Prefrontal-temporal gray matter deficits in bipolar disorder patients with persecutory delusions.
OBJECTIVE
Although brain structural deficits have been repeatedly associated with bipolar disorder (BD), inconsistency in morphometric results has been a feature of neuroimaging studies. We hypothesize that this discrepancy is related to the heterogeneity of BD, and examine the question of whether or not more homogeneous clinical subgroups display a more coherent pattern of morphometric abnormalities.


METHODS
In a case-control design, we examined differences in gray matter (GM), white matter (WM) and cerebrospinal fluid (CSF) concentration in 42 BD patients and 42 healthy matched controls using optimized voxel-based morphometry (VBM). Subgroup analyses of patients with a lifetime history of psychotic symptoms (BDP, n=30) and patients with mood-incongruent psychotic symptoms in the form of persecutory delusions (BDPD, n=15) were performed to accord with previous genetic findings.


RESULTS
Analysis of the total BD sample was largely inconclusive, but the BDPD patient subgroup displayed a widespread pattern of significant decreases in GM concentration in the dorsolateral prefrontal (DLPFC), temporal and cingulate cortices, and a significant CSF increase in the adjacent outer ventricular sulci. Comparison of BDPD patients versus BD and BDP patients without persecutory delusions revealed a significant GM decrease in the left DLPFC for the former group.


CONCLUSIONS
BDPD show pronounced structural abnormalities of the prefrontal and temporal lobes which are similar to the deficits previously reported for schizophrenia (SCZ). Our findings suggest that stratification based solely on psychotic symptoms is insufficient for the differentiation of BD into biologically meaningful subgroups, but also question the pathophysiological validity of the dichotomy in classification between schizophrenia and BD.
Central Institute of Mental Health, 68159 Mannheim, Germany. heike.tost@zi-mannheim.de
Heike
H
Tost
Matthias
M
Ruf
Christine
C
Schmäl
Thomas G
TG
Schulze
Carolin
C
Knorr
Christian
C
Vollmert
Katja
K
Bösshenz
Gabriele
G
Ende
Andreas
A
Meyer-Lindenberg
Fritz A
FA
Henn
Marcella
M
Rietschel
D000328:Adult; D001714:Bipolar Disorder / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000453:epidemiology*; D016022:Case-Control Studies; D015897:Comorbidity; D003702:Delusions / Q000134:cerebrospinal fluid / Q000175:diagnosis / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000033:anatomy & histology* / Q000473:pathology*; D013702:Temporal Lobe / Q000033:anatomy & histology* / Q000473:pathology*