Eligibility Criteria:
Inclusion Criteria:
* DSM-5 diagnosis of schizophrenia, schizoaffective disorder, schizophreniform disorder, and other specified or unspecified schizophrenia spectrum and other psychotic disorder.
* Experienced a first psychotic episode within the last 5 years.
* Self-reported cannabis use at least twice/week for at least the last 4 weeks.
* THCCOOH serum levels of ≥ 5 ng/mL.
* Total score ≥45 on the 18-item version of the Brief Psychiatric Rating Scale.
* Able to give written informed consent.
* Normal or corrected to normal vision.
* If medicated, no change in psychiatric medication within the preceding 4 weeks, with no foreseeable changes.
Exclusion Criteria:
* DSM-5 diagnosis of Substance Use Disorder other that cannabis or nicotine within the last year (recreational use is not exclusionary).
* Currently undergoing active treatment for Cannabis Use Disorder other than low-level (once/week or less) psychosocial intervention.
* Uncontrolled hypertension (resting systolic BP above 150 or diastolic above 95 mm Hg).
* Cardiovascular disease, such as history of myocardial infarction and ischemia, heart failure, angina, severe arrhythmias, or EKG abnormalities (Wolf-Parkinson-White syndrome, Complete left bundle branch block, PR interval \<120 ms or \>200 ms, Prolonged QT interval (corrected) \>500 ms, Cardiac arrhythmias as defined by PACs \>3 per min or PVCs \>1 per min).
* History of or current neurological illness, such as stroke, seizure disorders, neurodegenerative diseases, or organic brain syndrome.
* Intellectual disability.
* Pregnant or lactating.
* Diabetes.
* Significant kidney or liver impairment.
* Any chronic or severe infectious disease, including HIV and hepatitis.
* Cancer.
* Use of any barbiturates, diazepam, diltiazem, verapamil, protease inhibitors, any anticonvulsant medications (including valproate/valproic acid, lamotrigine, carbamazepine, and clobazam), glipizide, glyburide, warfarin, and cyclophosphamide/ ifosfamide, due to potential interaction with CBD at the metabolic level.
* Suicidal ideation currently or within last 6 months (score of \>/= 3 on the Columbia Suicide Severity Rating Scale).
* Less than the lower limit of normal hemoglobin and hematocrit at screening.
* Elevated transaminase levels \>3 times the ULN, accompanied by elevations in bilirubin \>2 times the ULN.