Neuromodulation of Social Cognitive Circuitry in People With Schizophrenia Spectrum Disorders

This study is a randomized, double blind, sham controlled study which aims to use repetitive transcranial magnetic stimulation (rTMS), a form of neuromodulation, to target the neural circuitry of social cognitive (SCog) impairments in people with Schizophrenia Spectrum Disorders. We will randomize 60 people with SSDs to three groups: 20 to a conventional form of rTMS (i.e. 10 Hz rTMS); 20 to intermittent theta burst stimulation (iTBS); and 20 to either sham 10Hz rTMS stimulation or sham iTBS. We will determine whether these treatments can change the functional connectivity of key SCog brain circuits by targeting a brain region known as the dorsomedial prefrontal cortex (DMPFC). Since each person's anatomical and functional brain profile is slightly different, we will optimize the orientation and location of coil placement in each individual. Overall, our proposal follows a target engagement framework, including specifics regarding testing brain stimulation parameters (i.e., rTMS vs. iTBS) and individualizing coil placement for optimal targeting. We anticipate that active 10 Hz rTMS or iTBS will demonstrate target engagement compared to sham, and potentially ameliorate SCog deficits in people with SSDs. Our primary goal is to identify which treatment best induces change in SCog brain circuitry and secondarily which treatment is best tolerated and induces changes in social cognitive performance.

Inclusion criteria

• Age 18-55 years;
• Male or Female;
• DSM-5 diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder; other specified psychotic disorder (documented by SCID-5);
• Prescription of antipsychotic medication for at least 60 days and constant dose for 30 days prior to study entry (either first or second generation antipsychotics permitted);
• Able to participate in the informed consent process and provide voluntary informed consent.

Exclusion criteria

• DSM-5 substance use disorder (other than caffeine, mild cannabis use, or tobacco) within the past six months; or a positive baseline urine drug screen (except cannabis for mild use). Only participants meeting a moderate to severe cannabis use disorder will be excluded
• Type 1 diabetes mellitus (i.e., insulin-dependent diabetes mellitus with onset < 35 years of age and/or diabetes mellitus that has been complicated by a prior documented episode of ketoacidosis)
• Acute or unstable medical illness (e.g. delirium, cancer, uncontrolled diabetes, decompensated cardiac, hepatic, renal or pulmonary disease, stroke, or myocardial infarction), whose pathology or treatment could alter the presentation or treatment of schizophrenia or significantly increase the risk associated with the proposed treatment protocol
• Neurological disease associated with extrapyramidal signs and symptoms (e.g. Parkinson's disease); epilepsy (i.e. seizures not due to medication/drugs or due to fever) or physical signs of stroke; any diagnosis of a Central Nervous System (CNS) disorder
• Requires a benzodiazepine with a regular dose equivalent to lorazepam 2 mg/day or higher or any anticonvulsant due to the potential of these medications to limit the efficacy of rTMS
• Suspected DSM-5 intellectual disability based upon clinical interview and psychosocial history or estimated IQ of <71
• Prior Psychosurgery
• Presence of MRI contraindications (e.g. pacemakers)
• Pregnancy (self-report)
• rTMS treatment in the last 5 years
• Non-English speakers