The authors explained that the widely held belief that giving up smoking makes you more edgy and that smoking relieves stress has been challenged by their findings.
The researchers wrote:
"The belief that smoking is stress relieving is pervasive, but almost certainly wrong. The reverse is true: smoking is probably anxiogenic (causes anxiety) and smokers deserve to know this and understand how their own experience may be misleading."
In this study, the scientists tracked 491 smokers who had been attending National Health Service (NHS) smoking cessation clinics in various parts of England. They had all been given nicotine patches and attended appointments every week. 106 of them (21.6%) had been diagnosed with mental health problems before they attempted to quit smoking, mainly anxiety and mood disorders.
At the beginning of the study, all the participants were assessed for their anxiety levels. They were also asked whether they smoked because of 'mainly pleasure', 'mainly to cope', or 'about equal'.
Sixty-eight (24%) of the participants had managed to remain smoke-free six months later. Ten of them had a current psychiatric disorder.
The authors reported a considerable difference in anxiety levels among those who had successfully given up smoking compared those who had not.
The successful quitters showed a drop in anxiety. The decrease in anxiety was particularly noticeable among the ex-smokers who used to smoke "to cope", compared to those who used to smoke "for pleasure".
Among those who started smoking again, those who smoked "for pleasure" experienced no change in anxiety levels after relapsing. However, the ones who smoked "to cope", as well as the participants with a diagnosed mental health problem showed an increase in anxiety.
Those who smoked to cope - were much more likely to have a cigarette as soon as they woke up in the morning. The researchers say this behavior aims to "stave off withdrawal symptoms, including anxiety". If they managed to give up smoking, these repeated episodes of anxiety were eventually removed and they felt less anxious.
Regarding the participants who had relapsed and experienced higher levels of anxiety, the authors wrote:
"There is no obvious causal mechanism other than those who relapse feeling concern arising from the continuing health risks of their smoking.
(conclusion) In summary, stopping smoking probably reduces anxiety and the effect is probably larger in those who have a psychiatric disorder and who smoke to cope with stress. A failed quit attempt may well increase anxiety to a modest degree, but perhaps to a clinically relevant degree in people with a psychiatric disorder and those who report smoking to cope.
Clinicians should reassure patients that stopping smoking is beneficial for their mental health, but they may need to monitor for clinically relevant increases in anxiety among people who fail to attain abstinence."
Studies have produced conflicting findings regarding its effects on anxiety. Scientists at Virginia Commonwealth University say they found that inactivation of beta2 subunit, a sub-class of nicotine receptors that bind nicotine, seems to reduce anxiety. They believe that nicotine may be acting through inactivation, rather than activation.