Evoked Responses as Pharmacodynamic Biomarkers in Healthy and Schizophrenic Participants (MK-4334-007)

Inclusion Criteria: HC Participants: * Is in generally good health * Has no history of clinically relevant neuropsychiatric illness * Is a mild-to-moderate tobacco user of ≥1-year duration, smoking the equivalent of \~10-15 cigarettes/day Participants with Mild-to-Moderate SZ: * Has a current diagnosis of SZ with a duration ≥1 year * Is clinically stable and in the residual (non-acute) phase of illness for ≥12 weeks prior to the study * Is stably maintained on a regimen of up to 2 first- or second-generation antipsychotics with no dose changes \>50% in combination with concomitant medication commonly prescribed to this population for ≥8 weeks prior to screening and during the study * Is a mild-to-moderate tobacco user of ≥1-year duration, smoking the equivalent of \~10-15 cigarettes/day All Participants: * For males, agrees to be abstinent from heterosexual intercourse, or use an approved contraception method, during the study and for 90 days after the last dose of study drug * For females, is not of childbearing potential * Is willing to comply with restrictions on the use of nicotine or nicotine-containing products during the study Exclusion Criteria: HC Participants: * Has known biological family history of psychotic disorder in a first or second degree relative Participants with Mild-to-Moderate SZ: * May be excluded from participation by the investigator based on treatment history and/or performance on various screening tests All Participants: * Is positive for hepatitis B surface antigen, hepatitis C antibodies, or human immunodeficiency virus (HIV) * Is at imminent risk of self-harm * Has had major surgery or donated blood within 4 weeks prior to screening * Has evidence of cognitive impairment or significant mental disability * Has a history of clinically significant abnormality or disease * Has a history of cancer (malignancy) * Is unable to refrain, or anticipates use, of any non-prescription drugs or herbal remedies * Has participated in another clinical study within 6 weeks or 5 half-lives (whichever is greater) prior to screening