Anxiolytic effects of small doses of clomipramine in normal humans.

The appearance of Fm theta, the distinct EEG theta rhythm in the frontal midline area during performance of a mental task, reflects relief from anxiety in humans. In the present study, the anxiolytic effects of small doses of clomipramine were examined by monitoring the Fm theta amount, the STAI-I score and the plasma 5-HIAA concentration in male university students with (Fm theta group, n=12) and without (non-Fm theta group, n=12) Fm theta. The subjects were given placebo, 10 mg and 30 mg clomipramine in a double-blind crossover design. The test was repeated twice: before and 3 hrs after the drug administration. In the non-Fm theta group, 10 mg clomipramine decreased the 5-HIAA concentration and state anxiety scores but increased the Fm theta amount, while 30 mg clomipramine slightly increased only the Fm theta amount. However, there were no differences in these items before and after clomipramine administration in the Fm theta group. These findings suggest that small doses of clomipramine such as 10 mg may exert anxiolytic effects during acute phase of treatmet in highly anxious humans.