Hare RD, Hart SD, Harpur, TJ: Psychopathy and the DSM-IV criteria for antisocial personality disorder. J Abnorm Psychol 1991; 100: 391–398.
7.
Bach B, Sellbom M, Kongerslev M, Simonsen E, Krueger RF, Mulder R: Deriving ICD-11 personality disorder domains from DSM-5 traits: initial attempt to harmonize two diagnostic systems. Acta Psychiatr Scand 2017; 136: 108–117.
8.
Loeber R, Burke JD, Lahey BB: What are adolescent antecedents to antisocial personality disorder? Crim Behav Ment Health 2002; 12: 24–36.
9.
Compton WM, Conway KP, Stinson FS, Colliver JD, Grant, BF: Prevalence, correlates, and comorbidity of DSM-IV antisocial personality syndromes and alcohol and specific drug use disorders in the United States: results from the National Epidemiologic Survey on Alcohol and Related Conditions. J Clin Psychiatry 2005; 66: 677–685.
10.
Coid J, Yang M, Tyrer P, Roberts A, Ullrich S: Prevalence and correlates of personality disorder in Great Britain. Br J Psychiatry 2006; 188: 423–431.
11.
Carey G, Goldman D: The genetics of anti-social behaviour; in Stoff DM, Breiling J, Maser JD (eds): Handbook of Antisocial Behavior. Chichester, Wiley, 1997, pp 243–250.
12.
Goodman M, New A, Siever L: Trauma, genesis, and the neurobiology of personality disorders. Ann NY Acad Sci 2004; 1032: 104–116.
13.
Slutske WS, Heath AC, Dinwiddie SH, et al: Modeling genetic and environmental influences in the etiology of conduct disorder. A study of 2,682 adult twin pairs. J Abnorm Psychol 1997; 106: 266–279.
14.
Stouthamer-Loeber M, Loeber R, Wei E, et al: Risk and promotive effects in the explanation of persistent serious delinquency in boys. J Consult Clin Psychol 2002; 70: 111–123.
15.
Andrews D, Zinger I, Hoge RD, et al: Does correctional treatment work? A clinically relevant and psychologically informed meta-analysis. Criminology 1990; 28: 369–404.
16.
Levitt SD, List JA: What Do laboratory experiments measuring social preferences reveal about the real world? J Econ Perspect 2007; 21: 153–174.
17.
Ruff CC, Ugazio G, Fehr E: Changing social norm compliance with noninvasive brain stimulation. Science 2013; 342: 482–484.
18.
Spitzer M, Fischbacher U, Herrnberger B, Grön G, Fehr E: The neural signature of social norm compliance. Neuron 2007; 56: 185–196.
19.
Nitsche MA, Paulus W: Excitability changes induced in the human motor cortex by weak transcranial direct current stimulation. J Physiol 2000; 527: 633–639.
20.
Greene JD, Paxton JM: Patterns of neural activity associated with honest and dishonest moral decisions. Proc Natl Acad Sci USA 2009; 106: 12506–12511.
21.
Maréchal MA, Cohn A, Ugazio G, Ruff CC: Increasing honesty in humans with noninvasive brain stimulation. Proc Natl Acad Sci USA 2017; 114: 4360–4364.
22.
Koenigs M: The role of prefrontal cortex in psychopathy. Rev Neurosci 2012; 23: 253–262.
23.
Szczepanski SM, Knight RT: Insights into human behavior from lesions to the prefrontal cortex. Neuron 2014; 83: 1002–1018.
24.
Diamond A: Normal development of prefrontal cortex from birth to young adulthood: cognitive functions, anatomy, and biochemistry; in Stuss D, Knight R (eds): Principles of Frontal Lobe Function. New York, Oxford University Press, 2002, pp 466–503.
25.
Hosking JG, Kastman EK, Dorfman HM, Samanez-Larkin GR, Baskin-Sommers A, Kiehl KA, Newman JP, Buckholtz JW: Disrupted prefrontal regulation of striatal subjective value signals in psychopathy. Neuron 2017; 95: 221–231.
26.
Contreras-Rodríguez O, Pujol J, Batalla I, Harrison BJ, Soriano-Mas C, Deus J, López-Solà M, Macià D, Pera V, Hernández-Ribas R, Pifarré J, Menchón JM, Cardoner N: Functional connectivity bias in the prefrontal cortex of psychopaths. Biol Psychiatry 2015; 78: 647–655.
27.
Knoch D, Pascual-Leone A, Meyer K, Treyer V, Fehr E: Diminishing reciprocal fairness by disrupting the right prefrontal cortex. Science 2006; 314: 829–832.
28.
Strang S, Gross J, Schuhmann T, Riedl A, Weber B, Sack AT: Be nice if you have to – the neurobiological roots of strategic fairness. Soc Cogn Affect Neurosci 2015; 10: 790–796.
29.
Driver J, Blankenburg F, Bestmann S, Vanduffel W, Ruff CC: Concurrent brain-stimulation and neuroimaging for studies of cognition. Trends Cogn Sci 2009; 13: 319–327.
30.
Steinbeis N, Bernhardt BC, Singer T: Impulse control and underlying functions of the left DLPFC mediate age-related and age-independent individual differences in strategic social behavior. Neuron 2012; 73: 1040–1051.
31.
Zhu L, Jenkins AC, Set E, Scabini D, Knight RT, Chiu PH, King-Casas B, Hsu M: Damage to dorsolateral prefrontal cortex affects trade-offs between honesty and self-interest. Nat Neurosci 2014; 17: 1319–1321.
© 2018 S. Karger AG, Basel
2018
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.