A STUDY OF THE POTENTIAL CONFOUNDING EFFECTS OF DIET, CAFFEINE, NICOTINE AND LORAZEPAM ON THE STABILITY OF PLASMA AND URINARY HOMOVANILLIC-ACID LEVELS IN PATIENTS WITH SCHIZOPHRENIA
Cl. Donnelly et al., A STUDY OF THE POTENTIAL CONFOUNDING EFFECTS OF DIET, CAFFEINE, NICOTINE AND LORAZEPAM ON THE STABILITY OF PLASMA AND URINARY HOMOVANILLIC-ACID LEVELS IN PATIENTS WITH SCHIZOPHRENIA, Biological psychiatry, 40(12), 1996, pp. 1218-1221
Ten men inpatients who met DSM-III-R criteria for schizophrenia partic
ipated. On five occasions at least one week apart, each subject had an
intravenous line placed at 0730 after an overnight fast. On each occa
sion blood samples were drawn at 0800 and hourly thereafter through 12
00 noon far measurement of plasma homovanillic acid (HVA). Total four-
hour urine collections were obtained for measurement of urinary HVA. S
ubjects received five experimental conditions, in randomized sequence:
no intervention, smoking one cigarette per hour drinking one caffeina
ted cola per hour, lorazepam 2 mg IV push, or a high monoamine meal. B
aseline (0800) plasma HVA measures showed only minor intrinsic variabi
lity. The average standard deviation in baseline plasma HVA over five
occasions of measurement was low relative to the changes in HVA produc
ed during treatment with antipsychotic medications. The high monoamine
meal significantly elevated plasma HVA, with a similar trend for urin
ary HVA. Neither caffeine, nicotine, nor lorazepam significantly affec
ted plasma or urinary HVA. (C) 1996 Society of Biological Psychiatry