Decreased density of GABA-A receptors in the left sensorimotor cortex in akinetic catatonia: investigation of in vivo benzodiazepine receptor binding

Objectives-Catatonia is a psychomotor syndrome with concomittant akinesia a nd anxiety which both respond almost immediately to benzodiazepines such as lorazepam. The benzodiazepine receptor distribution was therefore investig ated in akinetic catatonia with single photon emission tomography (SPECT) u sing iodine-123-iomazenil ((123) I Iomazenil). Methods-Ten akinetic catatonic patients, 10 psychiatric controls (similar a ge, sex, medication, and underlying psychiatric diagnosis but without catat onic syndrome), and 20 healthy controls were investigated with SPECT 2 hour s after injection of (123) I Iomazenil. To exclude potential effects of cer ebral perfusion (r-CBF) r-CBF was additionally investigated with Tc-99mECD SPECT. Results-Catatonic patients showed significantly lower iomazenil binding and altered right-left relations in the left sensorimotor cortex compared with psychiatric (p < 0.001) and healthy (p < 0.001) controls. In addition, the re was significantly lower r-CBF in the right lower prefrontal and parietal cortex in catatonia whereas in the left sensorimotor cortex no differences in r-CBF between groups were found. Catatonic motor and affective symptoms showed significant correlations (p < 0.05) with benzodiazepine binding in the left sensorimotor cortex as well as with right parietal r-CBF. Conclusions-Reduced iomazenil binding suggests decreased density of GABA-A receptors in the left sensorimotor cortex in akinetic catatonia. In additio n to reduced GABA-A receptor density in the left sensorimotor cortex the pa rietal cortex seems to be involved in pathophysiology of catatonic symptoms , it is concluded that, considering results from correlation analyses, both emotional and motor symptoms in catatonia seem to be closely related to le ft sensorimotor and right parietal alterations.