Lorazepam modulates orbitofrontal signal changes during emotional processing in catatonia

Objective: Catatonia is a psychomotor syndrome characterized by concomitant emotional, behavioural and motor symptoms. In many cases clinical symptoms disappear almost immediately with administration of lorazepam, which acts on GABA_A receptors. Methods: Using functional magnetic resonance imaging (fMRI) we investigated prefrontal activation patterns during emotion processing in catatonic patients with and without lorazepam in a double-blind study design. For emotional stimulation the International Affective Picture System (IAPS) was used. BOLD-signals were determined using regions of interest (ROI) and were statistically compared between groups. Results: For negative emotional pictures lorazepam induced higher signal decreases in the orbitofrontal cortex (OFC) in catatonic patients than in healthy subjects resulting in a regularization of activity patterns comparable to healthy subjects with placebo. Conclusions: Results indicate disturbances in the functioning of OFC in catatonia. GABAergic modified emotion regulation with decreased inhibition of affective stimuli could lead to the intense emotions reported by many catatonic patients.