Lack of Effects of Extended Sessions of Transcranial Direct Current Stimulation (tDCS) Over Dorsolateral Prefrontal Cortex on Craving and Relapses in Crack-Cocaine Users

Abstract

Background: Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) has been investigated as additional therapeutic tool for drug use disorder. In a previous study, we showed that five sessions of tDCS applied bilaterally over the dorsolateral prefrontal cortex (dlPFC) reduced craving to the use of crack-cocaine in inpatients from a specialized clinic. In the present study, we examine if an extended number of sessions of the same intervention would reduce craving even further and affect also relapses to crack-cocaine use.Methods: A randomized, double-blind, sham-controlled, clinical trial with parallel arms was conducted (https://clinicaltrials.gov/ct2/show/NCT02091167). Crack-cocaine patients from two private and one public clinics for treatment of drug use disorder were randomly allocated to two groups: real tDCS (5 cm × 7 cm, 2 mA, for 20 min, cathodal over the left dlPFC and anodal over the right dlPFC, n = 19) and sham-tDCS (n = 16). Real or sham-tDCS was applied once a day, every other day, in a total of 10 sessions. Craving was monitored by a 5-item obsessive compulsive drinking scale once a week (one time before, three times during and once after brain stimulation) over about 5 weeks and relapse was monitored after their discharge from clinics for up to 60 days.Results: Craving scores progressively decreased over five measurements in both sham- and real tDCS groups. Corrected Hedges’ within-group (initial and final) effect sizes of craving scores were of 0.77 for the sham-tDCS and of 0.97 for the real tDCS group. The between-groups effect size was of 0.34, in favor of the real tDCS group over sham-tDCS group. Relapse rates were high and quite similar between groups in the 30- and 60-days follow-up after discharge from the hospital.Conclusion: Extended repetitive bilateral tDCS over the dlPFC had no add-on effects over regular treatment when considering craving and relapses to the crack-cocaine use in a sample of crack-cocaine patients with severe use disorder. Different tDCS montages targeting other cortical regions and perhaps additional extension of sessions need to be investigated to reach more efficiency in managing craving and relapses to crack-cocaine use.

The Effect of Transcranial Direct Current Stimulation on Relapse, Anxiety, and Depression in Patients With Opioid Dependence Under Methadone Maintenance Treatment: A Pilot Study

“…In our study, applying the right anodal active tDCS, which has more evidence in reducing craving in different studies, could not significantly reduce the relapse rate in patients with opioid dependence disorder enrolled MMT program (Klauss et al, 2018;Taremian et al, 2019). However, after seventh session of tDCS, the intervention group had lower relapse rate compared to the sham group.…”

Repeated stimulation of the dorsolateral-prefrontal cortex improves executive dysfunctions and craving in drug addiction: A randomized, double-blind, parallel-group study

“…cocaine, tobacco), recent studies have examined the effects of repeated tDCS sessions over the DLPFC [37e39]. All of these studies, except for Klauss et al [37], observed increased effects of extended stimulation on reduced craving in patients, although none of them have examined executive dysfunctions.…”

“…However, the number of studies investigating the effect of neuromodulation on the cognitive processes involved in addiction remains limited [11], precluding any firm conclusion about cognition-improving effects and clinical efficacy [11,41]. The fact that most other studies on drug addictions have targeted craving as the main outcome parameter [37,38] or applied short durations of DLPFC stimulation, which may not be clinically effective [42,43], makes it furthermore difficult to come to definite assumptions. In order to evaluate the potential of tDCS in addiction, including its effects on cognitive deficits, trials with longer courses of stimulation, as suggested by recent findings [42], inclusion of objective neurophysiological and cognitive measures, and monitoring of long-term outcomes would be helpful [11].…”

Transcranial electrical and magnetic stimulation (tES and TMS) for addiction medicine: A consensus paper on the present state of the science and the road ahead

“…Acute multiple sessions of tDCS stimulation protocols, typically related to facilitative effects on cortical excitability (Nitsche and Paulus, 2000;Paulus, 2003), have been associated with a reduction of spontaneous (Batista et al, 2015;Klauss et al, 2018b), and cue-induced craving (Boggio et al, 2009;Fregni et al, 2008;Gorelick et al, 2014) when applied over the prefrontal cortex. However, there was no effect on spontaneous craving when stimulation sessions were extended (Klauss et al, 2018a). Similarly, rTMS protocols at high frequency (5-25 Hz) have typically been used to excite cortical neurons and elicit LTP-like effects.…”