Treatment of Negative Symptoms of Schizophrenia With Transcranial Magnetic Stimulation (TMS)

Most treatments for schizophrenia are helpful in treating positive symptoms (e.g. hallucinations), whereas negative symptoms (e.g. low social drive) are only partially responsive to medication. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive way of stimulating the brain that has been FDA approved for the treatment of depression and has shown promise in schizophrenia. In rTMS therapy, a device called a "magnetic stimulator" provides electrical energy to a magnetic coil that delivers a magnetic field. When the coil is placed against the surface of the head, the magnetic field can cause parts of the brain to either increase or decrease in activity, depending on how quickly the magnetic pulses are delivered. This study is designed to test whether high-frequency rTMS delivered to an area near the front of the head, called the dorsolateral prefrontal cortex, can improve the "negative symptoms" of schizophrenia, which include decreased thinking, difficulty motivating, and social withdrawal. Participation in the first phase of the study consists of sessions lasting about 45 minutes per day, 5 days a week, for 4 weeks. Twenty-four subjects will be randomly assigned to receive four weeks of either active (real) rTMS or inactive (sham) rTMS. Patients will receive magnetic resonance imaging (MRI) of their brains to help locate where the rTMS should be applied. Symptoms will be rated at baseline, during the rTMS course, and at the end of the 4 weeks. Patients who do not meet response criteria after the four weeks of the randomized phase will be offered active (real) daily rTMS for an additional four weeks in the open phase of the study. All patients will have two monthly repeat assessments after their last rTMS session to examine the persistence of benefit. We will also collect measures of motor cortex excitability (performed with single pulse TMS) at baseline, at the end of the randomized and, if applicable, the open study phase, and at each of the two follow-up assessments to determine whether changes in these measures correlate with clinical improvement. In addition, we will look at brain dynamics using electroencephalography (EEG) pre- and post-rTMS in the first and last sessions of each study phase. We will also assess the effects of rTMS on cigarette use, as schizophrenia patients are known to have increased prevalence of nicotine dependence. There is also preliminary evidence that high frequency rTMS to the left DLPFC decreases cigarette smoking.