This observational, case-control study will enroll 150 participants, of which 100 will be smokers with schizophrenic-related disorders and 50 will be smokers without a mental illness. Upon completing baseline assessments, participants will smoke a single cigarette. Approximately two minutes following, 3 to 4 ounces of blood will be analyzed for nicotine and cotinine levels. An expired carbon monoxide reading will also be measured. This measurement correlates with the amount of smoke inhalation. Individual participant studies will be completed in 1 to 2 hour-long sessions.