Verbal Memory Interference in Attention-Deficit Hyperactivity Disorder: A Meta-Analytic Review

Examination of Excessive Mind-Wandering Following Attention-Deficit and Hyperactivity Disorder Treatment in Adults

Although mind-wandering (MW) is a part of attention deficit and hyperactivity disorder (ADHD), the impact of psychostimulants on excessive MW remains unclear. We aimed to elucidate how psychostimulants impact the MW of adult ADHD patients post treatment. This cross-sectional cohort study consisted of 54 randomly selected ADHD patients who applied to our psychiatry outpatient clinic and 40 healthy controls. The ADHD patients were administered methylphenidate or atomoxetine. A Semi-Structured Sociodemographic and Clinical Data Form, the Adult ADHD Self-Report Scale (ASRS), and the Mind Excessively Wandering Scale (MEWS) were applied. Routine psychiatric assessments in the 1st, 2nd, and 3rd months of pharmacological treatment were carried out by a psychiatrist. The pre-treatment MEWS score of the ADHD patients was 26.09 ± 1.92, which significantly decreased to 12.78 ± 2.54 post-treatment (F = 715.250, p < .001). A statistically significant difference was identified between the mean pre-treatment ASRS total score (44.07 ± 10.09) and post-treatment score (27.34 ± 11.22; F = 50.364, p < .001). A lifetime history of alcohol/substance use was positively associated with the MEWS score. ADHD pharmacotherapy led to significant reductions in MW. Recognizing the interaction between MW and ADHD could help in the design of more specific and comprehensive interventions.

Increasing Health Literacy on ADHD: A Cross-Disciplinary Integrative Review Examining the Impact of ADHD on Brain Maturation, Composition and Function and Cognitive Processes Across the Life Course

There is a significant need to improve ADHD health literacy. This cross-disciplinary integrative review was conducted to synthesise the evidence on the impact ADHD has on brain maturation, composition and function as well as cognitive processes, across the life course. Although results are highly heterogenous, ADHD appears to be associated with (1) a significant delay in cortical maturation and differences in neuroanatomy that do not appear to fully resolve in adulthood, (2) atypical brain function, and (3) atypical cognitive processes. The cognitive processes implicated include working memory, inhibitory control, cognitive flexibility, alerting attention, reward processing, long-term memory, reaction time, time perception and estimation, planning, and complex decision making/problem-solving. We aim to use this data to develop a 'framework/checklist" that parents, adults and clinicians can use to identify the possible mechanisms that may be contributing to an individual with ADHD's challenges. This information can also be used to inform the content of ADHD education programs to ensure participants receive empirically-determine information from high quality review studies and meta-analysis that accurately reflects the rigor and limitations of study findings.

Genetic dissection of mutual interference between two consecutive learning tasks in Drosophila

Animals can continuously learn different tasks to adapt to changing environments and, therefore, have strategies to effectively cope with inter-task interference, including both proactive interference (Pro-I) and retroactive interference (Retro-I). Many biological mechanisms are known to contribute to learning, memory, and forgetting for a single task, however, mechanisms involved only when learning sequential different tasks are relatively poorly understood. Here, we dissect the respective molecular mechanisms of Pro-I and Retro-I between two consecutive associative learning tasks in Drosophila. Pro-I is more sensitive to an inter-task interval (ITI) than Retro-I. They occur together at short ITI (<20 min), while only Retro-I remains significant at ITI beyond 20 min. Acutely overexpressing Corkscrew (CSW), an evolutionarily conserved protein tyrosine phosphatase SHP2, in mushroom body (MB) neurons reduces Pro-I, whereas acute knockdown of CSW exacerbates Pro-I. Such function of CSW is further found to rely on the γ subset of MB neurons and the downstream Raf/MAPK pathway. In contrast, manipulating CSW does not affect Retro-I as well as a single learning task. Interestingly, manipulation of Rac1, a molecule that regulates Retro-I, does not affect Pro-I. Thus, our findings suggest that learning different tasks consecutively triggers distinct molecular mechanisms to tune proactive and retroactive interference.