Inclusion Criteria:  meeting Criteria of Psychosis-Risk Syndromes (COPS) criteria on the Structured Interview for Psychosis-Risk Syndromes (SIPS) capacity to provide informed consent if female, participant is not of child-bearing potential, defined as females who have undergone a sterilization procedure or have been post-menopausal for at least 1 year prior to screening OR participant is of child-bearing potential and agrees to use a medically approved method of birth control for the duration of the study  Exclusion Criteria:  meeting criteria for any other DSM-5 diagnosis at the time of the study (except -personality disorder, nicotine use disorder, or other substance use disorder in full remission) concomitant or past neurological condition visual impairment which is not corrected to normal by prescription glasses history of reading disability past antipsychotic treatment at a therapeutic dose current treatment with a psychotropic medication pregnancy (as identified on self-report and/or rapid urine pregnancy test) or intent to become pregnant according to self-report breastfeeding or plan to do so history of kidney stones current treatment with an antibiotic current treatment with nitroglycerin allergy to any ingredients in either the investigational product or placebo product