Healthy Volunteers (n = 20)
Healthy Control Sample (n = 20): Healthy subjects (ages 18-55) will be selected who have not met criteria for any major psychiatric disorder, have no known first-degree relatives with mood disorders, and have a current score on the Hamilton Depression Rating Scale (HDRS; 17 item) (Williams 1988) in the not depressed range (less than or equal to 7). Control subjects will be matched to depressed subjects for age and gender.
MDD Samples (n = 30)
MDD Sample-Currently Depressed (n = 30): Patients (ages 18-55) will be selected with primary MDD currently depressed by DSM-IV criteria for recurrent MDD and current 17-item HDRS score greater than or equal to 18 or Montgomery-Asberg Depression Rating Scale (MADRS) (Noble et al 1991) greater than or equal to 20 indicating the moderately-to-severely depressed symptoms. All subjects must be physically healthy and aged 18 - 55 years.
EXCLUSION CRITERIA:
Subjects will be recruited who are drug-na ve or who have not received psychotropic drugs for at least 2 weeks (6 weeks for fluoxetine) prior to scanning. Effective medications will not be discontinued for the purposes of the study.
Subjects will also be excluded if they have:
a. serious suicidal ideation or behavior
b. psychosis
c. medical conditions or concomitant medications (see Appendix B) that are likely to influence PET measurement or have significant interactions with sertraline, citalopram or escitalopram.
d. a history of drug or alcohol abuse within 1 year or a lifetime history of alcohol or drug dependence (DSM-IV criteria)
e. positive urine drug screen
f. current pregnancy (as documented by pregnancy testing prior to scanning)
f. general MRI exclusion criteria
g. major depression that arose following another major medical or psychiatric condition, and h) prior participation in other research protocols within a year such that radiation exposure would exceed the annual guidelines
Additional exclusion criteria applied to patients who will have antidepressant treatment are:
a. previously proved unresponsive to a therapeutic trial of sertraline, citalopram or escitalopram.
b. previously developed allergic reactions to sertraline, citalopram or escitalopram, or discontinued each of these medications due to an adverse effect
Additional exclusion criteria applied to control subjects are:
a. subjects with a current or past history of other axis I psychiatric conditions
b. subjects with first-degree family members with current or past history of mood disorder.
Subjects beyond age 55 are excluded to reduce the biological heterogeneity encompassed by the MDD criteria, and to reduce the variability of PET data.