Patient description: The patient is a 35-year-old woman with myasthenia gravis, class IIa. She complains of diplopia and fatigue and weakness that affects mainly her upper limbs. She had a positive anti-AChR antibody test, and her single fiber electromyography (SFEMG) was positive. She takes pyridostigmine 60 mg three times a day. But she still has some symptoms that interfere with her job. She is a research coordinator and has 3 children. Her 70-year-old father has hypertension. She does not smoke or use illicit drugs. She drinks alcohol occasionally at social events. Her physical exam and lab studies were not remarkable for any other abnormalities. BP: 110/75 Hgb: 11 g/dl WBC: 8000 /mm3 Plt: 300000 /ml Creatinine: 0.5 mg/dl BUN: 10 mg/dl Beta hcg: negative for pregnancy

Clinical trial eligibility criteria: eligible ages (years): 18.0-65.0,  Schizophrenia Impulsive Behavior for schizophrenia subjects: 1. Men and women age 18 2. Communicative in English. 3. Provide voluntary, written informed consent. 4. Physically healthy by medical history,and ECG examination. 5. BMI > 17.5 and < 45. 6. Diagnosis of schizophrenia (ICD-10 F20) or schizoaffective disorder (ICD-10 F25) confirmed by Structured Clinical Interview for Diagnostic and Statistical Manual (DSM)-V (SCID) or diagnostic interview with a trained clinician. 7. Stable medication regimen over at least the past two weeks, including the use of either an oral or intramuscular administration of an antipsychotic medication. Additionally, subjects may take any prescribed medication aside from a nicotine-containing product as long as it has been regularly taken over the past two weeks, including as-needed ("PRN") medication. 8. Negative urine toxicology and negative urine cotinine (to confirm no recent nicotine use) at screening. 9. Does not meet for substance or alcohol use disorder per the SCID over the past 6 months 10. For females, no longer of child-bearing potential, or agreeing to practice effective contraception during the study (e.g., established use of oral, injected or implanted hormonal methods of contraception; placement of an intrauterine device [IUD] or intrauterine system [IUS]; barrier methods: condom with spermicidal foam/gel/film/cream/suppository or occlusive cap [diaphragm or cervical/vault caps] with spermicidal foam/gel/film/cream/suppository; male partner sterilization; or true abstinence when this is in line with the preferred and usual lifestyle of the subject); and, 11. For females of child-bearing potential, must have negative urine pregnancy test at time of screening visit and before each testing day. 12. Not breastfeeding/nursing at time of screening or at any time during the study  for schizophrenia subjects: 1. Age less than 18 or greater than 65. 2. Not communicative in English. 3. Unable to provide written informed consent. 4. Active suicidal ideation or suicidal behavior. 5. Current, unstable medical or neurological illness or significant abnormality on ECG. 6. History of severe head trauma. 7. BMI < 17.5 or > 45. 8. History of allergy to transdermal patches. 9. Screening visit resting heart rate > 110 or < 50 beats per minute, or known history of clinically significant cardiac rhythm abnormalities. 10. Screening visit systolic blood pressure > 160 or < 90, or diastolic blood pressure > 95 or < 50. 11. Positive urine toxicology or positive urine cotinine during screening. 12. Meets for diagnosis of substance or alcohol use disorder by SCID within the past 6 months. 13. Reports any tobacco smoking or nicotine use over the past month. 14. Not taking an antipsychotic medication. 15. Positive urine pregnancy test at time of screening, before each testing day, or any potential concern for pregnancy at any time during the study 16. Breastfeeding/nursing at time of screening or at any time during the study. for healthy volunteer subjects: All of the above except for subjects will be psychiatrically healthy and not taking psychotropic or potentially psychoactive prescription medication for healthy volunteer subjects: All of the above and in addition: 1. Current use of psychotropic or potentially psychoactive prescription medication. 2. Major psychiatric disorder as determined by DSM-5 (schizophrenia, major depression, bipolar disorder, obsessive-compulsive disorder, post-traumatic stress disorder, etc.)