Different Modalities of Transcranial Magnetic Stimulation to Manage Schizophrenia

Objective: To analyze all current literature related to different transcranial magnetic stimulation (TMS) modalities in the management of schizophrenia symptoms and compare the main controversies in the outcome measures. Data Sources: A comprehensive search in Ovid MEDLINE, APA PsycINFO, and PubMed was conducted (1996 to present) to identify all articles using the search terms schizophrenia and single pulse TMS, schizophrenia and paired pulse TMS, schizophrenia and repetitive TMS, schizophrenia and deep TMS, and schizophrenia and TBS. Data Selection: Search results were limited to the English language and human subjects. Unrelated articles were excluded after the initial review. Nineteen studies fulfilled the eligibility criteria. These studies included 531 schizophrenia patients and 283 healthy controls. Results: While some adverse effects of TMS are reported, the process is generally considered safe. However, discrepancies exist regarding the length of the cortical silent period. The cortical silent period is thought to be mediated by γ-aminobutyric acid (GABA) receptors and is considered a useful probe to assess motor cortical inhibition. It is generally believed that patients with schizophrenia present changes in the cortical silent period due to GABA abnormalities. A few physiologic studies utilized TMS to study motor cortical excitability in schizophrenia and reported longer, and some shorter, cortical silent periods compared with healthy controls. Also, some studies reported a shorter cortical silent period for unmedicated versus medicated patients, while others reported no differences. Conclusion: TMS treatment is commonly reported to improve auditory hallucination in schizophrenia. Advantage of use of deep TMS over repetitive TMS, however, is controversial.