Differential effects of dopaminergic drugs on anxiety and arousal in healthy volunteers with high and low anxiety.
1. The appearance of frontal midline theta activity (Fm theta), the distinct EEG theta rhythm in the frontal midline area during performance of a mental task, indicates relief from anxiety in humans. 2. The authors examined the effects of bromocriptine and sulpiride on anxiety and arousal in 24 male university students with (Fm theta group, n = 12) and without (non-Fm theta group, n = 12) Fm theta. Subjects were given placebo, 2.5 mg bromocriptine and 100 mg sulpiride in a double-blind crossover design. 3. Blood samples were obtained, STAI scores were determined, and EEGs were recorded before and during the performance of an arithmetic addition task. The test was repeated twice: before and 1 hr after drug administration. 4. Bromocriptine reduced the HVA concentration in both groups; sulpiride caused an increase in both groups. In the Fm theta group, bromocriptine did not alter the appearance time of Fm theta, the state anxiety score or the task performance; sulpiride increased the Fm theta amount and reduced the state anxiety but did not affect the task performance. In the non-Fm theta group, bromocriptine increased the Fm theta duration and reduced the state anxiety score but did not influence the task performance, while sulpiride reduced Fm theta and increased the state anxiety but had no effect on the task performance. 5. These results suggest that the sensitivity of presynaptic D2 receptors is higher in high-anxiety subjects compared with low-anxiety subjects, and that anxiolytic effects in high-anxiety humans and those in low-anxiety humans may be caused by decreased and increased DA activity, respectively. In addition, the stimulation of DA function may cause anxiogenic effects in high-anxiety individuals.
Mizuki
Y
Y
Department of Neuropsychiatry, Yamaguchi University School of Medicine, Japan.
Suetsugi
M
M
Ushijima
I
I
Yamada
M
M
D000328:Adult; D001007:Anxiety / Q000188:drug therapy*; D001143:Arousal / Q000187:drug effects*; D001971:Bromocriptine / Q000494:pharmacology*; D004311:Double-Blind Method; D004569:Electroencephalography / Q000187:drug effects*; D006801:Humans; D008297:Male; D013469:Sulpiride / Q000494:pharmacology*
D001971:Bromocriptine; D013469:Sulpiride