Address for correspondence: Kunio Yui, M.D., Department of Psychiatry, Jichi Medical School, Minamikawachi 3311-1, Tochigi 329-0498, Japan. Voice: +81 (48) 862-7520; fax: +81 (48) 836-1372.
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Ann. N.Y. Acad. Sci. 965: 292-304 (2002).
The relation between increased sensitivity to stress associated
with noradrenergic hyperactivity and dopaminergic changes, and
susceptibility to subsequent spontaneous recurrences of methamphetamine
(MAP) psychosis (flashbacks) was examined. Plasma monoamine
metabolite levels were assayed in 19 flashbackers, of whom 10
experienced a single flashback and 9 exhibited subsequent flashbacks,
18 nonflashbackers with a history of MAP psychosis, 9 subjects
with persistent MAP psychosis, and 22 MAP user and 10 nonuser
controls. All flashbackers had undergone frightening stressful
experiences during previous MAP use. They exhibited flashbacks
in response to mild psychosocial stressors. There was no significant
difference in the number of stressful experiences and having
mild psychosocial stressors between the two flashbacker subgroups.
Plasma norepinephrine (NE) levels increased with a small increase
in plasma levels of 3-methoxytyramine (3-MT), an index of dopamine
release, during flashbacks in the 19 flashbackers. Of the 19
flashbackers, the 9 with subsequent episodes had markedly increased
NE levels and slightly increased 3-MT levels during flashbacks,
while the 10 with a single episode displayed small increases
in NE and 3-MT levels during flashbacks. The 9 flashbackers
with subsequent episodes had a longer duration of imprisonment
than the 10 flashbackers with a single episode. Thus, robust
noradrenergic hyperactivity with slightly increased DA release
in response to mild stress may predict subsequent flashbacks.
Long-term exposure to distressing situations appears to contribute
to susceptibility to subsequent flashbacks.
