London, Oct 2 : Popular smoking cessation drug varenicline doesn’t increase the risk of self-harm or depression, according to a new study.

Researchers from the University of Bristol and the UK''s Medicines and Healthcare products Regulatory Agency (MHRA) compared the risk of self harm among people taking varenicline with the risk of self harm associated with other smoking cessation products bupropion and nicotine replacement therapy (patch, inhaler, gum, tablet or lozenge).

The participants were prescribed nicotine replacement products varenicline, or bupropion, reports British Medical Journal.

After controlling for confounding factors, the researchers found no clear evidence of an increased risk of self-harm, suicidal thoughts or depression associated with either varenicline or bupropion.

Although the researchers found no strong evidence of an increased risk of self harm linked to varenicline, "the limited power of the study means we cannot rule out either a halving or a twofold increased risk."

They call for more investigation of varenicline''s effect on suicide risk in other databases and secondary analysis of all adverse event reporting in clinical trials. (ANI)