LOS ANGELES: A synthetic version of the active ingredient in marijuana, a legal treatment for nausea in cancer patients undergoing chemotherapy, also helps symptoms like pain, anxiety and depression, according to research presented on Friday.

"The findings show how great the potential is to improve the quality of life for cancer patients,"said lead investigator Dr Vincent Maida of the University of Toronto.

The 139-patient study involved a drug called nabilone, sold under the brand name Cesamet by Valeant Pharmaceuticals International.

It has been available in Canada for years, and was approved in May by the U.S. Food and Drug Administration for patients who have failed to respond adequately to conventional anti-nausea treatments.

The drug is part of a class known as cannabinoids that are similar to the active ingredient found in naturally occurring cannabis, or marijuana.

But Cesamet, as with similar drugs such as Solvay SA's Marinol, is designed to target specific cannabinoid receptors and does not carry the toxic effects associated with smoking marijuana, Maida said.