A large treatment-response percentage can sound like a cure rate when its definition and denominator are omitted. Mattingly and colleagues’ 2013 analyses show why adult ADHD response, symptomatic remission and maintenance need separate descriptions.
Two studies, different designs
The report reanalyzed a four-week randomized placebo-controlled trial and a subsequent open-label extension. The short trial randomized 420 adults; 414 contributed to efficacy analyses. Oral lisdexamfetamine doses were 30, 50 or 70 mg/day.
The extension enrolled 349 adults, with 345 in its efficacy population. Participants underwent dose optimization followed by maintenance. Extension findings were not an independent placebo-controlled replication of the initial experiment.
The definitions drove the percentages
Clinical response was defined post hoc as at least a 30% reduction on the ADHD rating scale plus a clinician global-improvement rating of one or two. Symptomatic remission meant a total ADHD rating score of 18 or less.
In the short trial, 69.3% receiving lisdexamfetamine met the response definition, compared with 37.1% receiving placebo. Remission percentages were 45.5% and 16.1%, respectively. Neither definition required permanent absence of symptoms or independently demonstrated normal functioning in every setting.
Any-time response is not final-visit response
In the extension, 325 of 345 met response criteria at some point, while 286 met remission criteria at some point. At the final visit, including early termination, the corresponding numbers were 285 and 227.
A participant can meet a threshold once and later cease meeting it. An any-time percentage therefore cannot be substituted for an endpoint percentage or a continuous-maintenance percentage.
Maintenance used a selected subgroup
The maintenance analyses excluded participants without evaluable maintenance data. Among those already classified as responders at entry to maintenance, 209 of 278, or 75.2%, did not subsequently lose response under the reported rule. For remission, 140 of 213, or 65.7%, did not lose remission.
These percentages describe selected initial achievers. Reporting them as the percentage of all enrolled adults who remained well for a year would change the denominator and overstate the evidence.
What should remain uncertain?
The definitions were post hoc, the extension was open label, and treatment discontinuation and selection affect interpretation. The analysis establishes symptom-scale patterns under historical research conditions, not permanent recovery or an individual prognosis.
For a client-ready explanation, specify the threshold, observation window and eligible population whenever quoting a percentage. This report does not establish driving safety, work capacity or a current prescribing recommendation.
Scientific source
Mattingly GW, Weisler RH, Young J, et al. Clinical response and symptomatic remission in short- and long-term trials of lisdexamfetamine dimesylate in adults with attention-deficit/hyperactivity disorder. BMC Psychiatry. 2013;13:39. doi:10.1186/1471-244X-13-39. Original commentary on the supplied paper.
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