The goal of this clinical trial is to learn about cognition in psychotic disorders (schizophrenia, bipolar disorder, and schizoaffective disorder). The main question it aims to answer is: Can we use magnetic stimulation to change processing speed (how quickly people can solve challenging tasks).

Participants will be asked to perform cognitive tasks (problem-solving) and undergo brain scans before and after transcranial magnetic stimulation (TMS). TMS is a way to non-invasively change brain activity. Forms of TMS are FDA-approved to treat depression and obsessive compulsive disorder. In this study, we will use a different form of TMS to temporarily change brain activity to observe how that changes speed in problem-solving.

Psychotic disorders including schizophrenia, bipolar disorder, and related illnesses are severe, debilitating, and often fatal. Cognitive impairments in psychosis are among the leading predictors of disability and poor quality of life; despite this, there are no first-line interventions to target these symptoms.

This trial will test the hypothesis that cognitive performance in these disorders is modifiable and specifically that it can be modified non-invasively. Transcranial magnetic stimulation (TMS) is a neuromodulation technique that utilizes magnets to alter brain activity non-invasively. TMS has received FDA approval as a therapeutic intervention for multiple psychiatric disorders. In this study, we will use different forms of TMS to modulate a specific brain circuit and we will measure the outcomes of this circuit manipulation. These outcomes include performance on cognitive tests and also changes to the circuit itself that we can measure using magnetic resonance imaging (MRI).

Inclusion Criteria:

• Age between 18-55 years
• Diagnosis of a psychotic disorder (i.e. schizophrenia or schizoaffective disorder or bipolar disorder type I)
• Must be able to read, speak and understand English
• Must be judged by study staff to be capable of completing the study procedures
• Participants will be in stable outpatient treatment with no recent (within the past 30 days) hospitalizations or changes in their medication regimens.

Exclusion Criteria:

• Diagnostic and Statistical Manual 5 diagnosis of moderate substance use disorder within the past month

• Conditions that might result in increased risks of side effects or complications from rTMS or MRI, including:

  • Intracranial pathology from a known genetic disorder (e.g., Neurofibromatosis 1, tuberous sclerosis) or from acquired neurologic disease (e.g. stroke, tumor), cerebral palsy, history of severe head injury, or significant dysmorphology;
  • History of fainting spells of unknown or undetermined etiology that might constitute seizures
  • History of multiple seizures or diagnosis of epilepsy
  • Any progressive (e.g., neurodegenerative) neurological disorder such as multiple sclerosis or Parkinson's disease
  • Chronic (particularly) uncontrolled medical conditions that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.)
  • Metal implants (excluding dental fillings) unless cleared by the responsible covering MD (i.e. MRI compatible joint replacement)
  • Pacemaker
  • Implanted medication pump
  • Vagal nerve stimulator
  • Deep brain stimulator or transcutaneous electric nerve stimulation unit
  • Ventriculo-peritoneal shunt
  • Signs of increased intracranial pressure
  • Intracranial lesion
  • History of head injury resulting in prolonged loss of consciousness (>15minutes) or neurological sequelae
  • Pregnancy: All participants capable of becoming pregnant will be required to have a pregnancy test; any participant who is pregnant will not be enrolled in the study.

The study design is a crossover design i.e. all participants will receive all three rTMS interventions (iTBS, cTBS, sham rTMS). The participant will be blinded to which intervention is happening on a given study visit. The order of these visits will be determined randomly for each participant.