Many chronically depressed and treatment-resistant patients experience immediate relief from symptoms after taking small amounts of the drug ketamine. For a decade, scientists have been trying to explain the observation first made at Yale University.
Today, current evidence suggests that the paediatric anaesthetic helps regenerate synaptic connections between brain cells damaged by stress and depression, according to a review of scientific research written by Yale School of Medicine researchers and published in the 5 October issue of the journal Science.
Ketamine works on an entirely different type of neurotransmitter system than current antidepressants, which can take months to improve symptoms of depression and do not work at all for one out of every three patients.
Understanding how ketamine works in the brain could lead to the development of an entirely new class of antidepressants, offering relief for tens of millions of people suffering from chronic depression.
''The rapid therapeutic response of ketamine in treatment-resistant patients is the biggest breakthrough in depression research in a half century,'' said Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and Professor of Neurobiology.
Duman and George K Aghajanian, also professor of psychiatry at Yale, are co-authors of the review.