This study purpose is to perform a pilot mechanistic trial repetitive transcranial magnetic stimulation (rTMS) clinical trial in 34 people with schizophrenia (Sz). The trial will evaluate whether inhibitory 1 Hertz (Hz) rTMS targeting motor cortex can increase brain inhibition reflected in a decrease in the short-interval intracortical inhibition (SICI) score from pre-to-post-treatment. We will also collect preliminary data on the effect of rTMS on the resting functional connectivity of the motor cortex and other brain regions and the relationship of change in SICI to change in cognitive performance

This study is a randomized double blind clinical trial being funded by the National Institute of Mental Health (NIMH). The primary aim is to estimate feasibility and tolerability of a 5-day, 1Hz rTMS intervention in 34 participants with schizophrenia. A secondary aim is to assess target engagement by investigating whether 1 Hz rTMS applied to motor cortex can enhance intracortical inhibition in participants with schizophrenia. The participants with Sz will be randomized in a 1:1 ratio to either active 1Hz rTMS or sham 1Hz rTMS. We do not necessarily anticipate a statistically significant difference between treatment groups, given our limited sample size. Rather, we are focused on generating effect size estimates that will help us determine whether and how to proceed to the next phase of research and a future R01 submission. We will explore the relationship between change in SICI score (pre-to-post-treatment) and total scores of clinical scales (Fagerstrom nicotine dependence, the brief psychiatric rating scale and the brief negative symptoms scale) and medication dose and type. We will also collect preliminary data on the effect of rTMS on the resting state functional connectivity of the motor cortex with other brain regions, and the change performance on cognitive tasks (i.e., stop signal reaction time, spatial working memory) from pre-to-post-treatment.

Inclusion Criteria:

1. Age 18-45 years
2. Male or Female
3. Able to participate in the informed consent process and provide voluntary informed consent.
4. A Diagnostic and Statistical Manual of Mental Disorders 5 (DSM-5) diagnosis of schizophrenia documented by the Structured Clinical Interview for DSM-5 (SCID-5)

Exclusion Criteria:

1. A history of a DSM-5 substance misuse disorder (other than caffeine or tobacco or mild marijuana misuse) within the past six months; or a positive baseline urine drug screen.
2. A history of a current neurological disorder (including, but not limited to Parkinson's Disease, epilepsy, or Multiple Sclerosis)
3. History of head trauma resulting in unconsciousness
4. Contraindications for TMS, including any history of seizure other than febrile seizure, presence of ferromagnetic metal in cranium, presence of cochlear implant, presence of deep brain stimulation (DBS) electrodes based on medical history
5. Contraindications for MRI, including pacemakers or other metal in body
6. Suspected DSM-5 intellectual disability based upon clinical interview and psychosocial history
7. Pregnancy
8. Any change in type of antipsychotic medication in the last 30 days and dose in the last 14 days
9. Treatment with a benzodiazepine with a dose equivalent to lorazepam 2 mg/day or greater or any anticonvulsant due to the potential of these medications to affect TMS SICI score and the efficacy of rTMS
10. Prior history of treatment TMS (equivalent to 5 or more sessions of rTMS or theta-burst) in the past 6 months
11. Endorsement of active suicidal ideation on the Columbia-Suicide Severity Rating Scale (version: last 30 days) reflected by "yes" response on items 3, 4, or 5 of the ideation questions and/or "yes" to any of the four suicidal behavior items (actual attempt, interrupted attempt, aborted attempt, preparatory acts/behavior)
12. A score of 7 or more on the Simpson-Angus Scale of Extrapyramidal Symptoms (range 0-52 with higher scores indicating worse extrapyramidal symptoms)