Evaluating the Effect of Methylphenidate on Intracortical Inhibition in Methamphetamine Abusers Comorbid With Attention Deficit Disorder With Hyperactivity(ADHD) in TMS Unit, Neurcognitive Lab, Iranian National Center for Addiction Studies (INCAS), in 2012. A Randomized, Controlled Trial

Previous studies using transcranial magnetic stimulation (TMS) with paired pulse protocols have shown that a conditioning TMS pulse applied to the human motor cortex changes the excitability of motor pathways from the motor cortex to spinal motorneurons. These effects depended on the stimulus intensity of both conditioning and test pulse and also the ISI). A characteristical sequence of inhibition (short interval cortical inhibition [SICI], GABA-Aerg), facilitation (intracortical facilitation [ICF]), and inhibition again (long interval cortical inhibition [LICI], GABA-Berg) is thought to be physiologically involved in motor control. Previous studies have also shown that neuronal inhibitory motor circuits are also disturbed in ADHD which will be restored by using methylphenidate. In this study the investigators sought to investigate if methamphetamine abuse (from the same chemical class of medications) will alter such effects of methylphenidate.