Linking Brain Morphometry to Psychometric Measures and Energy-Metabolic Biomarkers in Adults With Autism Spectrum Disorder.

One scan and one blood test at a single point in time. The study can show that things go together, not that one causes the other, so it says nothing about whether metabolic or brain differences drive autism traits. The sample was smaller than the large multicentre imaging studies, so small or moderate differences between groups may have been missed, especially in the subgroup analyses. The childhood-ADHD-to-cortex finding disappeared once antipsychotic medication was taken into account, and the eight autistic participants on antipsychotics had the highest childhood ADHD scores. The adjustment may have removed the very effect it was meant to control for, so this result is unstable either way. There was no comparison group of people with other conditions such as ADHD, so the findings cannot be said to be specific to autism. Childhood ADHD symptoms were asked about in adulthood, so they depend on memory and may over- or under-state what was actually happening in childhood. Diet affects carnitine levels, particularly meat intake, and diet was not measured or controlled, so the acylcarnitine results could reflect what people ate rather than how their metabolism works. The study recorded no information on age at diagnosis, childhood symptom severity or therapy history, all of which could shape adult brain structure. The autistic group was on average older than the comparison group, although age was adjusted for in the analyses.

Funded by the German Research Foundation (Deutsche Forschungsgemeinschaft; grants MA 7813/1-1 and TE 280/15-1). One author sits on the Neurotorium editorial board funded by the Lundbeck Foundation. Another reports advisory board roles, lectures or travel grants in the past three years from Roche, Eli Lilly, Janssen-Cilag, Novartis, Shire, UCB, GSK, Servier, Janssen and Cyberonics. The remaining authors declare no conflicts of interest.

Do not read the childhood ADHD result as proof that ADHD thins the cortex in autistic adults. The link disappeared once antipsychotic medication was accounted for, the eight autistic participants on antipsychotics had the highest childhood ADHD scores, and the study measured people only once, so it cannot show cause and effect. The acylcarnitine results are likewise only correlations from a single blood test and scan. Nothing here shows that diet, carnitine or any supplement changes brain structure.