Low serum sphingolipids in children with attention deficit-hyperactivity disorder

Background: Attention deficit-hyperactivity disorder (ADHD) is the most prevalent neuropsychiatric condition in childhood. ADHD is a multifactorial trait with a strong genetic component. One neurodevelopmental hypothesis is that ADHD is associated with a lag in brain maturation. Sphingolipids are essential for brain development and neuronal functioning, but their role in ADHD pathogenesis is unexplored. We hypothesized that serum sphingolipid levels distinguish ADHD patients from unaffected subjects. Methods: We characterized serum sphingolipid profiles of ADHD patients and two control groups: non-affected relatives and non-affected subjects without a family history of ADHD. Sphingolipids were measured by LC-MS/MS in 77 participants (28 ADHD patients, 28 related controls and 21 unrelated controls). ADHD diagnosis was based on the Diagnostic and Statistical Manual of Mental Disorders (DSM IV-TR). Diagnostic criteria were assessed by 2 independent observers. Groups were compared by parametrical statistics. Results: Serum sphingomyelins C16:0, C18:0, C18:1, C24:1, ceramide C24:0 and deoxy-ceramide C24:1 were significantly decreased in ADHD patients at 20-30% relative reductions. In our sample, decreased serum sphingomyelin levels distinguished ADHD patients with 79% sensitivity and 78% specificity. Conclusions: Our results showed lower levels of all major serum sphingomyelins in ADHD. These findings may reflect brain maturation and affect neuro-functional pathways characteristic for ADHD

Intra-individual response variability assessed by ex-gaussian analysis may be a new endophenotype for Attention Deficit / Hyperactivity Disorder

Intra-individual variability of Response Times (RTisv) is considered as potential endophenotype for Attentional Deficit/Hyperactivity Disorder (ADHD). Traditional methods for estimating RTisv lose information regarding Response Times (RTs) distribution along the task, with eventual effects on statistical power. Ex-Gaussian analysis captures the dynamic nature of RTisv, estimating normal and exponential components for RT distribution, with specific phenomenological correlates. Here, we applied ex-Gaussian analysis to explore whether intra-individual variability of RTs agrees with criteria proposed by Gottesman and Gould for endophenotypes. Specifically, we evaluated if Normal and/or exponential components of RTs may a) Present the stair-like distribution expected for endophenotypes (ADHD>Siblings>Typically Developing children (TD) without familiar history of ADHD) and b) Represent a phenotypic correlate for previously described genetic risk variants. This is a pilot study including 55 subjects (20 ADHD-discordant sibling-pairs and 15 TD children), all aged between 8 and 13 years. Participants resolved a visual Go/Nogo with 10% Nogo probability. Ex-Gaussian distributions were fitted to individual RT data and compared among the three samples. In order to test whether intra-individual variability may represent a correlate for previously described genetic risk variants, VNTRs at DRD4 and SLC6A3 were identified in all sibling pairs following standard protocols. Groups were compared adjusting independent general linear models for the exponential and normal components from the ex-gaussian analysis. Identified trends were confirmed by the non-parametric Jonckheere-Terpstra test. Stair-like distributions were observed for μ (p=0.036) and σ (p=0.009). An additional DRD4-genotype X clinical status interaction was present for τ (p=0,014) reflecting a possible severity factor. Thus, Normal and exponential RTisv components are suitable as ADHD endophenotypes

América Latina : sociedad, política y salud en tiempos de pandemia

Actualmente es indiscutible que la pandemia de COVID-19 es el acontecimiento contemporáneo de salud más importante. Ha irrumpido con fuerza en la cotidianidad de los países, ciudades, comunidades y familias. Sin embargo, parece necesario tener presente que es un advenimiento en progreso y no tenemos certeza sobre el curso que tomará y cuales serán sus ulteriores efectos. Esto significa que cualquier reflexión sobre COVID-19 es preliminar. Con el transcurrir de los últimos seis meses la pandemia se ha convertido en tema obligado en las primeras planas de los periódicos. Ha desatado un debate en el cual muchos se sienten con la competencia para opinar, apoyar o rechazar la actuación de los gobiernos. Ante los cuestionamientos los gobiernos han creado su propia narrativa sobre lo que están haciendo. La pandemia es en este sentido un tema altamente politizada. La epidemia de SARS-CoV-2 confluye con otro proceso de largo alcance que es la transformación de inspiración neoliberal de los sistemas de salud desde por lo menos tres o cuatro décadas. Otro proceso en los orígenes de la epidemia es el acelerado deterioro del medio ambiente y el calentamiento global que está trastocando los ecosistemas en todo el planeta. En su determinación está entonces la confluencia de tres grandes procesos que caracterizan a la globalización. Éstos a su vez se irradian en toda la sociedad y tienen efectos sobre otros procesos. Del prólogo de Asa Cristina Laurel