Dysfunctional hippocampal activity affects emotion and cognition in mood disorders

Mood disorders, such as major depressive disorder (MDD), bipolar disorder and generalized anxiety disorder usually comprise mood related as well as cognitive symptoms and the interaction between these symptoms is still not clear. Most antidepressant drugs have a positive effect on mood but do not treat the cognitive dysfunctions or even aggravate the symptoms. In this review we will evaluate the association between mood and cognition in the context of mood disorders. In the first section we will summarize the brain circuits at the intersection between cognition and emotion, highlighting the role of the hippocampus. In the second section, we will survey the contribution of the glutamate and GABA systems in the pathophysiology of mood disorders, making an effort to understand the link between emotions and cognition and how novel therapeutic approaches deal with them. In the third section we will explore the monoamine involvement in the emotion/cognition duality in the context of mood disorders. Finally we will underline the role of synaptic plasticity and neurogenesis in depression. We consider that a broader knowledge about the integrative mechanisms involved in specific aspects of mood disorders is crucial in the development of more powerful and effective antidepressant drugs. This article is part of a Special Issue entitled: Brain Integration.