Inclusion Criteria for Psychosis Participants:
- Age between 18-65 years
- Diagnosis of a psychotic disorder according to DSM-5 criteria and confirmed by SCID
- Current cannabis use of at least 2/10 on a Visual Analog Scale
- Current cannabis use (confirmed by urine cannabis testing)
- 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 psychiatric treatment and psychiatrically stable with no recent (within the past 30 days) psychiatric hospitalizations or changes in their psychiatric medication regimens.
Inclusion Criteria for Healthy Controls:
\- All of the above except for participants will not have a diagnosis of a psychotic disorder nor a first-degree relative with a psychotic disorder.
Exclusion Criteria for ALL participants:
- DSM-5 intellectual disability
- Substance use disorder (other than cannabis or nicotine) within the past three months
- Positive urine drug screen for illicit substance use that can increase seizure risk (cocaine, benzodiazepines, amphetamine, methamphetamine)
- Any history of a progressive or genetic neurologic disorder (e.g. Parkinson's disease, multiple sclerosis, tuberous sclerosis, Alzheimer's Disease) or acquired neurological disease (e.g. stroke, traumatic brain injury, tumor), including intracranial lesions
- History of head trauma resulting in any loss of consciousness (>15 minutes) or neurological sequelae
- Current history of poorly controlled headaches including chronic medication for migraine prevention
- History of fainting spells of unknown or undetermined etiology that might constitute seizures
- History of seizures, diagnosis of epilepsy, or immediate (1st degree relative) family history epilepsy with the exception of a single seizure of benign etiology (e.g. febrile seizures) in the judgment of a board-certified neurologist
- Chronic (particularly) uncontrolled medical conditions that may cause a medical emergency in case of a provoked seizure (cardiac malformation, cardiac dysrhythmia, asthma, etc.)
- Any metal in the brain or skull (excluding dental fillings) or elsewhere in the body unless cleared by the responsible covering MD (e.g. MRI compatible joint replacement)
- Any devices such as pacemaker, medication pump, nerve stimulator, TENS unit, ventriculo-peritoneal shunt unless cleared by the responsible covering MD
- All female participants of child-bearing age will be required to have a pregnancy test; any participant who is pregnant or planning to become pregnant will not be enrolled in the study
- Medications will be reviewed by the responsible covering physician and a decision about inclusion will be made based on the participant's past medical history, drug dose, history of recent medication changes or duration of treatment, and use of CNS active drugs. The published TMS guidelines review of medications to be considered with rTMS will be taken into consideration given their described effects on cortical excitability measures.
- Any changes in medications or hospitalizations within the past 30 days.
- Participants who, in the investigator's opinion, might not be suitable for the study or would be unable to tolerate the study visit
These exclusion criteria strictly follow all recommended guidelines as endorsed by the International Federation of Clinical Neurophysiology and the International Society for Transcranial Stimulation.