Non-invasive brain stimulation in craving disorders: evidence-based umbrella review

INTRODUCTION: The use of brain stimulation in the control of craving disorders is controversial, mainly in relation to the best target, technique, duration, frequency and parameters. Several meta-analyses have been published, and their data should be summarized to support the best evidence-based clinical practice. OBJECTIVE: To provide the best level of evidence for the use of non-invasive brain stimulation (NIBS) in the control of craving disorders. METHODS: Umbrella review registraded on Prospero (CRD42021239577), and conducted according to PRISMA recommendations. The methodological quality and evidence level were assessed through AMSTAR, AMSTAR rank and GRADE. RESULTS: A total of 81 meta-analyses were screened and the final analysis was made on 10 studies including 224 randomized clinical trials (RCTs) enrolling 5,555 patients. The main targets of stimulation were the right, left and bi-hemispheric dorsolateral prefrontal cortices. The studies used anodal tDCS, and high-frequency rTMS. The protocols with the larger effect sizes were anodal tDCS with 2mA, for 30 minutes over the right DLPFC (g=0.45; 95%CI 0.328-0.583; p<0.001), and high-frequency rTMS (10Hz), with 100% of the resting motor threshold, over the left DLPFC (g=1.116; 95%CI 0.597-1.634; p<0.001). The quality of evidence ranged from very low to moderate because of inconsistencies mainly due to sample heterogeneity. CONCLUSION: The results of 10 meta-analyses assessing the efficacy of NIBS in the control of craving disorders are robust regarding the effect sizes and provide evidence that bi-hemispheric tDCS and high-frequency rTMS over the DLPFC are effective in the control of craving disorders. However, the evidence level is from low to moderate.