• Depression illness severity based on Beck Depression Inventory (BDI) and Edinburgh Postnatal Depression Scale (EPDS) [ Time Frame: Measured at baseline; Weeks 4, 8, and 12 of treatment; and Months 3 and 6 of follow-up ] [ Designated as safety issue: No ]
• General illness severity based on Clinical Global Impression (CGI) scale [ Time Frame: Measured at baseline; Weeks 4, 8, and 12 of treatment; and Months 3 and 6 of follow-up ] [ Designated as safety issue: No ]
• Social functioning based on Postpartum Adjustment Questionnaire (PPAQ) [ Time Frame: Measured at baseline; Weeks 4, 8, and 12 of treatment; and Months 3 and 6 of follow-up ] [ Designated as safety issue: No ]
• Anxiety based on Beck Anxiety Inventory (BAI) [ Time Frame: Measured at baseline; Weeks 4, 8, and 12 of treatment; and Months 3 and 6 of follow-up ] [ Designated as safety issue: No ]

This study will evaluate the effectiveness of antidepressant medication alone and interpersonal psychotherapy alone in treating women with postpartum depression.

Postpartum depression (PPD) occurs in approximately 13% of postpartum women. The impact of PPD is significant, including emotional distress for the woman as well as disturbances in infant development. Common signs of depression after childbirth may include anxiety, irritability, low energy, and lack of concern for self or infant. If left untreated, PPD may last for more than 1 year, causing strain on family life and the mother's relationship with her infant. Infants of depressed mothers are also at a higher risk for developmental delays, behavioral problems, and difficulty eating and sleeping. Despite the public health significance of PPD, relatively little research has been done to determine the most effective treatments. Specifically, there is a lack of research concerning the use of antidepressant medication for treating PPD. Interpersonal psychotherapy (IPT), which focuses on interpersonal issues related to depression, has been more thoroughly studied for the treatment for PPD, but it has not been compared to the other treatment. This study will evaluate the effectiveness of antidepressant medication alone and IPT alone in treating women with PPD.

Participation in this double-blind study will last 9 months. Participants will first undergo initial assessments, which include interviews about depressive symptoms, self-report forms about medical history, blood tests, and a pregnancy test. Participants will then be randomly assigned to one of three treatments: sertraline, placebo, or IPT. All three treatments will be administered over 12 weeks. Participants assigned to take sertraline or placebo will attend eight 30-minute sessions over the 12-week treatment period. During these sessions, participants will be administered the study medication and will be assisted with parenting issues and skills by a psychiatrist. Participants receiving IPT will attend weekly 45-minute sessions over the 12-week treatment period. These sessions will focus on improving relationships with others, setting goals, and increasing coping skills. All participants will also complete interviews and questionnaires about their depression once a month. Following the 12 weeks of treatment, participants will undergo follow-up visits occurring at Weeks 1 or 2 and Months 3 and 6 post-treatment. Follow-up assessments will repeat initial interviews and questionnaires and will include a form about the infant's nature.

• Drug: Sertraline
• Drug: Placebo
• Behavioral: Interpersonal psychotherapy (IPT)
• Behavioral: Clinical management

• Placebo Comparator: Participants taking placebo pill plus clinical management
• Active Comparator: Participants receiving medication treatment alone with sertraline plus clinical management
• Active Comparator: Participants receiving interpersonal psychotherapy (IPT) alone

Inclusion Criteria:

• Primary DSM-IV diagnosis of major depressive disorder by clinical interview
• Score of greater than 15 on HAM-D
• Delivery of an infant within the 6 months prior to study entry
• Able to speak and read English sufficiently to complete the study procedures
• Willing to use effective birth control methods throughout the study

Exclusion Criteria:

• Woman whose infant has died prior to study entry
• Breastfeeding
• Current or past diagnosis of bipolar disorder, schizophrenia or other psychotic disorder;
• Diagnosis of alcohol or drug abuse or dependence (except nicotine) or anorexia in the past year;
• Psychotic symptoms;
• Acute suicidal or homicidal risks;
• Women who have been on an antidepressant for more than 14 days prior to consent, (if less than 14 days and willing to taper off, will be eligible to continue once tapered off);
• Women on daily anxiolytic medication (i.e. benzodiazepine, buspirone) or daily psychoactive herbal preparation (St. John's Wort or Fish Oil) (if willing to discontinue these substances may be eligible once they have been tapered off);
• Medications taken PRN over the listed dose and frequency (women will still be eligible if they take: Lunesta/Eszopiclone 3 mg or less, up to 3 nights a week, Ambien/Zolpidem 5mg or less, Ambien CR 6.25 mg or less, up to 3 nights a week, Lorazepam or equivalent benzodiazepine dose: 0.5 mg up to 3 nights a week, Sonata/Zaleplon: 5 mg or less, up to 3 nights a week, Rozerem/Ramelteon: 8 mg or less, up to 3 nights a week);
• If they take antidepressants PRN for insomnia (eg: Desyrel/Trazodone, Elavil/Amitriptyline, Remeron/Mirtazapine;
• Ongoing concurrent psychotherapeutic treatment or psychotherapeutic treatment within the last month;
• Psychiatric symptoms requiring specialized psychiatric treatment;
• Significant medical disorder that would make sertraline treatment contra-indicated,
• Previous trial of IPT therapy with a certified IPT therapist or an adequate trial of sertraline (i.e. at least 8 weeks of at least 100 mg daily of sertraline).