Patients with bipolar disorder who had undergone multiple manic episodes had significantly lower regional activation in the prefrontal‐striatal‐amygdala networks than single-episode patients, according to Logan Borgelt of the department of psychiatry and behavioral neuroscience at the University of Cincinnati and associates.
For the study, the investigators collected functional MRI data from 57 first‐episode manic patients (mean age, 19 years; mean Young Mania Rating Scale  score, 26) and 50 multiepisode patients (mean age, 32 years; mean YMRS score, 21) who performed a continuous task with emotional distractions, as well as MR spectroscopy from 52 first-episode patients (mean age, 19 years; mean YMRS score, 26) and 54 multiepisode patients (mean age, 32 years; mean YMRS, 22). The study was published in Bipolar Disorders.
The investigation found that activation of the bilateral ventrolateral prefrontal cortex (P = .0122 for left; P = .0007 for right), anterior cingulate cortex (P less than .0001), orbitofrontal cortex (P = .0133), putamen (P = .0032), caudate (P = .0008), and amygdala (P = .0215) was significantly lower in multiepisode patients than in single-episode patients. Glutamate and N‐acetylaspartate concentration in the anterior cingulate cortex was also lower in multiepisode patients.
The age of multiepisode patients was, in general, not heavily associated with worse activation; only the right putamen (r = 0.30) and right thalamus (r = 0.30) reached a moderate effect size.
“Our findings are consistent with a hypothesized vicious cycle in which progressive atrophic changes in the prefrontal cortex are associated with functional decrements in affective networks, which in turn contribute to both further neuronal loss and clinical observations of accelerating symptomatic recurrence.,” the investigators wrote.
Mr. Borgelt reported no conflicts. Three coauthors reported consulting with, receiving support and honoraria from, or serving on the speaker’s bureaus for numerous sources. The remaining coauthors did not report any conflicts of interest.
SOURCE: Borgelt L et al. Bipolar Disord. 2019 Apr 26. .