Effects of Antipsychotics on Brain Insulin Action in Females

Inclusion Criteria: * Age: 18-35 years * Body Mass Index (BMI) between 18.5 - 24.9 kg/m2 * Normal menstrual cycle (defined as cycle length ranging from 21 to 35 days over the past 6 months). Exclusion Criteria: * History of psychiatric illness (screened using the Mini International Neuropsychiatric Interview (MINI)); * Pre-diabetes or diabetes (fasting glucose ≥6.0 mmol/L, HbA1c\>6% or use of anti-diabetic drug); * Evidence of impaired insulin sensitivity, assessed using the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) ≥2.5; * Family history of diabetes in a first degree relative (parent or sibling) * Use of weight reducing agents; * History of kidney or liver disease; * Moderate-to-severe substance use; * Irregular menstrual cycles (e.g., menstruation occurs less than 21 days or more than 35 days apart, or not having menstruated for three months (or 90 days), or conditions such as endometriosis or polycystic ovary syndrome (PCOS) or prior surgical interventions such as a hysterectomy or oophorectomy); * Current use of hormonal birth control (e.g., pill, patch, hormonal intrauterine device \[IUD\], ring). Participants must have had at least 2 regular menstrual cycles following the discontinuation of hormonal birth control; * Pregnant, gave birth in the last year, or breastfeeding. Participants must have at least 3 regular menstrual cycles post-breastfeeding before beginning the study; * Current use of progesterone, estrogen, testosterone, or fertility treatment; * Major medical or surgical event within the last 6 months; * Any condition that interferes with safe acquisition of MRI data such as metal implants, pacemakers, cochlear implants, claustrophobia, etc. * Any contraindications to the investigational products as listed in the product monographs including known hypersensitivity to the drug or the excipients of the product (note: enzymatic lactose intolerance is NOT exclusionary) * Use of any of the prohibited medications listed in the product monograph of olanzapine (e.g., Levodopa and dopamine agonists and antihypertensive agents).