Impact of GABA-Enhancing Agents on Cortical GABA Concentrations Across the Menstrual Cycle in Women

Inclusion Criteria:

- Women ages 18-45 and able to give voluntary written informed consent;

- Regular menstrual periods of 24-35 days in length;

- Body mass index 18.5 to 30 kg/m2;

- No past or present DSM-IV psychiatric or substance dependence diagnosis by structured
diagnostic interview (SCID-NP); no substance abuse history within the previous 2
years;

- Absence of mood symptoms across the menstrual cycle during one month of prospective
daily ratings with the Daily Record of Severity of Problems (DRSP); the DRSP is based
on the DSM-IV research criteria for premenstrual dysphoric disorder (PMDD) and has
been used in numerous studies to confirm the presence or absence of significant
premenstrual mood and behavioral difficulties;

- Must be willing and able to participate in at least three of the four challenge
paradigms.

Exclusion Criteria:

- Medical, neurologic or cerebrovascular disorder (CVA, seizure disorder, etc.);

- Family history of first degree relative with an Axis I psychiatric or substance
dependence disorder (excepting alcohol and nicotine) (per subject report);

- Current treatment with psychoactive medication;

- Diabetes controlled by means other than diet;

- Use of steroid contraceptives (any method involving hormones) within the previous 4
months;

- Habitual consumption of more than 7 alcoholic drinks per week or more than 2 drinks
on any particular occasion; must be willing to abstain from alcohol consumption for
48 hours prior to each 1H-MRS scan;

- Implanted metallic devices.