Functional MRI of Stress in Obesity

Inclusion Criteria: 1. Between ages 18-50 years old. 2. Able to read and write. 3. negative urine toxicology screens during intake appointments indicating no history of current or past dependence on alcohol or illicit drug use. 4. WOMEN: have a regular menstrual cycle. 5. BMI: 30 \< BMI \< 35 for obese subjects (upper limit of 35 selected given our experience with heavier individuals fitting comfortably in the fMRI scanner) and 18.5 \< BMI \<25 for normal weight subjects (Institute, 2006) Exclusion Criteria: 1. any major neurological illness or injury and any current or prior clinically significant mental health (including PTSD) or substance use disorder (with exception of nicotine dependence) as determined by SCID interview; 2. Regular use of any psychoactive drugs including anxiolytics and antidepressants. 3. Any significant current medical condition such as neurological, cardiovascular, endocrine, renal, liver, thyroid pathology; subjects on medications for any medical condition will be excluded. 4. Any subjects with foreign ferromagnetic metal objects in their body or other MR contraindications will be excluded including subjects who work as welders. 5. Women on oral contraceptives, peri- and post-menopausal women, and pregnant or lactating women (as alterations in stress response are associated with these states).