Improving ADHD symptoms did not produce a demonstrated smoking-cessation advantage in a small lisdexamfetamine trial. Treating one clinical problem and changing a separate substance-use outcome are different propositions.
The pilot randomized 32 regular smokers with ADHD to lisdexamfetamine or placebo, with 17 and 15 participants in the respective groups. Both groups received nicotine patches during an attempt to quit smoking.
The question was therefore whether lisdexamfetamine added benefit beyond the study’s background cessation treatment. It was not a comparison between medication and receiving no support.
Participants assigned lisdexamfetamine had significant reductions in self-reported and clinician-rated ADHD symptoms. However, the study found no significant treatment-group differences on smoking outcomes.
Both groups reduced smoking. That common improvement cannot be attributed exclusively to lisdexamfetamine because placebo participants also received nicotine replacement and participated in the quit attempt.
The symptom benefit remains relevant even when the smoking comparison is nonsignificant. Conversely, improvement in symptoms should not be relabeled as proven cessation efficacy.
The pilot was small, so it could miss modest effects. A nonsignificant comparison is not a formal demonstration that treatments are identical. It is evidence that an added smoking benefit was not established in this protocol.
These were smokers with ADHD who wanted to quit and were using nicotine patches. The results cannot establish what happens in smokers without ADHD, people not attempting cessation or those taking a stimulant without nicotine replacement.
The paper also does not establish that better symptom scores mean improved performance on every real-world task.
The study illustrates why outcomes must remain separate even when they occur in the same people. A treatment response cannot be inferred from drug detection, and detection does not establish either smoking behavior or impairment during a particular event.
Related reading: Lisdexamfetamine and a simulated workplace task.