Scientific American, March 2012 -- "Lifting the Black Cloud," Robin Marantz Henig
The current class of antidepressant medications, which focus on serotonin and norepinephrine, have limited effectiveness and come with a range of negative side effects. As a result, people suffering from depression often find themselves bouncing from medication to medication, with more or less effectiveness. Henig descibes several novel drug targets that are under investigation, and which promise a future of more choice, and better results for the depressed.
Ketamine is one such substance, which shows promise in speeding neural regeneration in the prefrontal cortex, reducing or reversing the neural atrophy there that often is associated with depression. Acetylcholine is another neurotransmitter that shows promise as a target; ironically, it was one of the first systems targeted for study, but was largely ignored after serotonin showed so much promise. Other drugs target nicotinic repceptors, and seem to be effective at stimulating neural growth in the hippocampus. Finally, another novel research angle is to focus on inflammation, which is often associated with depression.