NMDA Modulation in Major Depressive Disorder

Major depressive disorder (MDD) is a complex and multi-factorial disorder. Most of the current antidepressants are based upon the monoamine hypothesis which cannot fully explain the etiology of depression. Many patients have significant side effects after treatment with antidepressants which hamper the motivation for treatment and medication adherence. NMDA hypofunction has been implicated in the pathophysiology of depression. MDD is often associated with cognitive deficits which are not necessarily recovered by current antidepressants. The NMDA receptor regulates synaptic plasticity, memory, and cognition. In our previous studies, cognitive improvement has been observed with treatment of NMDA enhancers. Therefore, this study will examine the efficacy and safety as well as cognitive function improvement of NMDAE in the treatment of MDD in the general adults by comparing with sertraline (a selective serotonin reuptake inhibitor \[SSRI\]) and placebo. The investigators will enroll non-elderly adult patients with MDD for an 8-week treatment. All patients will be randomly assigned into three groups: NMDAE, sertraline, or placebo. The investigators will biweekly measure clinical performances and side effects. Cognitive functions will be assessed at baseline and at endpoint of treatment by a battery of tests. The efficacy of three groups will be compared.