Mood disturbances in methamphetamine (MA) abusers likely influence drug
use, but the neurobiological bases for these problems are poorly understood.
To assess regional brain function and its possible relationships with
negative affect in newly abstinent MA abusers.
Two groups were compared by measures of mood and cerebral glucose metabolism
([18F]fluorodeoxyglucose positron emission tomography) during performance
of a vigilance task.
Participants were recruited from the general community to a research
Seventeen abstaining (4-7 days) MA abusers (6 women) were compared with
18 control subjects (8 women).
Main Outcome Measures
Self-reports of depressive symptoms and anxiety were measured, as were
global and relative glucose metabolism in the orbitofrontal, cingulate, lateral
prefrontal, and insular cortices and the amygdala, striatum, and cerebellum.
Abusers of MA provided higher self-ratings of depression and anxiety
than control subjects and differed significantly in relative regional glucose
metabolism: lower in the anterior cingulate and insula and higher in the lateral
orbitofrontal area, middle and posterior cingulate, amygdala, ventral striatum,
and cerebellum. In MA abusers, self-reports of depressive symptoms covaried
positively with relative glucose metabolism in limbic regions (eg, perigenual
anterior cingulate gyrus and amygdala) and ratings of state and trait anxiety
covaried negatively with relative activity in the anterior cingulate cortex
and left insula. Trait anxiety also covaried negatively with relative activity
in the orbitofrontal cortex and positively with amygdala activity.
Abusers of MA have abnormalities in brain regions implicated in mood
disorders. Relationships between relative glucose metabolism in limbic and
paralimbic regions and self-reports of depression and anxiety in MA abusers
suggest that these regions are involved in affective dysregulation and may
be an important target of intervention for MA dependence.