Researchers from Concordia University in Canada and colleagues found that those who struggle with mental illness simply have a tougher time quitting smoking, no matter how much they want to.
People diagnosed with depression need to step out for a cigarette twice as often as smokers who are not dealing with a mood disorder, researchers found.
The findings showed that those who struggle with mental illness have a tougher time quitting.
The anxiety, cravings or lack of sleep that accompany typical attempts to quit cold turkey will have them scrambling for the smokes they might have sworn off earlier that evening, researchers said.
A person without clinical depression is better equipped to ride things out, they said.
The study found that a bit more exercise can reduce the compulsion to reach for a cigarette - even if it is not enough to alleviate the symptoms of the depression itself.
In an 18-month study, quitting was found to be easier in the midst of even the most basic workouts, since withdrawal symptoms were reduced in the aftermath of regular walks.
"Our hope is that this study will continue to sensitise researchers and clinicians on the promising role of exercise in the treatment of both depression and smoking cessation," said first author Paquito Bernard of the University of Montpellier in France.
The study was published in the journal Nicotine & Tobacco Research.