A medicine can affect appetite, weight and binge-eating behavior, but those outcomes are not interchangeable. A 2016 review of lisdexamfetamine in binge-eating disorder illustrates why the outcome definition should remain attached to each claim.
A review rather than a new experiment
Guerdjikova and colleagues summarized the clinical presentation of binge-eating disorder and the evidence then available for lisdexamfetamine, a prodrug converted to d-amphetamine. The paper was a narrative review, not a newly randomized patient cohort.
Its acute-treatment discussion covered one phase II proof-of-concept trial and two phase III placebo-controlled trials. Results from those studies remain evidence reported through the review; they should not be presented as additional independent experiments performed by the reviewers.
Binge days and episodes differ
A binge day records whether the specified behavior occurred during a day. An episode count records the number of events. Multiple episodes can occur on one day, so a reduction in one outcome cannot automatically be assigned the same numerical meaning as a reduction in the other.
The reviewed trials also examined four-week binge cessation. Meeting a cessation definition during a specified final interval is different from never experiencing another episode or achieving a permanent cure.
Weight was a separate measurement
Body-weight change was assessed separately from the primary binge-eating outcomes. A reduction in weight does not itself establish reduced loss-of-control eating, and a reduction in binge days does not establish an appropriate or safe general weight-loss strategy.
In the reviewed phase II dose-ranging trial, 50 and 70 mg/day separated from placebo on the primary binge-day outcome, while 30 mg/day did not. These refer to oral lisdexamfetamine doses in a selected disorder population, not interchangeable amounts of amphetamine or evidence for illicit methamphetamine use.
Who was represented?
Participants in the reviewed acute trials were predominantly women, white and overweight or obese. Recruitment excluded important psychiatric and cardiovascular conditions. The reviewers cautioned against broad generalization.
The acute studies lasted approximately 11–12 weeks. That period cannot establish long-term maintenance, uncommon harms or outcomes in excluded populations. Adverse events and changes in vital signs were separate safety observations, not canceled out by a positive efficacy endpoint.
How should the historical evidence be described?
The review supports a careful account of the short-term trial evidence available in 2016. It should not be used as a substitute for current prescribing information or as a recommendation to use stimulants for general weight control.
A sound summary identifies the diagnostic population, dose, observation window and exact endpoint. It does not translate eating behavior into a driving-impairment measure, a blood concentration threshold or a universal amphetamine effect.
Scientific source
Guerdjikova AI, Mori N, Casuto LS, McElroy SL. Novel pharmacologic treatment in acute binge eating disorder – role of lisdexamfetamine. Neuropsychiatric Disease and Treatment. 2016;12:833–841. doi:10.2147/NDT.S80881. Original commentary on the supplied paper.
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