Toward Inclusion of Youths With Psychiatric Disorders in Brain-Body Research

To the Editor Laurent et al¹ reported compelling findings regarding the association of obesity with brain structure and function. The study excluded children with attention-deficit/hyperactivity disorder, schizophrenia, or autism spectrum disorder. The article does not specifically indicate whether other psychiatric disorders were evaluated. Major depressive disorder and bipolar disorder are known to confer increased risk and premature onset of cardiovascular disease. Unfortunately, these and other psychiatric conditions are perpetually overlooked when considering brain-body associations such as those illuminated by Laurent et al.¹ We wanted to alert the authors and readers of JAMA Pediatrics to 2 related prior studies. First, in a study of adolescents with bipolar disorder and healthy control adolescents,² we found a significant diagnosis by body mass index interaction on cortical thickness and volume, in similar frontal regions as those identified by Laurent et al. That is, there was significantly more negative association of body mass index with brain structure within the bipolar disorder group compared with the healthy control group. In a second study of an impulsivity-related neurocognitive task,³ we found a similar interaction effect: there was a significantly more negative association of waist circumference with poorer task performance in adolescents with bipolar disorder than in healthy control adolescents. While these were separate studies, one can see that our prior findings collectively indicate that the negative association of obesity with brain structure and function is more pronounced in adolescents with bipolar disorder than in healthy control adolescents. In our sample, healthy control adolescents had negligible variability in psychiatric symptoms, whereas we anticipate that there was a broader range within the Adolescent Brain Cognitive Development sample. In contrast to the Laurent et al study,¹ there were no obesity-related neurostructural differences in the study by Sharkey et al,⁴ and there were significant positive associations between obesity and brain structure in the study by Saute et al.⁵ We speculate that mood disorders and/or symptoms may contribute in part to heterogeneity and inconsistency of findings on the obesity-brain interface. It is not yet clear whether intervention, including cognitive remediation, cardiorespiratory exercise, pharmacologic, nutritional, and/or other approaches, intercepts the putatively deleterious effect of executive dysfunction on physical health and vice versa. We anticipate that the findings reported by Laurent et al¹ will encourage related prevention and treatment studies and hope that those studies will integrate youths with psychiatric disorders, in whom there may be enhanced benefit and value of such interventions.