Scientific Papers - September 2021

This month the WFADHD highlights three papers of special interest. The paper by Vertessen et al. conducted a systematic review and meta-analysis of literature on effects of methylphenidate (MPH) on neurocognitive functioning in children with attention-deficit/hyperactivity disorder (ADHD). While treatment with psychostimulants such as MPH has been shown to improve the core symptoms of ADHD, less information is available of its effects on cognitive performance. This meta-analysis demonstrated a dose-dependent effect of MPH on all neurocognitive functions.

The paper by Fernandez et al. investigated the role of Cdk5/p35 in the expression of the dopamine transporter, the target of psychostimulants used in the treatment of ADHD. Cdk5 (Cyclin dependent kinase-5), a family member of the cyclin-dependent kinases, plays a pivotal role in the central nervous system. Functional Cdk5 gene variants have been shown to be associated with the etiology of ADHD.

The paper by Nikolova is an up-dated meta-analysis of gut microbiota alterations in patients with psychiatry disorders including ADHD. Gut-brain axis is a system widely studied nowadays. Although there are several systematic reviews of microbiota an psychiatric disorders, there are no attempts have been made yet to evaluate the specificity of gut microbiota alterations across the range of psychiatric conditions. It was found that gut microbiota perturbations were associated with a transdiagnostic pattern with a depletion of certain anti-inflammatory butyrate-producing bacteria and an enrichment of pro-inflammatory bacteria in patients with depression, bipolar disorder, schizophrenia, and anxiety.