Plasma
haloperidol (HPD) concentration,
prolactin (PRL) and
cortisol levels were monitered in eighteen normal adult men before and after
intravenous administration of 2.5 mg
haloperidol for 150 min. in order to elucidate emotional state and autonomic nervous function during state of
akathisia psychophysiologically, power spectrum of photoelectric finger plethysmogram via Fourier transform, skin potential reflex (SPR) and heart rate (HR) before and after the injection were simultaneously examined in all subjects. Power distribution of spectrum of plethysmogram showed normal pattern (main peak power was observed on about 1 Hz and 2nd peak was less than 0.3 Hz.) in all subjects before injection. The spectrum of about 1 Hz was significantly decreased after the injection and that of less than 0.3 Hz tended to be increased in the
akathisia group. There was no significant difference of Plasma PRL and HPD concentration in both
akathisia and non-
akathisia groups. However, significant correlation between these two parameters was found in both groups. The mean plasma
cortisol level of the
akathisia group was tended to be lower than that of the non-
akathisia group. The former group was divided into the following two subgroups by power spectrum analysis; the high frequency dominant group (HF) and the low frequency dominant group (LF). The main peak of the former group was about 1 Hz, and that of the latter group was 0.3 Hz. The mean plasma
cortisol level of LF was significantly lower than that of the non-
akathisia group on 90 min after the injection of HPD. These results suggest that
akathisia could be measured objectively by power spectrum of plethysmogram, and that some
neurotransmitters other than
dopamine also might be related with
akathisia.