Article

Modulation of risk-taking in marijuana users by transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex (DLPFC)

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.
Drug and alcohol dependence (Impact Factor: 3.42). 12/2010; 112(3):220-5. DOI: 10.1016/j.drugalcdep.2010.06.019
Source: PubMed

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.

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Available from: Alvaro Pascual-Leone, Dec 19, 2013
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    • "Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique that induces polarity-dependent alterations of cortical excitability (Nitsche and Paulus, 2000; Nitsche et al., 2003, 2007, 2008). Modulation of dlPFC functions with tDCS has been shown to reduce craving for smoking (Fregni et al., 2008a), marijuana (Boggio et al., 2010), and food in healthy subjects (Fregni et al., 2008b). We thus hypothesized that tDCS over the dlPFC might be a promising therapeutic approach to treat drug dependence. "
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    ABSTRACT: transcranial Direct Current Stimulation (tDCS) over the dorsolateral prefrontal cortex (dlPFC) has been shown to be clinically useful in the treatment of drug addiction. We conducted a double-blind randomized clinical trial aiming to assess the effects of bilateral dlPFC tDCS (left cathodal/right anodal) on crack-cocaine addiction. We defined craving as the primary outcome, and other clinical measurements, including depressive and anxiety symtoms, and quality of life, as secondary outcomes. 17 male crack-cocaine users (mean age 30.4 ± 9.8 SD) were randomized to receive five sessions of active tDCS (2 mA, 35 cm(2), for 20 minutes), every other day, and 19 males (mean age 30.3 ± 8.4 SD) to receive sham-tDCS (placebo), as control group. Craving scores were significantly reduced in the tDCS group after treatment when compared to sham-tDCS (p = 0.028) and to baseline values (p = 0.003), and decreased linearly over four weeks (before, during and after treatment) in the tDCS group only (p = 0.047). Changes of anxiety scores towards increase in the sham-tDCS and decrease in the tDCS group (p = 0.03), and of the overall perception of quality of life (p = 0.031) and of health (p = 0.048) towards decrease in the sham-tDCS group and increase in the tDCS group, differed significantly between groups. Repetitive bilateral tDCS over the dlPFC reduced craving to crack-cocaine use, decreased anxiety and improved quality of life. We hypothesize that tDCS effects may be associated with increased pre-frontal processing and regulation of craving behavior. © The Author 2015. Published by Oxford University Press on behalf of CINP.
    Full-text · Article · Jun 2015 · The International Journal of Neuropsychopharmacology
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    • "6. Defining objectively the monitoring measures: As it can be seen in Tables 2 and 3, drug craving is the most common cognitive target and assessment measure in addiction and NIBS studies. However, there is an increasing trend for targeting other components including risk-taking behavior (Boggio et al., 2010;Fecteau et al., 2014;Gorini et al., 2014), relapse (daSilva et al., 2013;Klauss et al., 2014), drug consumption (Boggio et al., 2009;Fecteau et al., 2014;Meng et al., 2014), and attentional bias (Meng et al., 2014). Self-report questionnaires are subjective, and therefore prone to risk of assessment bias. "
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    ABSTRACT: Addiction is a chronic relapsing brain disease with significant economical and medical burden on the societies but with limited effectiveness in the available treatment options. Better understanding of the chemical, neuronal, regional, and network alterations of the brain due to drug abuse can ultimately lead to tailoring individualized and more effective interventions. To this end, employing new assessment and intervention procedures seems crucial. Noninvasive brain stimulation (NIBS) techniques including transcranial electrical and magnetic stimulations (tES and TMS) have provided promising opportunities for the addiction medicine in two main domains: (1) providing new insights into neurochemical and neural circuit changes in the human brain cortex and (2) understanding the role of different brain regions by using NIBS and modulating cognitive functions, such as drug craving, risky decision making, inhibitory control and executive functions to obtain specific treatment outcomes. In spite of preliminary positive results, there are several open questions, which need to be addressed before routine clinical utilization of NIBS techniques in addiction to medicine, such as how to account for interindividual differences, define optimal cognitive and neural targets, optimize stimulation protocols, and integrate NIBS with other therapeutic methods. Therefore, in this chapter we revise the available literature on the use of NIBS (TMS and tES) in the diagnostic, prognostic, and therapeutic aspects of the addiction medicine.
    Full-text · Article · Jun 2015 · Progress in brain research
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    • "Additionally, several studies have shown that tDCS of the DLPFC can reduce the craving for different types of substance, including alcohol, nicotine, drugs, and food (Boggio et al., 2009a, 2008; Fregni et al., 2008a). Other studies have observed a decrease in risk-taking in healthy volunteers compared with marijuana users (Boggio et al., 2010), a reduction in appetite for risk during ambiguous decisionmaking and a decrease in risk-taking in a risk task (Fecteau et al., 2007a, 2007b) during right anodal/left cathodal stimulation of the right DLPFC. However, the effect of tDCS on the IFG has not previously been reported. "

    Full-text · Dataset · Apr 2015
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