Preserved white matter in unmedicated pediatric bipolar disorder

Abstract

White matter (WM) abnormalities have been reported in bipolar disorder (BD) patients, as well as in their non-BD relatives, both children and adults. Although it is considered an emerging vulnerability marker for BD, there are no studies investigating WM alterations in pediatric unmedicated patients and young healthy offspring. In this study, we evaluated the presence of WM alterations in 18 pediatric, non medicated BD patients, as well as in 18 healthy offspring of BD type I parents and 20 healthy controls. 3T DT-MRI data were acquired and scans were processed with tract-based spatial statistics to provide measures of fractional anisotropy and diffusivity. We found no significant differences in WM microstructure between BD patients, healthy offspring and healthy controls. Previous studies that reported WM alterations investigated older subjects, either on medication (BD patients) or with psychiatric diagnoses other than BD (unaffected offspring). Our findings highlight the importance of the understanding of disease ontogeny and brain development dynamics in the search for early vulnerability markers for psychiatric disorders.

The International Society for Bipolar Disorders Task Force report on pediatric bipolar disorder: Knowledge to date and directions for future research

“…47 There are, however, examples of non-replication. In contrast to US data, a recent Brazilian imaging study did not find white matter microstructure differences between PBD youth, healthy bipolar offspring and healthy controls, 48 and parent report of youth mood symptoms showed much lower discriminative validity than parent report in other countries. 49 However, it is unclear whether this a true international difference or a difference owing to methodologic factors.…”

White matter integrity in schizophrenia and bipolar disorder: Tract- and voxel-based analyses of diffusion data from the Connectom scanner

“…However, a few studies have reported increased white matter FA in bipolar disorder, suggesting increased directional coherence of certain white matter tracts in some patients (Mahon et al, 2009; Versace et al, 2008; Wessa et al, 2009). Some studies reporting normal white matter findings in bipolar disorder have involved younger or unmedicated subjects (Teixeira et al, 2014), and young adult patients often lack the cortical thinning seen in older cohorts (Mamah et al, 2016a), suggesting structural abnormalities progress significantly in some bipolar patients. In addition to the potential role of age, medications likely also influence structural connectivity in bipolar disorder patients.…”

Psychoradiologic abnormalities of white matter in patients with bipolar disorder: diffusion tensor imaging studies using tract-based spatial statistics

“…A total of 165 patients (29.7%) were reported to have comorbidities, which included substance abuse, panic disorder, anxiety disorder, posttraumatic stress disorder, obsessive-compulsive disorder and attention-deficit/ hyperactivity disorder, among others. Of the 18 DTI studies, 2 studies 43,44 involved 36 adolescents with BD.…”

“…Only 5 included studies 34,37,38,43,44 reported white-matter alter ations in patients with BD and psychosis. One study included only BD patients with psychosis, and the other 4 reported only the percentage of patients with psychosis and did no subgroup analysis.…”