Effects of methylphenidate on sensitivity to reinforcement in children diagnosed with attention deficit hyperactivity disorder: an application of the matching law

The behavior of children diagnosed with attention deficit hyperactivity disorder (ADHD) has been hypothesized to be the result of decreased sensitivity to consequences compared to typical children. The present study examined sensitivity to reinforcement in 2 boys diagnosed with ADHD using the matching law to provide more precise and quantitative measurement of this construct. This experiment also evaluated the effects of methylphenidate (MPH) on sensitivity to reinforcement of children with ADHD. Subjects completed math problems to earn tokens under four different variable-interval (VI) schedules of reinforcement presented in random order under both medicated and nonmedicated conditions. Results showed that, in the medicated condition, the matching functions for both subjects resulted in higher asymptotic values, indicating an overall elevation of behavior rate under these conditions. The variance accounted for by the matching law was also higher under the medicated conditions, suggesting that their behavior more closely tracked the changing rates of reinforcement while taking MPH compared to placebo. Under medicated conditions, the reinforcing efficacy of response-contingent tokens decreased. Results are discussed with respect to quantifying behavioral changes and the extent to which the drug interacts with prevailing contingencies (i.e., schedule values) to influence behavioral variability.     

A laboratory school comparison of mixed amphetamine salts extended release (Adderall XR) and atomoxetine (Strattera) in school-aged children with attention deficit/hyperactivity disorder

Mixed amphetamine salts extended release (MAS XR; Adderall XR) and atomoxetine (Strattera) were compared in children 6 to 12 years old with attention deficit/hyperactivity disorder (ADHD) combined or hyperactive/impulsive type in a randomized, double-blind, multicenter, parallel-group, forced-dose-escalation laboratory school study. Primary efficacy measure was the SKAMP (Swanson, Kotkin, Agler, M-Flynn, and Pelham) behavioral rating scale. Changes in mean SKAMP deportment scores from baseline were significantly greater for MAS XR (n = 102) than for atomoxetine (n = 101) overall (-0.56 and -0.13, respectively; p < .0001) and at each week (p < .001). Adverse events were similar for both treatment groups. The extended time course of action and greater therapeutic efficacy of MAS XR suggests that it is more effective than atomoxetine in children with ADHD.     

Factors affecting the reliability of clinical judgments about the function of children's school-refusal behavior.

Conducted two studies to examine the interrater reliability, test-retest stability, and the effect of various clinician variables, such as years of clinical experience, theoretical orientation, and prior experience with children, on clinical judgments about the reinforcement functions of children's school-refusal behavior. Results indicated that the judgments by individual clinicians were of questionable reliability. Judgments aggregated across 3 clinicians yielded acceptable interrater and test-retest reliability in Study 1, but a greater number of clinicians were necessary to achieve acceptable reliability in Study 2. Years of clinical experience and training were the only clinician variables related to the reliability of judgments about reinforcement functions. Several recommendations for the clinical assessment of the function of children's school-refusal behavior are discussed.     

Quantitative integration of single-subject studies: Methods and misinterpretations

Derenne and Baron (1999) criticized a quantitative literature review by Kollins, Newland, and Critchfield (1997) and raised several important issues with respect to the integration of single-subject data. In their criticism they argued that the quantitative integration of data across experiments conducted by Kollins et al. is a meta-analysis and, as such, is inappropriate. We reply that Kollins et al. offered behavior analysts a technique for integrating quantitative information in a way that draws from the strengths of behavior analysis. Although the quantitative technique is true to the original spirit of meta-analysis, it bears little resemblance to meta-analyses as currently conducted or defined and offers behavior analysts a potentially useful tool for comparing data from multiple sources. We also argue that other criticisms raised by Derenne and Baron were inaccurate or irrelevant to the original article. Our response highlights two main points: (a) There are meaningful quantitative techniques for examining single-subject data across studies without compromising the integrity of behavior analysis; and (b) the healthiest way to refute or question findings in any viable field of scientific inquiry is through empirical investigation.     

Psychometric properties of an adult ADHD diagnostic interview

Although research has been conducted to support the psychometric properties of rating scales used to assess ADHD in adults, little work has been published examining semi-structured interviews to assess ADHD in adults. The present study examined the test-retest reliability and concurrent validity of the Conners Adult ADHD Diagnostic Interview for Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) in a sample (N = 30) of patients referred to an outpatient clinic. Kappa statistics for individual symptoms of inattention and hyperactivity-impulsivity were in the fair to good range for current report and retrospective childhood report. Kappa values for overall diagnosis, which included all DSM-IV symptoms, were fair for both current (adult) ADHD diagnosis (kappa = .67) and childhood report (kappa = .69). Concurrent validity was demonstrated for adult hyperactive-impulsive symptoms and child inattentive symptoms. The findings are discussed in the context of overall issues pertaining to adult ADHD assessment.     

Emotion Dysregulation and Emotional Impulsivity among Adults with Attention-Deficit/Hyperactivity Disorder: Results of a Preliminary Study

Recent reviews argue that emotion dysregulation is an important feature of attention-deficit/hyperactivity disorder (ADHD) and involves a failure to inhibit negative emotions that leads to negative affectively-driven impulsive behavior (i.e., emotional impulsivity). The goal of the current study was to assess (a) whether emotion dysregulation and emotional impulsivity was higher in a group of adults diagnosed with ADHD and (b) if the relationship between core ADHD symptoms (i.e., inattention and hyperactivity-impulsivity) and emotional impulsivity is mediated by emotion dysregulation symptoms. A group of adults with (n?=?18) and without (n?=?23) ADHD completed measures of core ADHD symptoms, emotion dysregulation, and emotional impulsivity. A series of one-way analyses of covariance indicated significant between-group differences in emotion dysregulation and emotional impulsivity when current depression and oppositional defiant disorder ratings were covaried. In addition, the relationship between ADHD symptoms and emotional impulsivity was mediated by emotion dysregulation symptoms. These findings suggest that emotion dysregulation and emotional impulsivity are higher in adults diagnosed with ADHD and that emotion dysregulation symptoms have predictive value beyond core ADHD symptoms.