Meta-analysis: Stimulant meds for ADHD reduce cigarette smoking

By Anne Harding

NEW YORK (Reuters Health) - Attention deficit-hyperactivity disorder (ADHD) patients who receive consistent stimulant treatment are less likely to start smoking, according to a new meta-analysis published May 12 in Pediatrics.

"We can rest assured about one outcome, that stimulants are not going to increase the risk of cigarette smoking," Dr. Erin Schoenfelder of Duke University School of Medicine in Durham, North Carolina, one of the study's authors, told Reuters Health in a telephone interview. "There's actually evidence that they may decrease the risk of cigarette smoking in the long term."

ADHD itself is linked to an increased risk of smoking, Dr. Schoenfelder and her team point out in their report. Studies have found that young people with ADHD are two to three times more likely to smoke than their peers without ADHD. The increased risk persists into adulthood.

Several lines of evidence suggest that treating ADHD with stimulants may affect smoking risk, the authors add. A number of lab studies, including one with ADHD smokers, found stimulant treatment increased smoking, while others have found no effect.

To better understand the relationship between ADHD and smoking, Dr. Schoenfelder and her colleagues looked at 17 studies including 2,360 patients, comparing rates of smoking for individuals receiving treatment and those who were not treated. Fourteen of the studies had adequate data for inclusion in their meta-analysis.

Overall, they found, stimulant treatment was linked to a lower likelihood of subsequent smoking. Effects were strongest in studies of clinical samples, those with more female participants, and those that followed patients up in adolescence rather than adulthood. Effects were also stronger in studies in which stimulant treatment was defined as continuous, as well as those in which researchers adjusted for comorbid conduct disorder.

In all of the studies analyzed, Dr. Schoenfelder noted, patients were diagnosed with ADHD using DSM criteria, with thorough evaluations. "It's very important to make sure that we're accurately diagnosing ADHD and we're sure that that's what is causing their difficulties when we're talking about the benefits of stimulants," she said.

Further research is needed to identify the mechanisms through which stimulant treatment may reduce smoking risk, Dr. Schoenfelder and her team say. "It's plausible that the stimulants help put kids on this positive trajectory for development where they will be more successful in school, there's less stress with parents, they're making these positive peer relationships that are supportive," the investigator added. "In the long run these children may be less likely to find themselves in contact with peers who are smoking, and may be better able to resist peer pressure to smoke."

However, she added, "with the current study we can't rule out that there's a third factor that might be associated with both the stimulant treatment and smoking rates." For example, "it's always possible that there are aspects of the families of children who receive stimulant treatment that might make these children less likely to smoke."

SOURCE: http://bit.ly/1g29UfI

Pediatrics 2014.

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