Differential Effects of Mental Stress on Plasma Homovanillic Acid in Schizophrenia and Normal Controls

Stress-Induced Dopamine Release in Humans at Risk of Psychosis: a [11C]Raclopride PET Study

“…In schizophrenia, a prototypical psychotic illness, there is clinical evidence of abnormal DA response to pharmacological challenge, metabolic stressor, and psychological stressor. For example, schizophrenic patients have a higher DA response to amphetamine than controls as measured by receptor binding studies (Laruelle et al, 1996;Breier et al, 1997), and do not show the expected decrease in plasma homovanillic acid (HVA, a DA metabolite) in response to a mental stressor (Sumiyoshi et al, 1999). Schizotypal personality disorder patients also show greater amphetamine-induced DA release than controls, though less than that seen in acute schizophrenic patients (Abi-Dargham et al, 2004).…”

Schizophrenia and Plasma Homovanillic Acid in Response to Mental Stress Methodological Considerations

“…Oranje et al (2000) seem to argue that they obtained pHVA data from a "placebo condition" in this way. Based on the result, Oranje et al claimed that the decrease in pHVA levels during the arithmetic task (in control subjects) observed in our previous studies (Sumiyoshi et al 1998(Sumiyoshi et al , 1999 "might have been the result of its endogenous diurnal variation. "…”

“…In our laboratory, we performed an experiment to evaluate the possible effect of the diurnal change in pHVA levels on the results reported in our previous studies (Sumiyoshi et al 1998(Sumiyoshi et al , 1999. Informed consent to participate in this study was obtained from seven normal male volunteers (mean Ϯ SE age ϭ 31.8 Ϯ 1.2 yr) whose pHVA data were previously reported (Sumiyoshi et al 1999).…”

“…We recently studied the effect of mental stress on plasma homovanillic acid (pHVA), a major metabolite of DA, in normal control subjects and patients with schizophrenia (Sumiyoshi et al 1998(Sumiyoshi et al , 1999. In those studies, subjects took a modified version of the Kraepelin arithmetic task (Kuraishi et al 1957) that requires 30 min for completion.…”

“…Plasma HVA levels, immediately before and after the arithmetic test, were compared. The main finding was that mental stress resulting from the arithmetic task produced differential change patterns of pHVA levels in patients with schizophrenia and control subjects; the decrease in pHVA levels during the arithmetic task observed in normal controls was abolished in patients with schizophrenia (Sumiyoshi et al 1998(Sumiyoshi et al , 1999.…”