(NaturalNews) The Veterans Administration (VA) is issuing a warning that the popular anti-smoking drug Chantix has been linked to an elevated risk of suicide. This warning comes months after the FDA first expressed concerns over the psychiatric effects of the drug.Chantix helps people quit smoking by simulating the effects of nicotine in the brain, while at the same time making real nicotine less effective. As early as November 2007, the FDA warned that many people were experiencing changes in emotions and behavior, including depression and suicidal thoughts, within weeks or even days of starting the drug. By February, the agency had strengthened its message, saying, "it appears increasingly likely that there may be an association between Chantix and serious neuropsychiatric symptoms."At least 40 cases of suicide and another 400 attempted suicides have been reported among those taking Chantix. In February, the FDA asked Chantix manufacturer Pfizer to make warnings about suicidal and other psychiatric side effects more prominent on the drug's label. But consumer advocacy groups have insisted that this measure does not go far enough. Public Citizen wants the FDA to put a stronger "black box" warning on the drug, while researchers from the Institute for Safe Medication Practices have expressed concern over non-psychiatric side effects such as loss of consciousness and seizures.When the FDA issued its first warning in November, the VA had already begun a study into the behavioral effects of Chantix on hundreds of Iraq war veterans suffering from post traumatic stress disorder. Participants in this ongoing study are being paid $30 per month.The VA did not pass the FDA's first warning on to study participants. When it finally warned them about potential psychiatric side effects after the second FDA announcement in February, the VA failed to mention the risk of suicide.The agency says that it will now send warning letters to all 940 study participants, plus an additional 31,000 veterans who have been prescribed the drug . The study will continue, but no new participants will be enrolled.Sources for this story include: www.newsinferno.com