Lu-lu Wu, MS; Marc N. Potenza, PhD, MD; Nan Zhou, PhD; Hedy Kober, PhD; Xin-hui Shi, MS; Sarah W. Yip, PhD; Jia-hua Xu, MS; Lei Zhu, MS; Rui Wang, MS; Guan-qun Liu, BS; Jin-tao Zhang, PhD
Background: Transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (dlPFC) may reduce substance use and other addictive behaviours. However, the cognitive mechanisms that underpin such effects remain unclear. Impaired inhibitory control linked to hypoactivation of the prefrontal cortex may allow craving-related motivations to lead to compulsive addictive behaviours. However, very few studies have examined whether increasing the activation of the dlPFC via anodal tDCS could enhance inhibitory control over addiction-related distractors. The current study aimed to enrich empirical evidence related to this issue.
Methods: Thirty-three males with Internet gaming disorder underwent active (1.5 mA for 20 minutes) and sham tDCS 1 week apart, in randomized order. We assessed inhibitory control over gaming-related distractors and craving pre- and post-stimulation.
Results: Relative to sham treatment, active tDCS reduced interference from gaming-related (versus non-gaming) distractors and attenuated background craving, but did not affect cue-induced craving.
Limitations: This study was limited by its relatively small sample size and the fact that it lacked assessments of tDCS effects on addictive behaviour. Future tDCS studies with multiple sessions in larger samples are warranted to examine the effects on addictive behaviours of alterations in addiction-related inhibitory control.
Conclusion: These findings demonstrate that stimulation of the dlPFC influences inhibitory control over addiction-related cues and addiction-related motivation. This is the first empirical study to suggest that enhanced inhibitory control may be a cognitive mechanism underlying the effects of tDCS on addictions like Internet gaming disorder. Our finding of attenuated background craving replicated previous tDCS studies. Intriguingly, our finding of distinct tDCS effects on 2 forms of craving suggests that they may have disparate underlying mechanisms or differential sensitivity to tDCS.
Clinical Trials No.: NCT03352973
Submitted Jul. 28, 2019; Revised Mar. 25, 2020; Accepted Jul. 10, 2020; Early-released Oct. 29, 2020
Affiliations: From the State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing, China (Wu, Xu, Shi, Zhu, Wang, Liu, Zhang); the Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA (Potenza, Kober, Yip); the Child Study Center, Yale University School of Medicine, New Haven, CT, USA (Potenza); the Department of Neuroscience, Yale University School of Medicine, Connecticut Mental Health Center, New Haven, Connecticut Council on Problem Gambling, Wethersfield, CT, USA (Potenza); the Connecticut Council on Problem Gambling, Wethersfield, CT, USA (Potenza); the Connecticut Mental Health Center, New Haven, CT, USA (Potenza); the Faculty of Education, Beijing Normal University, Beijing 100875, China (Zhou); and the Department of Psychology, Yale University School of Medicine, New Haven, CT, USA (Kober).
Competing interests: M. Potenza has consulted for and advised INSYS, Shire, RiverMend Health, Lakelight Therapeutics/Opiant and Jazz Pharmaceuticals; has received research support from the Mohegan Sun Casino and the National Center for Responsible Gaming; has participated in surveys, mailings or telephone consultations related to drug addiction, impulse control disorders or other health topics; and has consulted for law offices and gambling entities on issues related to impulse control or addictive disorders.
Contributors: L. Wu, M. Potenza, N. Zhou, H. Kober, S. Yip and J. Zhang designed the study. L. Wu, X. Shi, J. Xu, L. Zhu, R. Wang and G. Liu acquired the data, which L. Wu and J. Zhang analyzed. L. Wu, X. Shi, L. Zhu, R. Wang, G. Liu and J. Zhang wrote the article, which M. Potenza, N. Zhou, H. Kober, S. Yip, J. Xu and J. Zhang reviewed. All authors approved the final version to be published and can certify that no other individuals not listed as authors have made substantial contributions to the paper.
Funding: This study was supported by the National Natural Science Foundation of China (grant 31871122 and grant 31700966), the Project of Humanities and Social Sciences from the Ministry of Education in China (grant 15YJA190010) and the Open Research Fund of the State Key Laboratory of Cognitive Neuroscience and Learning (CNLZD1802). M. Potenza’s involvement was supported by the Connecticut Department of Mental Health and Addiction Services, the Connecticut Council on Problem Gambling and the National Center for Responsible Gaming. H. Kober’s involvement was supported by National Institute of Drug Abuse grants R01 DA042911, R01 DA043690, and P50 DA09241. The funding agencies did not have input into the content of the manuscript, and the views in the manuscript may not reflect those of the funding agencies.
Content licence: This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) licence, which permits use, distribution and reproduction in any medium, provided that the original publication is properly cited, the use is non-commercial (i.e. research or educational use), and no modifications or adaptations are made. See: https://creativecommons.org/licenses/by-nc-nd/4.0/
Correspondence to: J. Zhang, State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, 19 XinJieKouWai St., Haidian District, Beijing 100875, China; firstname.lastname@example.org