Smoking Addiction and Mental Health Should Be Treated Together, Study Suggests

A new large-scale study may have uncovered the need to treat smoking, substance use disorders, and mental health problems together. 

Published in the journal Drug and Alcohol Dependence, the study looked at data on more than 441,000 US adults collected over the course of 11 years. While all adults experienced an increase in serious psychological distress throughout that time, those who smoked daily and had a substance use disorder experienced the highest uptick in distress.

The findings, which come amid a rise in cigarette sales, suggest that there may be potential benefits to treating mental health problems and smoking at the same time. 

The Study

For the study, researchers from Indiana University and other institutions analyzed data on 441,286 US adults. The information came from the National Survey on Drug Use and Health from 2008 through 2018.

The data included information on whether each participant had experienced symptoms of serious psychological distress (which is linked with mental illness) in the month before the survey, well as whether they had met the criteria for a substance use disorder within the previous year. 

The researchers also evaluated participants’ smoking status and broke them down into four categories: never smokers, former smokers, current daily smokers, and current non-daily smokers.

The results showed that serious psychological distress increased for all US adults in the decade leading up to 2018. This trend was consistent among non-smokers and smokers, but those who smoked had more elevated rates of serious psychological distress. 

Adults who smoked and had a substance use disorder experienced the highest rates of psychological distress during that time. Among those without substance use disorders, non-daily smokers (or smokers who lit up a cigarette fewer than 30 days in the last month) experienced the fastest increases in serious psychological distress.

The Link Between Smoking and Mental Health

While the results offer insight into the potential connection between smoking, substance use disorders, and psychological distress, experts urge caution before drawing too many firm conclusions from the data.

“It is important to reiterate that this is a cross-sectional, correlational study, so causation cannot be determined. For example, this study does not show that smoking and substance abuse causes more distress than substance abuse alone,” explains Nicole Siegfried, PhD, a licensed clinical psychologist and chief clinical officer at Lightfully Behavioral Health. 

She adds, “It would be an inaccurate and inappropriate conclusion to say that smoking causes distress and therefore eliminating smoking alleviates distress.”

Still, the results do help advance the existing understanding of the connection between on smoking and mental health. 

“Smoking has a high comorbidity rate for those with many mental illnesses including, but not limited to, attention deficit hyperactivity disorder, anxiety disorders, and depression,” says Aung Thu, MD, FACP, FASAM, medical director of the chemical dependency unit at Providence Mission Hospital. “Smoking can also reduce the therapeutic blood levels of a number of psychiatric medications and decrease the effectiveness of medication for treatment of mental health problems.”

Siegfried notes that psychological distress and cigarette use have a complex relationship and may exist in a self-perpetuating cycle, where each problem contributes to the worsening of another.

“One theory is that individuals who have psychological distress may seek out substances such as cigarettes to provide emotion regulation, soothing, and escape,” she says. “Additionally, withdrawal symptoms often mimic mental health symptoms, further increasing distress. So, over the long term, smoking (as well as other substance use) may actually exacerbate psychological distress, which creates the need for more substances or alternative substances.”

Thu adds, “Mental health disorders can also trigger the relapse of substance use disorder. The patients with substance use disorder can have difficulty staying sober if a mental health disorder is not treated.”

Putting the Findings Into Action

Despite the limitations of the study, its findings could be useful in developing new strategies to help people quit smoking and improve their mental health.

"Our study shows that there is a need for consistency in treating mental health, smoking, and substance use problems together," said Maria Parker, PhD, assistant professor at the Indiana University School of Public Health-Bloomington and lead author of the study, in a press release.

In fact, an earlier study found that integrating smoking cessation treatment into mental health care led to better outcomes for veterans with post-traumatic stress disorder (PTSD), Thu points out.

“The patients were more likely to be smoke-free 18 months later when compared with patients who attended smoking-cessation clinics separate from their PTSD treatment,” he says. 

A similar strategy could prove effective for a more general population, as well.

It could also be useful for mental health professionals and physicians to take the link between smoking and psychological wellbeing into account when screening patients, says Siegfried. 

“For instance, based on this study, primary care physicians should screen for mental health symptoms in their clients who abuse substances and who smoke,” she says.

With all that said, it’s important to note that mental health disorders don’t exist in a vacuum. People with mental illnesses are more likely to have stressful living situations, a low household income, and less access to health care—all of which can make it more challenging to quit smoking. Addressing these structural challenges is another critical step toward improving people’s health and reducing rates of smoking and substance use.