The functional neuroanatomy of geriatric depression.
OBJECTIVE
Positron Emission Tomography (PET) studies of cerebral glucose metabolism have demonstrated sensitivity in evaluating the functional neuroanatomy of treatment response variability in depression, as well as in the early detection of functional changes associated with incipient cognitive decline. The evaluation of cerebral glucose metabolism in late life depression may have implications for understanding treatment response variability, as well as evaluating the neurobiological basis of depression in late life as a risk factor for dementia.


METHODS
Sixteen patients with geriatric depression and 13 comparison subjects underwent resting PET studies of cerebral glucose metabolism, as well as magnetic resonance (MR) imaging scans to evaluate brain structure.


RESULTS
Cerebral glucose metabolism was elevated in geriatric depressed patients relative to comparison subjects in anterior (right and left superior frontal gyrus) and posterior (precuneus, inferior parietal lobule) cortical regions. Cerebral atrophy (increased cerebrospinal fluid [CSF] and decreased grey and white matter volumes) were observed in some of these regions, as well. Regional cerebral metabolism was positively correlated with severity of depression and anxiety symptoms.


CONCLUSIONS
In contrast to decreased metabolism observed in normal aging and neurodegenerative conditions such as Alzheimer's disease, cortical glucose metabolism was increased in geriatric depressed patients relative to demographically matched controls, particularly in brain regions in which cerebral atrophy was observed, which may represent a compensatory response.
Smith
Gwenn S
GS
Department of Psychiatry Research, The Zucker Hillside Hospital, Glen Oaks, New York, USA. gsmith95@jhmi.edu
Kramer
Elisse
E
Ma
Yilong
Y
Kingsley
Peter
P
Dhawan
Vijay
V
Chaly
Thomas
T
Eidelberg
David
D
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D016022:Case-Control Studies; D003866:Depressive Disorder / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals
D001786:Blood Glucose; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18