A new drug based on ketamine could help treat depression

IT HAS BEEN over 30 years since a genuinely new type of drug for treating depression, or indeed any psychiatric illness, has come to market. Most antidepressants to date have been based on the "monoamine hypothesis", which holds that depression is caused by low levels of a class of chemical messengers (the monoamine neurotransmitters: serotonin, norepinephrine and dopamine) in the brain. Unfortunately, over a third of patients fail to respond to these drugs, and even when the drugs do work, it c...