IRCT2014031611234N2 IRCT 2015-01-27 Cognitive Sciences and Technology Council Cumulative effects of transcranial direct current stimulation on meth craving tDCS Evaluating long-term therapeutic effects of transcranial direct current stimulation with most efficient montage over the dorsolateral prefrontal cortex targeting craving in methamphetamine abusers; Two Consecutive Randomized Clinical Trials 2015-04-21 anticipated 180 Complete https://irct.ir/trial/11532 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment. 2-3 Methamphetamine dependency. Intervention 1: Direct current is delivered from a battery-driven, constant current stimulator (ActivaDoseII. Iontophoresis Delivery Unit, P/N00148-Rev A, ActivaTek, Inc. Salt Lake City UT 84119 USA) and transferred by a pair of 5×7 (35cm2) electrodes. In the first phase, 120 participants will be randomly assigned to a control group (n = 20) or a 5-intervention groups (n = 20 per group).Each of the intervention groups will receive one specific montages of real stimulation (1. Right anode, cathode extra-cephalic 2. Left anode, cathode extra-cephalic 3. Right anode, Left cathode 4 left anode, right cathode; 5. Left and right anode, cathode extra-cephalic), and the control group will receive sham stimulation. The tDCS Protocol for all groups will be 2mA during 20 minutes. The Immediate and cue induced craving will be assessed before and after stimulation by VAS, DDQ and CCICT, respectively. Intervention 2: In this study, control group will receive sham transcranial direct current stimulation (tDCS). For sham stimulation, the anode and cathode electrodes will have same position with the one of the intervention groups’ montages. However, the stimulator is ramped-up to 2 mA in 30s, then gradually ramped-down to 0 mA over the period of 1 minute, and then turned off but the electrodes will be on the scalp for 20 minutes and subjects will not be informed that the device is turned off.