Ketamine depression relief linked to brain-derived neurotrophic factor

An article from Nature linking ketamine's fast antidepressant action to BDNF and neural growth hit the media this week. One small dose of ketamine is enough to promote neurogenesis for an entire week. If you do any more than that side effects may include intermittent paranoid psychosis and catatonia.

A new study sheds light on why the anesthetic and "club drug" ketamine can relieve depression rapidly -- in hours, instead of weeks or months.

The new study found that just one dose of ketamine produced [an antidepressant] effect in a half an hour -- compared with the weeks or months this can take with standard antidepressants, in mice as well as in humans. Further, the new study found that the antidepressant effect of a single dose of ketamine lasted for a week.

The researchers, led by Lisa Monteggia, an associate professor of psychiatry at the University of Texas Southwestern Medical Center, also measured brain changes after animals underwent behavioral tests. Monteggia and her colleagues found that ketamine acted by increasing synthesis of BDNF, a nerve growth factor that supports the health of brain cells, helps them grow and can promote the development of new neurons.

Digging further, Monteggia's group found that ketamine increases BDNF by deactivating a chemical called eEF2 kinase (also known as CAMKIII), which normally suppresses BDNF production. Consequently, when eEF2 kinase is inactivated, brain cells produce more BDNF.

Which leads to the question, if a little BDNF is a good thing, is too much BDNF a bad thing?