A multicohort, longitudinal study of cerebellar development in attention deficit hyperactivity disorder

BACKGROUND

The cerebellum supports many cognitive functions disrupted in attention deficit hyperactivity disorder (ADHD). Prior neuroanatomic studies have been often limited by small sample sizes, inconsistent findings, and a reliance on cross-sectional data, limiting inferences about cerebellar development. Here, we conduct a multicohort study using longitudinal data, to characterize cerebellar development.

METHODS

Growth trajectories of the cerebellar vermis, hemispheres and white matter were estimated using piecewise linear regression from 1,656 youth; of whom 63% had longitudinal data, totaling 2,914 scans. Four cohorts participated, all contained childhood data (age 4-12 years); two had adolescent data (12-25 years). Growth parameters were combined using random-effects meta-analysis.

RESULTS

Diagnostic differences in growth were confined to the corpus medullare (cerebellar white matter). Here, the ADHD group showed slower growth in early childhood compared to the typically developing group (left corpus medullare z = 2.49, p = .01; right z = 2.03, p = .04). This reversed in late childhood, with faster growth in ADHD in the left corpus medullare (z = 2.06, p = .04). Findings held when gender, intelligence, comorbidity, and psychostimulant medication were considered.

DISCUSSION

Across four independent cohorts, containing predominately longitudinal data, we found diagnostic differences in the growth of cerebellar white matter. In ADHD, slower white matter growth in early childhood was followed by faster growth in late childhood. The findings are consistent with the concept of ADHD as a disorder of the brain's structural connections, formed partly by developing cortico-cerebellar white matter tracts.

Assessing the Effect of Recent Incarceration in Prison on HIV Care Retention and Viral Suppression in Two States

The prevalence of HIV among people in correctional facilities remains much higher than that of the general population. Numerous studies have demonstrated the effectiveness and acceptability of HIV treatment for individuals incarcerated in US prisons and jails. However, the period following incarceration is characterized by significant disruptions in HIV care. These disruptions include failure to link in a timely manner (or at all) to community care post-release, as well as not being retained in care after linking. We used a retrospective, propensity-matched cohort design to compare retention in care between HIV-positive individuals recently released from prison (releasees) who linked to care in Ryan White HIV/AIDS Program (RWHAP) clinics and RWHAP patients without a recent incarceration history (community controls). We also performed analyses comparing viral load suppression of those retained in both groups. This study shows that even for those who do successfully link to care after prison, they are 24 to 29 percentage points less likely to be retained in care than those already in community care. However, we found that for those who did retain in care, there was no disparity in rates of viral suppression. These findings provide valuable insight regarding how best to address challenges associated with ensuring that HIV-positive individuals leaving prison successfully move through the HIV care continuum to become virally suppressed.