Acetylcholine, Tobacco Smoking, Genes and Nicotinic Receptors

Inclusion Criteria: * who are able to read and write * who are able to give voluntary written informed consent * have no current uncontrolled medical condition such as neurological, cardiovascular, endocrine, renal, liver, or thyroid pathology * have no history of a neurological or psychiatric disorder (DSMIV Axis 1 and 2) other than schizophrenia in schizophrenia subgroup * have not regularly used any prescription, herbal or illegal psychotropic medications (e.g. antidepressants, antipsychotics, anxiolytics, ecstasy) in the past 6 months (controls). * Subjects with schizophrenia have not used any herbal or illegal substances in the past 6 months (medication inclusion listed below in Aim 5) * drink less than \<21 drinks/week for women and less than \<35 drinks per week for men * have not used marijuana in the past 30 days and have not met criteria for dependence in the past 2 years * If female, not pregnant or breast feeding * If female of childbearing age, must use an acceptable method of birth control, as determined by the principal investigator * do not suffer from claustrophobia or any MR contradictions * willing to donate blood for genetic studies * willing to be followed up monthly after study participation via phone or email contact Exclusion Criteria: * Presence of acute or unstable medical or neurological illness. Subjects will be excluded from the study if they present with any history of serious medical or neurological illness or if they show signs of a major me…