A preliminary exploration of the relationship between gray and white matter neurometabolites, neuropsychological function, and functional impairment in young adults with Attention-Deficit Hyperactivity Disorder.

摘要

Attention Deficit Hyperactivity Disorder (ADHD) has gained acceptance as a neurobiological disorder, supported by a growing body of literature that documents differences in brain structure and function in individuals diagnosed with ADHD. There is growing interest in exploring patterns of neurometabolite concentrations through the methods of proton spectroscopy (1H-MRS). Previous studies have employed single voxel techniques, examining neurometabolite concentrations in small, localized regions of brain tissue. This study is the first to employ Spectroscopic Imaging (SI), which allows for acquisition of neurometabolite spectra from a larger sample of brain tissue, in the cerebral cortex of individuals diagnosed with ADHD. Nine adolescents and young adults diagnosed ADHD and twelve control participants were enrolled in the study. Similar to previous findings, the ADHD group demonstrated significant reductions in gray matter volumes of brain regions relevant for sustained attention, inhibition, and working memory. Additionally, performance on measures of visual-spatial problem solving, academic achievement, and cognitive flexibility/response inhibition was more impaired than controls. Preliminary analyses of the SI neurometabolite data revealed few significant results, but several trends were noted, including some sex-related differences in neurometabolite concentrations. As anticipated, different patterns of correlations between neurometabolite concentrations and performance on measures of attention were discovered for the ADHD group in comparison to controls. The present study also sought to extend the literature on ADHD by providing a preliminary exploration of neurometabolite concentrations in late adolescence in the context of functional impairment in young adulthood. Although many individuals report symptom remediation when they enter adulthood, functional outcomes indicate that the impact of the disorder is far reaching, impacting aspects of quality of life, academic achievement, employment, relationships, and engagement in risk behaviors. Difficulties in collection of follow-up data limited the findings regarding functional outcome and neurological correlates. Implications and ideas for future research involving 1H-MRS techniques and ADHD are discussed. Overall, the study highlights trends and patterns indicative of a unique neurometabolic profile of individuals with ADHD, suggesting that additional longitudinal research is necessary to advance our understanding of this developmental disorder.