Ta. Ketter et al., Baseline cerebral hypermetabolism associated with carbamazepine response, and hypometabolism with nimodipine response in mood disorders, BIOL PSYCHI, 46(10), 1999, pp. 1364-1374
Background: Positron emission tomography (PET) studies have reported baseli
ne (medication free) differences between mood disorder patients and healthy
control subjects, but relatively little is known about relationships betwe
en baseline PET scans and treatment responses. Carbamazepine (CBZ) and to a
more limited extent nimodipine (NIMO) seem useful in mood disorders. We ex
plored whether baseline regional cerebral glucose metabolism (rCMRglu) coul
d discriminate CBZ and NIMO responders from nonresponders and healthy contr
ol subjects.
Methods: In refractory mood disorder patients, we examined relationships be
tween responses to these drugs, assessed by Clinical Global Impression-Impr
ovement scores, and baseline rCMRglu, determined with fluorine-18 deoxygluc
ose and PET.
Results: CBZ responders had baseline left insular hypermetabolism compared
to healthy control subjects and nonresponders, whereas nonresponders had wi
despread (including left insular) hypometabolism. Degree of CBZ response co
rrelated with baseline paralimbic (including insula) and prefrontal hyperme
tabolism, In responders but not nonresponders, CBZ decreased widespread met
abolism, with the degree of decrease in left insula correlating with respon
se. In contrast, NIMO responders but not nonresponders had baseline widespr
ead (including left insular) hypometabolism, Left prefrontal and left insul
ar baseline hypometabolism but not metabolic changes with treatment correla
ted with degree of NIMO response.
Conclusions: These data suggest that baseline anterior paralimbic and prefr
ontal hypermetabolism may be associated with CBZ response, and hypometaboli
sm with NIMO response. Based an these preliminary data, further exploration
of relationships between baseline PET scans and treatment responses is ind
icated.