ANXIOLYTIC EFFECTS OF LOW-DOSE CLOMIPRAMINE IN HIGHLY ANXIOUS HEALTHY-VOLUNTEERS ASSESSED BY FRONTAL MIDLINE THETA-ACTIVITY

1. The appearance of Fm theta, the distinct EEG theta rhythm in the fr ontal midline area during performance of a mental task, reflects relie f from anxiety in humans. 2. In the present study, the anxiolytic effe cts of low-dose clomipramine were examined by monitoring the Fm theta amount, the STAI scores and the plasma 5-HIAA concentration in 24 male university students with (Fm theta group, n=12) and without (non-Fm t heta group, n=12) Fm theta. 3. Subjects were given placebo, 10 mg and 30 mg clomipramine in a double-blind crossover design. Blood samples w ere obtained, STAI scores were determined, and EEGs were recorded befo re and during the performance of an arithmetic addition task. The test was repeated twice: before and 3 hrs after drug administration. 4. In the non-Fm theta group, 10 mg clomipramine decreased the 5-HIAA conce ntration and state anxiety scores but increased the Fm theta amount, w hile 30 mg clomipramine slightly increased only the Fm theta amount. H owever, there were no differences in these items before and after clom ipramine administration in the Fm theta group. 5. These results sugges t that low doses of clomipramine such as 10 mg may exert anxiolytic ef fects during the acute phase of treatment in highly anxious humans.