Bethesda Marriott Hotel, Bethesda, MD
March 16, 2004
Maria D. Majewska, Ph.D., Division of Pharmacotherapies and Medical Consequences of Drug Abuse, and The Translationally Oriented Approaches, Devices and Strategies Workgroup
David Thomas, Ph.D., Division of Basic Neuroscience and Behavioral Research, and The Translationally Oriented Approaches, Devices and Strategies Workgroup
Meeting Purpose and Intent
Finding practical applications of new research technologies is of interest to NIDA. Transcranial Magnetic Stimulation (TMS) is an exciting neurotechnology, used as a diagnostic and therapeutic tool for the treatment of various neuro-psychiatric disorders. The purpose of this meeting was to review the current state of the art of TMS utilization in psychiatry and neurology and to discuss its potential in the treatment of substance use disorders.
TMS produces rapid and selective stimulation or inhibition of chosen superficial brain regions. It has been found to be safe and effective in the treatment of depression, pain, and to have a potential in the treatment of post-traumatic stress disorder, attention deficit disorder, obsessive compulsive disorder, symptoms of schizophrenia, and memory impairments.
This technology also has a great promise as a potential treatment for drug abuse. Brain imaging studies documented lateralized effects of stimulants on human brain and particular involvement of the right cerebral hemisphere (Neuron, 19:591-611, 1997; Am. J. Psychiat. 1556: 19-26, 1999). TMS may offer a unique therapeutic tool for the treatment of drug/cocaine/stimulant dependence. By allowing site and region-specific stimulation or inhibition of different brain areas, it may block craving or compensate for neuronal deficits in drug addicts, facilitating recovery from drug dependence. Moreover, drug abuse has been linked to a hypoactive prefrontal cortex, which may be the neurophysiological substrate of the decreased cognitive control related to drug abuse behaviors. Increasing prefrontal activity in drug abusers is a potential treatment goal and it can be achieved with TMS technique. Indeed, unilateral prefrontal TMS can increase performance on cognitive tasks (Neurology, 56:526-528, 2001).
This meeting was intended to review the data on utilization of TMS in neurology and psychiatry with speakers selected based on their expertise. They included both extramural and intramural scientists. The discussions were oriented toward prospective use of TMS in the treatment of drug dependence or its psychoneurological consequences.
Another meeting intention was to inform NIDA staff on the potential of TMS as it relates to drug abuse research and treatment, and to develop a new initiative that encourages research in this area. The NIDA Translationally Oriented Approaches, Devices and Strategies Workgroup was involved in planning this meeting.
The speakers presented a comprehensive review of data on utilization of TMS in psychiatry and neurology, with reference to its potential application to the field of drug abuse. Dr. Majewska opened the conference by outlining the rationale for evaluation of TMS in the treatment of substance use disorders (SUD) and suggested potential neurobiological substrates for such treatments, such as craving or metabolic deficits in the prefrontal cortex. Dr. Volkow gave an overview of NIDA’s mission to discover safe and effective therapies for the treatment of SUD and presented her imaging data on anatomical and functional changes observed in brains of chronic drug abusers, which could be targets for TMS therapy. Dr. Wassermann discussed technical aspects, safety and neurophysiological effects of neurotechnologies such as TMS and transcranial direct current stimulation (TDCS) on alteration of human behaviors. Dr. Boutros presented data on utilization of TMS for the measurement of cortical excitability, which revealed compensatory increase of cortical inhibition in abstinent cocaine-dependent individuals, which may contribute to psychiatric abnormalities in this population. Dr. Pascual-Leone critically reviewed the findings on diagnostic and therapeutic utility of TMS in psychiatry. He recommended a combination of TMS with EEG, which together may allow for more precise neuroanatomical evaluation of neurological dysfunctions, or stimulation of specific cortical targets in patients. Dr. George presented his pioneering method, which allows performing TMS within an fMRI scanner. This combined TMS/fMRI technique, although with current limitations, has much potential for research on simultaneous brain stimulation with TMS and functional/anatomical detection of brain changes, induced by this stimulation. Dr. Avery showed data on the meta-analysis of 4 studies evaluating efficacy of rTMS in the treatment of depression: The analysis showed, 2 weeks after the treatment, a marked reduction of depression score in 34% of TMS-treated patients, compared to 7% in sham treated, and 25% of remission in TMS group, compared to 3% in sham treated. Of the TMS responders, 66% did not relapse to depression 6 months after the treatment. Dr Lisanby discussed a possibility of utilizing TMS under anesthesia as a safer alternative to electroconvulsive therapy (ECT) to treat various brain disorders such as depression, or to stimulate the regenerative processes in the brain, which may have application for the treatment of psychoneurological deficits in SUDs. Dr. Marc Hallett spoke about utilization of TMS in treating movement disorders, mild epilepsy and pain. This technique might be useful in treating dystonia and pain, but might worsen performance in complex movement disorders. Dr. Grafman discussed the potential of TMS in modulating learning and memory, and presented data showing that depending on the conditions, TMS might facilitate or worsen these functions. Finally Dr. Greenberg spoke about neuroanatomical and functional parallels between refractory obsessive-compulsive disorder (OCD) and SUD and showed preliminary data suggesting utility of TMS in normalizing abnormal cortical activity in OCD.
The general impression of conference participants was that TMS is a promising and safe neurotechnique, whose utility in the treatment of SUDs should be rigorously examined. If effective, it could become an easy to use, inexpensive therapeutic tool in psychiatric practice.
A new Program Announcement entitled "COMPLEMENTARY AND ALTERNATIVE MEDICINE FOR SUBSTANCE RELATED DISORDERS", which invites research on TMS (among other non-conventional therapies) in the treatment of SUDD, has been developed.
- M.D. Majewska (NIDA) - Introduction, meeting objectives
- N. Volkow (NIDA Director) - Imaging of drug addicted brain: craving and long term functional changes
- E. Wassermann (NINDS) - Potential transcranial stimulation treatments for drug addiction: basic mechanisms
- N. Boutros (Yale U.) - TMS in cocaine dependence
- A. Pascual-Leone (Harvard MS) - TMS in neuropsychiatry and neurology
- M. George (MUSC) - Combining TMS and MRI in neuropsychiatry
- D. Avery (U Washington) - TMS in depression, meta-analysis
- S. Lisanby (Columbia U) - TMS as ECT in depression
- M. Hallett (NINDS) - TMS in neurology and neuroregeneration
- J. Grafman (NINDS) - rTMS can modulate learning and memory: urge the purge
- B. Greenberg (Brown U) - Deep brain stimulation in neurology