Stimulant Drug Response in the Predominantly Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

Abstract

Objective: This study compared the methylphenidate (MPH) dose-response profiles of children with the Predominantly Inattentive (PI) and Combined (CB) subtypes of attention-deficit=hyperactivity disorder (ADHD). It is the first such study to enroll a sample comprised exclusively of children, all but one of whom had no prior exposure to ADHD medications. Method: The design was a double-blind crossover with 1-week exposures to placebo and low, medium, and high, fixed, three times daily (t.i.d.) dosage regimens of immediate-release MPH, administered in random order. Parents and teachers completed weekly behavioral questionnaires (Conners, Swanson, Kotkin, Agler, M-Flynn and Pelham Scale [SKAMP]) and a child psychiatrist provided weekly ratings of symptom severity (ADHD Rating Scale [ADHD-RS]), side effects (Side Effects Rating Scale), and a Clinical Global Impressions-Severity (CGI-S). In addition, laboratory measures of vigilance (Continuous Performance Test [CPT]) and resistance to cognitive interference (Stroop) were administered weekly. Results: Twenty-five children (15 CB, 10 PI), who met rigorous diagnostic criteria for their ADHD subtype, completed the study. Groups did not differ on demographic variables or severity at baseline. Behavioral questionnaires and clinical ratings indicated significant improvement on MPH for both subtypes but no differences in response profiles of the two groups. Drug effects were predominantly linear for both subtypes. Effects of MPH were significant for the CPT, but not the Stroop, instrument with no differences between ADHD subtypes. Conclusions: Results support the clinical utility of MPH in the treatment of the PI subtype and provide no evidence of differences in response between the subtypes.

Dose Effects and Comparative Effectiveness of Extended Release Dexmethylphenidate and Mixed Amphetamine Salts

“…This is consistent with several (e.g., Stein et al 2003;Newcorn et al 2010), but not all (i.e., Solanto et al 2009), previous studies that examined dose-response by ADHD symptoms domains by dose. (2) …”

ADHD and Factor Analysis: Are There Really Three Distinct Subtypes of ADHD?

“…Overall, the evidence for different cognitive profiles is not compelling and the subtypes are more similar than different with regard to their neuropsychogical profiles (Adams et al; Barkley & Murphy;Derefinko et al;Lemiere et al;Solanto et al, 2007). Additionally, the groups show similar response to medication (Solanto et al, 2009).…”

Role of computerised continuous performance task tests in ADHD

“…[16][17][18][19] CPT tests have a potential role in monitoring the need for ongoing therapy in children with ADHD after a prolonged period of stimulant pharmacotherapy. 20 Few studies have demonstrated the superiority of CPT tests for assessing the effects of psychostimulants in ADHD patients over other laboratory tools for measuring vigilance such as 21 A recent review has presented a balanced view of the usefulness and limitations of CPT tests in monitoring the effects of psychostimulants. 22 Using OPtax (the research model of the CPT test QbTest), statistically significant results were found for micro-events, spatial scaling, errors of commission, accuracy and variability after methylphenidate treatment in children with ADHD.…”