A newer smoking cessation drug is not linked to an increased risk of self-harm or depression, a British study suggests. Health Canada and the U.S. Food and Drug Administration have warned that people taking varenicline  sold in Canada as Champix and in the U.S. as Chantix — have experienced unusual feelings of agitation, depressed mood, hostility, changes in behaviour or impulsive or disturbing thoughts, such as ideas of self-harm or of harming others.

The smoking cessation product is effective. British researchers writing in Friday's issue of the British Medical Journal looked for more evidence of adverse neuropsychiatric effects related to the drug. The team analyzed information on 80,660 men and women, aged 18 to 95, who were prescribed a smoking cessation product between September 2006 and May 2008.