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Abstract: Attention-deficit/hyperactivity disorder (ADHD) is linked to impaired executive functioning (EF). This is the first study to objectively investigate the effects of a long-acting methylphenidate on neurocognitive test performance of adults with ADHD. Twenty-two adults with ADHD participated in a 6-weeks study examining the effect of osmotic-release oral system methylphenidate (OROS-mph) on continuous performance tests (CPTs; objective measures), and on the self-reported ADHD rating scale (subjective measure) using a randomized, double-blind, placebo-controlled cross-over design. OROS-mph significantly improved reaction time variability (RTV), commission errors (CE) and d-prime (DP) as compared to baseline (Cohen's d>.50), but did not affect hit reaction time (HRT) or omission errors (OE). Compared to placebo, OROS-mph only significantly influenced RTV on one of two CPTs (p<.050). Linear regression analyses showed predictive ability of more beneficial OROS-mph effects in ADHD patients with higher EF severity (RTV: β=.670, t=2.097, p=.042; omission errors (OE): β=−.098, t=−4.759, p<.001), and with more severe ADHD symptoms (RTV: F=6.363, p=.019; HRT: F=3.914, p=.061). Side effects rates were substantially but non-significantly greater for OROS-mph compared to placebo (77% vs. 46%, p=.063). OROS-mph effects indicated RTV as the most sensitive parameter for measuring both neuropsychological and behavioral deficits in adults with ADHD. These findings suggest RTV as an endophenotypic parameter for ADHD symptomatology, and propose CPTs as an objective method for monitoring methylphenidate titration. [Copyright &y& Elsevier]

Background: Multisite trials, the gold standard for conducting studies in community-based settings, can mask variability across sites resulting in misrepresentation of effects in specific sites. In a placebo-controlled trial of osmotic-release oral system methylphenidate (OROS-MPH) as augmentation treatment for smokers with attention deficit hyperactivity/impulsivity disorder (ADHD), three types of sites were selected according to their clinical research specialty (ADHD, smoking cessation, and general mental health). Objective: Analysis was conducted to determine if clinical outcomes, that is, reduction in ADHD symptoms and smoking cessation rates, and the effect of treatment on these outcomes would differ by type of site. Method: A total of 255 adult smokers diagnosed with ADHD were enrolled in three clinic types: 72 in ADHD, 79 in tobacco dependence, and 104 in the mental health clinics. Results: The three site-types were similar in demographic characteristics, smoking history, baseline level of ADHD symptoms, and history of psychiatric illness. Site-type but not a site-type by treatment interaction predicted prolonged smoking abstinence. A significant three-way interaction of site-type, treatment, and time-predicted improvement in ADHD symptoms. Moderate to strong effects of OROS-MPH relative to placebo were observed in the mental health and the ADHD clinics; a weak effect was observed in the tobacco dependence clinics. Conclusion: OROS-MPH benefit varied by site for reducing ADHD symptoms but not for improving smoking abstinence. Scientific Significance: Assessment of site-type effects can indicate the generalizability of findings from multisite trials and should be routinely incorporated in the design of multisite trials. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To explore racial/ethnic difference in OROS-methylphenidate (OMPH) efficacy when added to nicotine patch and counseling for treating nicotine dependence among smokers with attention deficit hyperactivity disorder (ADHD). Method: Participants were adult smokers with ADHD (202 whites and 51 non-whites) randomly assigned to OMPH or placebo in a multi-site, randomized controlled trial. Study outcomes were complete, prolonged, and point-prevalence abstinence at the end of treatment, and weekly ratings of ADHD symptoms, tobacco withdrawal symptoms, and desire to smoke. Results: The rate of four-week complete abstinence (no slips or lapses) was significantly higher with OMPH than placebo among non-white (OMPH=42.9%, placebo=13.3%, χ 2(1)=5.20, p =0.02) but not white participants (OMPH=23.1%, placebo=23.5%, χ 2(1)=0.00, p =0.95). Patterns of prolonged and point-prevalence abstinence among non-whites were similar but fell short of statistical significance. OMPH reduced ADHD symptoms in both race/ethnic groups, and produced greater reductions in desire to smoke and withdrawal symptoms among the non-white than white participants. Change in desire to smoke, but not in withdrawal or ADHD symptoms predicted abstinence. The ability of OMPH to reduce desire to smoke among non-whites appeared to mediate the medication''s positive effect on abstinence. Conclusion: Differential efficacy favoring non-whites of a medication for achieving smoking cessation is a potentially important finding that warrants further investigation. OROS-MPH could be an effective treatment for nicotine dependence among a subgroup of smokers. [Copyright &y& Elsevier]