A long-term lisdexamfetamine analysis reported high response and remission percentages, but the percentage depended on which participants and time period were counted. Reaching a symptom cutoff at least once is different from maintaining it throughout follow-up.
Mattingly and colleagues analyzed a four-week placebo-controlled adult ADHD trial and a subsequent open-label extension. The extension included dose optimization followed by maintenance. These were post hoc analyses of existing studies, not a new randomized year-long comparison.
Response combined at least 30% symptom reduction with a favorable global-improvement rating. Symptomatic remission required an ADHD Rating Scale IV score at or below 18. That definition differs from stricter remission cutoffs used in other publications.
Among 327 extension participants with evaluable maintenance-phase data, 85.0% met the remission criterion during the analysis period. The report also described 65.7% maintaining remission among participants who completed dose optimization.
Those figures should not be collapsed into a claim that 85% of everyone starting treatment remained continuously well for a year. The full extension efficacy population was 345, and final-visit status, ever attaining a criterion and sustained status are distinct summaries.
People continuing into an extension are selected by earlier participation and tolerability. Without a continuing randomized placebo comparator, the long-term observations cannot isolate treatment effects from selection and other time-related factors.
The studies were industry funded and involved selected adults with ADHD. Rating-defined remission does not establish recovery in every functional domain or persistence after medication stops. A reliable account states the numerator, denominator, criterion and time frame before interpreting a remission percentage.
See a randomized-withdrawal approach to maintenance.
Clinical response and symptomatic remission in short- and long-term trials of lisdexamfetamine dimesylate in adults with attention-deficit/hyperactivity disorder. doi:10.1186/1471-244X-13-39.