Oxytocin Add-on for Stable Depressed Patients

Depression patients treated with even the best currently available antidepressant drugs continue to experience significant symptoms. There is a strong need for better treatments including treatments that can safely be given adjunctively with concurrent antidepressants in order to improve overall efficacy of treatment. Oxytocin is a neurohypophyseal peptide best known for its role as a neurohormone involved in parturition and lactation. In addition to these well established peripheral effects, there is a compelling body of converging evidence indicating that oxytocin plays a critical role in the regulation of a number of diverse centrally-mediated behavioral and cognitive processes that are highly relevant to mood regulation and mood disorders, including social attachment (Argiolas and Gessa 1990; McCarthy and Aaltemus 1997). Each subject will be enrolled for a 8 week treatment period after a screening phase. Study procedure involves weekly clinic visits as an outpatient. Twenty patients will be randomly assigned to either 40 IU oxytocin twice daily or vehicle placebo. After 4 weeks, treatments will be crossed over such that subjects that received oxytocin will receive placebo and vice versa. The study ratio is 1:1. Dose of oxytocin is based upon previous studies in humans showing improvement in psychiatric populations related changes in behavior and brain function (Kosfeld et al, 2005; Kirsch 2005; Heinrich M 2003). The total study duration for each individual subject will be approximately 9 weeks, which includes up to 31-day screening period, a baseline (randomization) visit, four week treatment period, 1 week washout, baseline 2 visit, and four weeks cross over treatment.