Challenges in replication: Does amygdala gray matter volume relate to social network size?

In this work, we tried to replicate and extend prior research on the relationship between social network size and the volume of the amygdala. We focused on the earliest evidence for this relationship (Bickart et al., Nature Neuroscience 14(2), 163-164, 2011) and another methodologically unique study that often is cited as a replication (Kanai et al., Proceedings of the Royal Society B: Biological Sciences, 279(1732), 1327-1334, 2012). Despite their tight link in the literature, we argue that Kanai et al. (Proceedings of the Royal Society B: Biological Sciences, 279(1732), 1327-1334, 2012) is not a replication of Bickart et al. Nature Neuroscience 14(2), 163-164 (2011), because it uses different morphometric measurements. We collected data from 128 participants on a 7-Tesla MRI and examined variations in gray matter volume (GMV) in the amygdala and its nuclei. We found inconclusive support for a correlation between measures of real-world social network and amygdala GMV, with small effect sizes and only anecdotal evidence for a positive relationship. We found support for the absence of a correlation between measures of online social network and amygdala GMV. We discuss different challenges faced in replication attempts for small effects, as initially reported in these two studies, and suggest that the results would be most helpful in the context of estimation and future meta-analytical efforts. Our findings underscore the value of a narrow approach in replication of brain-behavior relationships, one that is focused enough to investigate the specifics of what is measured. This approach can provide a complementary perspective to the more popular "thematic" alternative, in which conclusions are often broader but where conclusions may become disconnected from the evidence.

Association of the COVID-19 Pandemic With Adolescent and Young Adult Eating Disorder Care Volume.

Importance: The COVID-19 pandemic has affected youth mental health. Increases in site-specific eating disorder (ED) care have been documented; however, multisite studies demonstrating national trends are lacking. Objective: To compare the number of adolescent/young adult patients seeking inpatient and outpatient ED care before and after onset of the COVID-19 pandemic. Design, Setting, and Participants: Using an observational case series design, changes in volume in inpatient and outpatient ED-related care across 15 member sites (14 geographically diverse hospital-based adolescent medicine programs and 1 nonhospital-based ED program) of the US National Eating Disorder Quality Improvement Collaborative was examined. Sites reported monthly volumes of patients seeking inpatient and outpatient ED care between January 2018 and December 2021. Patient volumes pre- and postpandemic onset were compared separately for inpatient and outpatient settings. Demographic data such as race and ethnicity were not collected because this study used monthly summary data. Exposures: Onset of the COVID-19 pandemic. Main Outcomes and Measures: Monthly number of patients seeking inpatient/outpatient ED-related care. Results: Aggregate total inpatient ED admissions were 81 in January 2018 and 109 in February 2020. Aggregate total new outpatient assessments were 195 in January 2018 and 254 in February 2020. Before the COVID-19 pandemic, the relative number of pooled inpatient ED admissions were increasing over time by 0.7% per month (95% CI, 0.2%-1.3%). After onset of the pandemic, there was a significant increase in admissions over time of 7.2% per month (95% CI, 4.8%-9.7%) through April 2021, then a decrease of 3.6% per month (95% CI, -6.0% to -1.1%) through December 2021. Prepandemic, pooled data showed relative outpatient ED assessment volume was stable over time, with an immediate 39.7% decline (95% CI, -50.4% to -26.7%) in April 2020. Subsequently, new assessments increased by 8.1% (95% CI, 5.3%-11.1%) per month through April 2021, then decreased by 1.5% per month (95% CI, -3.6% to 0.7%) through December 2021. The nonhospital-based ED program did not demonstrate a significant increase in the absolute number of admissions after onset of the pandemic but did see a significant increase of 8.2 (95% CI, 6.2-10.2) additional inquiries for care per month in the first year after onset of the pandemic. Conclusions and Relevance: In this study, there was a significant COVID-19 pandemic-related increase in both inpatient and outpatient volume of patients with EDs across sites, particularly in the first year of the pandemic. Given inadequate ED care availability prior to the pandemic, the increased postpandemic demand will likely outstrip available resources. Results highlight the need to address ED workforce and program capacity issues as well as improve ED prevention strategies.