title: Modulation of risk-taking in marijuana users by transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC).
abstract: Cognitive deficits that are reported in heavy marijuana users (attention, memory, affect perception, decision-making) appear to be completely reversible after a prolonged abstinence period of about 28 days. However, it remains unclear whether the reversibility of these cognitive deficits indicates that (1) chronic marijuana use is not associated with long-lasting changes in cortical networks or (2) that such changes occur but the brain adapts to and compensates for the drug-induced changes. Therefore, we examined whether chronic marijuana smokers would demonstrate a differential pattern of response in comparison to healthy volunteers on a decision-making paradigm (Risk Task) while undergoing sham or active transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC). Twenty-five chronic marijuana users who were abstinent for at least 24h were randomly assigned to receive left anodal/right cathodal tDCS of DLPFC (n=8), right anodal/left cathodal tDCS of DLPFC (n=9), or sham stimulation (n=8); results on Risk Task during sham/active tDCS were compared to healthy volunteers from a previously published dataset. Chronic marijuana users demonstrated more conservative (i.e. less risky) decision-making during sham stimulation. While right anodal stimulation of the DLPFC enhanced conservative decision-making in healthy volunteers, both right anodal and left anodal DLPFC stimulation increased the propensity for risk-taking in marijuana users. These findings reveal alterations in the decision-making neural networks among chronic marijuana users. Finally, we also assessed the effects of tDCS on marijuana craving and observed that right anodal/left cathodal tDCS of DLPFC is significantly associated with a diminished craving for marijuana.
authors: Cognitive Neuroscience Laboratory and Developmental Disorders Program, Center for Health and Biological Sciences, Mackenzie Presbyterian University, Rua Piaui, 181, 10 Andar, Sao Paulo, SP 01241-001, Brazil. boggio@mackenzie.br
authors: Paulo S
authors: PS
authors: Boggio
authors: Soroush
authors: S
authors: Zaghi
authors: Ana Beatriz
authors: AB
authors: Villani
authors: Shirley
authors: S
authors: Fecteau
authors: Alvaro
authors: A
authors: Pascual-Leone
authors: Felipe
authors: F
authors: Fregni
mesh_terms: D001288:Attention / Q000187:drug effects / Q000502:physiology; D002188:Cannabis; D003657:Decision Making / Q000187:drug effects / Q000502:physiology; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008385:Marijuana Smoking / Q000523:psychology*; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000502:physiology*; D012306:Risk; D012309:Risk-Taking