Psychiatric Disorders Have Increased in Declining Smoker Population

People who began smoking in the 1980s or later have an increased likelihood of having a psychiatric or substance use disorder compared with those who began smoking in earlier decades, according to research published in Molecular Psychiatry.

“Our study confirms that recent smokers, though a relatively smaller group than those who started smoking decades ago, are more vulnerable to psychiatric and substance use disorders,” said Ardesheer Talati, PhD, assistant professor of clinical neurobiology in Psychiatry at Columbia University Medical Center (CUMC) and New York State Psychiatric Institute (NYSPI), in a statement.

Although smoking rates have declined since the 1960s, the researchers found that the proportion of smokers dependent on nicotine has increased. They also found that regardless of whether smokers were dependent on nicotine, the likelihood that they had a substance use disorder increased with each decade.

In addition, nicotine-dependent smokers who began smoking in the 1980s were more likely than smokers who began prior to the 1980s to have a psychiatric condition, such as bipolar disorder, antisocial personality disorder, or attention deficit hyperactivity disorder (ADHD).

“These findings suggest that today’s adolescent and young adult smokers may benefit from mental health screening so that any related psychiatric or substance use problems can be identified and addressed early,” Dr Talati said.

Smoking rates in the United States declined starting in the 1960s due to recognition of associated health risks and a corresponding stigma;: in the 1950s, nearly half of the U.S. population smoked, compared with just 20% of the U.S. population today.

To see if people who began smoking in later decades were more susceptible to psychiatric and substance use disorders, researchers from CUMC and NYSPI investigated 25 412 participants from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC). The researchers classified the participants according to birth decade (1940s, 1950s, 1960s, 1970s, and 1980s) and into 3 smoking categories (nonsmokers, never-dependent smokers, and ever-dependent smokers). They interviewed participants using the Alcohol Use Disorder and Associated Disabilities Interview Schedule – DSM-IV Version (AUDADIS-IV).

The researchers’ findings suggest that people who began smoking in more recent decades have a “disproportionately high psychiatric vulnerability,” and may benefit from increased mental health screenings. The researchers also noted that “differentiating between casual and dependent smokers may further help prioritize those at greatest risk.”

“These findings also have implications for ongoing nationwide efforts to support smoking cessation efforts,” said Katherine Keyes, PhD, assistant professor of Epidemiology at Columbia’s Mailman School of Public Health in a statement. “Given that mental health problems are also predictive of unsuccessful efforts to reduce or quit smoking, these findings suggest that cessation efforts that treat both withdrawal from nicotine and underlying mental health conditions are increasingly crucial.”

The researchers noted that further studies are needed to determine whether biological or genetic factors affect the rates of mental health or substance use problems in smokers.

Reference

Talati A, Keyes KM, Hasin DS. Changing relationships between smoking and psychiatric disorders across twentieth century birth cohorts: clinical and research implications. Mol Psychiatry. 2016; doi:10.1038/mp.2015.224.