Stimulants Linked to Lower Smoking Risk in Kids With ADHD

Larry Hand

May 14, 2014

Consistent treatment with stimulants in youth with attention-deficit/hyperactivity disorder (ADHD) may lower the risk for smoking, new research suggests.

In the largest meta-analysis to date examining the relationship between stimulant medication treatment and smoking outcomes in ADHD, investigators at Duke University School of Medicine, Durham, North Carolina, found a significant association between treatment with stimulants and lower smoking rates.

"Our study shows that there is a relationship between being treated for ADHD with stimulants and lower rates of smoking, but we can't conclude that medication directly caused smoking to be reduced," first author Erin N. Schoenfelder, PhD, told Medscape Medical News.

The findings were published online May 12 in Pediatrics.

Mitigating Effect?

Previous research has shown that youth with ADHD are 2 to 3 times more likely to smoke as their counterparts without ADHD. Further, they are more likely to start smoking at a younger age, the researchers note.

To examine the relationship between smoking and use of psychostimulants commonly prescribed to treat ADHD, the investigators reviewed 17 studies that compared cigarette smoking outcomes in stimulant-treated and untreated youth with ADHD. Fourteen studies were included in the meta-analysis.

The meta-analysis included data on 2360 participants, including 1424 treated and 936 untreated individuals. Overall, participants ranged in age from 4 to 18 years; the studies' follow-up periods ranged from 2 to 26 years.

Nine studies showed that stimulant treatment was associated with lower rates or later smoking onset, 5 showed no association, and 3 showed mixed results.

The pooled random effect odds ratio (OR) of smoking by treated vs untreated youth turned out to be 0.54 (95% confidence interval [CI], 0.38 - 0.78).

In metaregression analysis, the researchers found a stronger protective effect in adolescents compared with young adults (P < .05) and in girls compared with boys (P < .01).

The researchers also found a greater protective effect in participants from clinics compared with community-based participants (P < .01), indicating that such an association may be more profound in patients with more severe disorders.

"The protective effect of stimulants against smoking was stronger for studies that conceptualized treatment as consistent versus those comparing ever-treated to never-treated youth," the researchers write. "It is possible that reduced smoking among medicated youth occurs because ADHD symptoms and impairment are effectively mitigated by medication."

Stimulants Only a Starting Point

But the overall message from this study is broader than just taking medicine, Dr. Schoenfelder said.

"There is no compelling research evidence against treating ADHD with medication or taking stimulant medication consistently. We are continuing to learn more about benefits of medication treatments that go beyond managing ADHD symptoms. Our findings show that the benefits may be greater when medication is taken consistently over time, into adolescence and young adulthood," said Dr. Schoenfelder.

Further, she said, prescribing stimulants to kids with ADHD is merely a starting point.

"Clinicians can play an important role in helping families understand their treatment, be engaged in the treatment process, and keep communicating with their physicians as their children's needs change over time.

"It's important to note that the children who benefited from stimulants in these studies were diagnosed with ADHD through careful and thorough diagnostic evaluations. We can't conclude that medication will have these benefits for all children out there who are prescribed stimulants, and it is crucial to use formal diagnostic procedures to make sure that ADHD is truly what is causing the difficulties.

"Further studies are needed to find out whether it is the medication itself, rather than related factors such as parent involvement or having access to good treatment resources, that caused the risk to be lower. When we are more certain about what is causing this effect, we can create programs to help prevent smoking for young people with ADHD," she added.

Important Distinction

Commenting on the findings for Medscape Medical News, Paul Hammerness, MD, a child psychiatrist at Children's Hospital of Boston, Massachusetts, and assistant professor of psychiatry at Harvard Medical School, said the study highlights "an important distinction between 'treated' for ADHD and taking medication on a very consistent, daily basis."

"It makes intuitive sense that taking the medication intermittently would be less likely to be effective for basic ADHD as well as having broader impact. These medications tend to work when they are in the system and not when they are not — vs some medications which can have longer effects perhaps because they accumulate and stay in the body longer," said Dr. Hammerness, who was not involved in the research.

The results of the study can serve as "an important reminder of the role [primary care physicians] and child psychiatrists should play in conversations about the health and functioning of children with ADHD — that for a given child with ADHD, the increased risk of smoking may be the most significant effect of the disorder over the course of his/her life. And that treatment may change the risk," Dr. Hammerness said.

Dr. Hammerness and Dr. Schoenfelder report no relevant financial relationships. The disclosures of the other authors can be found in the original article.

Pediatrics. Published online May 12, 2014. Abstract


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