You hear it whenever talk of quitting comes around, "Smoking helps relax me. I get anxious whenever I quit." But experts at Oxford and Cambridge Universities and Kings College in London completed a study showing the opposite is true; that anxiety levels actually decrease when you quit smoking.
The feeling of relaxation comes not from the cigarette, but from giving your body the nicotine it craves. According to an article on NHS Choices, ""Many addiction experts argue that the perceived beneficial effects of smoking are actually due to the physical and psychological cravings for nicotine being relieved. They put forward the case that cigarettes actually create higher levels of stress and that they only offer temporary relief before more cravings occur." 
Researchers looked at 491 smokers who were attending or using some type of smoking cessation program. A little more than 20 percent of the smokers had a diagnosed mental illness - primarily mood disorders or anxiety. The smokers were characterized in three groups: those who smoked for pleasure, those who smoked to cope or those who smoked for both reasons. Anxiety levels of all participants were measured at the beginning of the study.
Sixty-eight successfully quite smoking for at least 6 months and experienced a drop in anxiety levels - 10 participants who quit had been diagnosed with a mental disorder. Those who smoked "to cope," including those with depression or anxiety, experienced a more significant decrease in anxiety than those who smoked for pleasure. Researchers stated that smoking was used to "stave off withdrawal symptoms, including anxiety,"  but that after repeated episodes of not having a cigarette, the feelings of anxiety disappeared.
The participants who relapsed and began smoking again experienced an increase in anxiety. Although the reasons were not clear, researchers thought participants may have been anxious because they knew smoking increased health problems and that they worried about the health risks.
The researchers found this study to be of interest because many times those with mental disorders, such as depression or anxiety, are not encouraged to quit smoking because it was seen as a coping mechanism. Doctors can use the information in this study to explain and reassure patients that quitting smoking is not only good for them physically but can improve mental health issues as well.
While the study is encouraging, it is important to note that only 68 participants were smoke-free after 6 months and therefore the sample size was small and larger studies may have different outcomes. The researchers also did not take other life factors, such as changes in employment or relationships, into account and such major life changes may impact the results of the study. Nonetheless, the results offer another reason to quit smoking.
"After Quitting, Smokers Calm Down," 2013, Jan7, Staff Writer, Futurity.org
"Quitting Smoking Reduces Anxiety," 2013, Jan 3, Staff Writer, Medical News Today
 "Quitting Smoking 'Reduces Anxiety Levels,'" 2013, Jan. 2, Staff Writer, NHS Choices