ReseaRch
Int he general adult population, the prevalence of attentiondeficit/hyperactivity disorder (ADHD) is approximately 2% to 4%. [1][2][3][4] Methylphenidate (MPH) effectively ameliorates many symptoms of adult ADHD. [5][6][7][8][9] In 1l arge 6-week randomized controlled trial of adults with ADHD,7 immediate-release methylphenidate (IR-MPH) was associated with a76% response rate, compared with a1 9% response rate for placebo. In a 6-week trial with the same response criteria, 66% of subjects treated with osmotic release oral system methylphenidate (OROS-MPH) responded, compared with 39% who received placebo.
9In both studies, response was defined as a3 0% symptom reduction and, at least, much overall improvement.Early discontinuation of treatment is common in the community careo fp atients initiating stimulant therapy. [10][11][12][13] In 1s tudy, BACKGROUND: Although stimulant therapyiscommonly discontinued early in adults with attention-deficit/hyperactivity disorder (ADHD), the factors that contribute to continuity of stimulant therapyremain largely unknown.OBJECTIVE: To (1) comparethe continuity of methylphenidate (MPH) therapy among adults who use immediate-release methylphenidate (IR-MPH) for ADHD with adults who use extended-release methylphenidate (ER-MPH) formulations, and (2) RESULTS: Less than one third(30.0%) of the adult patients who were prescribed MPH had 1ormoremedical claims with adiagnosis code for ADHD.For the adult MPH patients with at least 1medical claim with a diagnosis code for ADHD,the patients who initiated therapywith ER-MPH (N =2,833) weresignificantly younger,weremorelikely to be male,and were less likely to be treated by apsychiatrist than werethe patients who initiated therapywith IR-MPH (N =2,289). Only 50.5% (n =1,156) of IR-MPH patients and 61.4% (n =1,739) of ER-MPH patients had morethan 1pharmacyclaim for the indexMPH medication. Adults treated with ER-MPH also had a significantly longer median duration of treatment with the indexmedication (ER-MPH: 68 days, 95% confidence interval [CI], 65-71 days vs. IR-MPH 39 days, 95% CI, 33-52 days). Controlling for group differences in age,gender, treatment by apsychiatrist, recently prescribed psychotropic medications, treated mental disorders, emergencymental health treatment, and inpatient mental health care, ER-MPH initiation wasassociated with an average 27% longer duration of treatment than with IR-MPH (survival time ratio: 1.27, 95% CI, 1.20-1.35).CONCLUSION: In management of adult ADHD,use of ER-MPH formulations wasassociated with alonger median duration of the initially prescribed medication than wasuse of IR-MPH. It is unknown whether the observed absolute unadjusted difference of 29 days in median length of therapyis clinically important.
