Stopping smoking boosts mental health, study finds

When people give up smoking, their mental health improves, according to a new cohort study of 4,260 people from the University of Oxford.

People experience substantial improvements in their depression and anxiety scores between nine and 24 weeks after smoking cessation  – and the effect holds true for both those with and without diagnosed psychiatric conditions, the researchers found. The scores were 0.40 point lower for anxiety and 0.47 point lower for depression on the Hospital Anxiety and Depression Scale (HADS) after adjusting for confounding factors. “We used three statistical approaches to reduce confounding, so that we provided more robust evidence about the effects of quitting smoking on mental health. Quitting smoking will not worsen and may improve mental health outcomes,” the study’s co-author, Min Gao, said.

The mean age of the people in the study was 46. Nearly three-quarters (71.5%) were white while 58% were female. More than half (55.4%) had a history of mental illness, and 923 (21.7%) were currently prescribed psychotropic medication. The authors used a longitudinal cohort design with individual-level patient data from the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) – a double-blind, randomized, placebo-controlled clinical trial of smoking cessation medications. Only data collected in the US was available for the Oxford study.

The authors note that smoking is the “leading cause of preventable disease and death in the world” with “1 in every 2 people who continue smoking through life dying from a smoking-related disease.”

‘Widespread’ belief that smoking is calming

There is a popular belief that smoking can alleviate stress and have a calming effect, leading some people who have mental health problems to avoid giving up the habit. “Feelings of low mood, irritability, and anxiety can manifest shortly after finishing a cigarette when blood levels of nicotine drop and these feelings are relieved by smoking another cigarette,” the authors write. “Therefore, individuals may perceive that smoking relieves their psychological distress; however, this distress may have been caused by smoking withdrawal. The belief that cigarettes are calming is widespread, and some health professionals may deter people with mental health disorders from trying to stop smoking.”

The lead author of the study, Angela Wu, said that while the number of people smoking has dropped in the UK, the proportion of smokers who also have a mental health condition has remained constant at about 40% between 1993 and 2013. “Given that the rate of smoking in people with diagnosed psychiatric disorders is not decreasing as quickly as in the general population, it is essential to assess whether cessation affects mental health, particularly in people with psychiatric disorders,” the authors write.

It has also been shown that people with mental health problems die earlier than those without, they add: “The disparity between smoking cessation rates in people with and without psychiatric disorders is concerning, given that smoking may account for up to two-thirds of the difference in life expectancy between people with a history of psychiatric disorders who smoke vs people who have never smoked.”

There is a caveat, however: participants were included in the study only if they were not currently experiencing a mental illness, so the results, the paper says, “may not generalize to those with current illness.”.

“We hope our results can help motivate policymakers and stakeholders to better support smoking cessation in people with mental health conditions,” said Wu.