Understanding the neurobiology of early-onset bipolar disorder with psychosis
Henrique M. Fernandes, Joana Cabral, Mikkel Petersen, Tim J. Van Hartevelt, Anthony C. James, Gustavo Deco & Morten L Kringelbach
Pediatric bipolar disorder (PBD) with psychosis (delusions and/or hallucinations) is currently not well understood in terms of its underlying neurobiology. The diagnosis of PBD is based primarily on taking clinical history, which is considerably more difficult to obtain from children and adolescents than from adults. The clinical diagnosis could potentially benefit from a better understanding of the underlying neurobiology of PBD, and in particular of the early structural changes in connectivity.
In the current study, we examined the changes in structural connectivity and network dynamics between a group of adolescents with PBD and psychosis and a group of healthy controls, having constructed the connectomes using probabilistic tractography and diffusion tensor imaging (DTI). We also investigated the correlations of structural change with several clinical and physiological scores.
We found significant differences in the structural connectivity and nodal efficiency of regions within the so-called ‘default mode’ network, including regions of the medial orbitofrontal cortices, posterior cingulate and medial temporal gyrus. These results also suggest a laterality tendency in the nodal efficiency changes, mainly in areas linked to emotion, visual processing, and word, numbers and face recognition. Further correlation analysis showed that some of those regions, as well as several graph analysis measures, are significantly well correlated with different IQ measures as well as with coding scores.
These results show that the detected changes in the network dynamics are strongly coherent with the well known clinical deficits associated with BPD, mainly in regions involved in brain networks associated with emotional processing and regulation, and cognitive processing. These findings may in time open up new avenues for rebalancing the brain in PBD.