Most anti-depressants take weeks or sometimes months to take effect, which can be difficult for those suffering from severe depression or anxiety. Researchers from Yale University have now found that the drug ketamine can take effect within hours. The drug has already been very effective in treating severely depressed patients, and researchers hope this finding will lead to the development of a safer, easier-to-use form of the drug.
The researchers found that ketamine quickly improved depression symptoms and behaviors and restored connections between brain cells that were damaged by chronic stress in rats. Senior author of the study Ronald Duman, professor of psychiatry and pharmacology at Yale, said it’s like a “magic drug,” and that one dose can last for seven to ten days.
Ketamine is tradionally used as a general anesthetic for children, but ten years ago, researchers from the Connecticut Mental Health Center discovered that it worked as an anti-depressant in lower doses. In these studies, almost 70 percent of patients who were resistant to other anti-depressant treatments improved within hours after being given ketamine. These studies were successfully replicated at the National Institute of Mental Health. Because the drug must be delivered intravenously under medical supervision and because it can be abused recreationally, its clinical use has been limited.
Duman and his colleagues wanted to see if they could track the molecular action of the drug in the brains of rats in order to find potential targets for a safer, easier-to-use form of the drug. They found that ketamine affects a pathway that quickly forms new synaptic connections between neurons, or synaptogensis. Co-author George Aghajanian said that understanding the underlying effects and mechanisms of ketamine will allow researchers to target a variety of sites within the pathway.
The researchers discovered that the enzyme mTOR, which controls the protein synthesis required for creating new synaptic connections, is a critical point in the pathway. Targeting this enzyme could help sustain the initial rapid effect of ketamine.
The authors noted that ketamine has also been tested as a way to quickly treat people with suicidal thoughts.
Source: Science Daily, Secrets of ‘Magic’ Antidepressant Revealed, August 20, 2010