This study will be conducted at two international treatment sites, including the University of Pittsburgh and the University of Pisa, Italy. Participants will be randomly assigned to receive either interpersonal psychotherapy (IPT) or escitalopram pharmacotherapy for a minimum of 32 weeks or approximately 8 months. Participants whose symptoms become stabilized will continue the initial treatment for another 6 months; those who do not will have the second treatment added to their regimen until remission occurs. Clinical evaluations and questionnaires will be used to assess participants.