Stimulants May Reduce Smoking Risk in ADHD Patients

A new meta-analysis finds that patients with ADHD are significantly less likely to smoke if they take stimulant medications—and that the effect is even stronger with consistent adherence.

Patients with attention-deficit/hyperactivity disorder (ADHD) who are treated with stimulant medications may be less likely to develop a smoking habit, according to the results of a recent meta-analysis. The study, published online on May 12, 2014, in Pediatrics, found that the association was particularly strong among patients who were consistently adherent to the medications.

Patients diagnosed with ADHD are significantly more likely to smoke cigarettes, and the effects of stimulant treatment on smoking risk are a matter of ongoing debate. To evaluate this relationship, the researchers reviewed studies comparing psychostimulant treatment among ADHD patients published from 1980 through July 2013. The studies included in the analysis also measured the prevalence of smoking among treatment and control groups. Previous studies have used nicotine dependence to measure smoking behavior among adolescents treated with stimulants, a potentially flawed approach as many adolescents who smoke have not developed full nicotine dependence yet. To measure smoking behaviors more accurately, researchers working on the meta-analysis looked at smoking frequency and current smoking status.

Among 17 studies included in the overall review, 9 indicated that stimulant treatment was associated with lower rates of smoking or later smoking onset. Only 1 study found an association between increased smoking rates and stimulant treatment, and 5 found no association.

A total of 14 longitudinal studies including 2360 patients diagnosed with ADHD had sufficient statistical information to be included in the meta-analysis. The results indicated that youth who had ever been treated with stimulants were significantly less likely to smoke than were those who had never been treated with stimulants. The association between stimulant treatment and reduced smoking risk was stronger in studies that measured smoking prevalence during adolescence rather than young adulthood, studies that accounted for comorbid conduct disorder, and those including fewer male patients. The effect also appeared to be stronger when patients were consistently adherent to the medications.

These findings are consistent with previous studies that have shown that stimulant medications do not increase the risk of smoking among ADHD patients and may actually decrease the risk, the authors of the meta-analysis note. More research is needed, however, to understand the relationship between stimulant use and smoking risk and to eliminate possible confounders that were not accounted for in the meta-analysis. Although the results support consistent use of stimulants to treat ADHD, treatments for the disorder are underused and long-term adherence is poor, the authors note.

“Strategies to improve treatment engagement and retention for youth with ADHD may not only maximize the effectiveness of medication, but could have additional benefits to reduce the smoking risk status of this population,” they conclude.