Introduction
cognitive behavior, neurodevelopmental syndrome, Attention-deficit/hyperactivity disorder, impulsivity, ADHD
Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental syndrome with onset during childhood and often persists into adulthood [The treatment of adults with ADHD should follow a multimodal and multidisciplinary approach (e.g., psychoeducation, cognitive behavior therapy, coaching for ADHD and pharmacotherapy [The placebo effect is well known and a clinically important phenomenon in the patient’s treatment. Extensive research has been conducted to elucidate this [Most placebo-controlled studies have reported subjective outcomes (i.e., clinical assessments and self-report scales). Although Biederman et al., [One approach to improve assessment in ADHD is to supplement clinical judgement with computerized continuous performance tests (CPTs). The CPT is a neuropsychological assessment tool that provides an objective and standardized method for assessing attention and impulsivity. It eliminates subjective biases that can occur in self-report measures and provides quantifiable data. The CPT may be useful for monitoring the effects of ADHD treatment interventions.It is often a challenge to meet the patients’ requests for drug treatment. The medical staff needs support in their assessments to evaluate the effect of the drug for each patient. In contrast to patients’ subjective self-reports, it would be useful to have an objective tool to assess the patients’ level of response in different core signs. MPH is available as immediate release (IR-MPH), which could be suitable for medical evaluation. By offering the patient IR-MPH together with a CPT, a relatively quick response is made possible. The assessment and the results from the objective measurement can make it easier to offer adequate long-term treatment for each patient. One of several CPTs is the QbTest which is developed to measure the core symptoms of ADHD and can be used when to start a pharmacological treatment with a new patient [Placebo responses in earlier studies were found to increase toward the end of the treatment periods [The aim of the present study was to examine the effects of one single-dose IR-MPH compared to one single-dose placebo on performance in ADHD core symptoms during clinical assessments in adults with untreated ADHD. We assumed that IR-MPH would improve participants´ performance in the cardinal parameters QbActivity and QbInattention. Regarding placebo, we hypothesized that the placebo response would be lower compared to IR-MPH but effective in all three core symptoms. The placebo response would be higher at the beginning of the task, then decrease towards the end because adults with ADHD often have difficulty focusing for a longer period. Throughout this paper, we will use the term “placebo response” as to the outcome of a clinical trial.