Over the years a number of theories of mood disorders have been proposed, including modulation of monoaminergic neurotransmission, alterations in neurotrophic factors, and the upregulation of adult hippocampal neurogenesis. However, these theories have not been sufficient to completely explain the pathology and treatment of mood disorders. Recently, neural plasticity theories of mood disorders have been widely developed, in part as an extension of these previous theories. Many studies show that depression, chronic stress, and other mood disorders may decrease neural plasticity, resulting in a reduced number of synaptic connections in brain structures known to be involved in depressive symptomology. This, in turn, can reduce chances of cell survival, particularly for new neurons, as well as decreased efficiency of neural connections. Conversely, antidepressant treatment increases neural plasticity and can increase cell survival. Thus, accumulating evidence demonstrates that neural plasticity may play an important role in mood disorders. This special issue will gather together recent findings that bridge the gap between previous theories and new theories that focus on neural plasticity.

For this reason, in this special issue, we invite investigators to contribute original research articles as well as review articles that will help us better understand the relationship between neural plasticity and mood disorders.

Potential topics include but are not limited to the following:

• Targeting dopamine transmission in depression
• Estrogen, stress, and anxiety in females
• Serotonin and neural plasticity in mood disorders
• Neural plasticity in depression
• Neural plasticity and drug addiction: connection to mood disorders
• The role of brain-gut peptide in mood disorders
• Sleep and plasticity in depression
• Neurotrophic factors, neuronal plasticity, and depression
• Electroconvulsive therapy-induced brain plasticity in mood disorders