Increasing evidence indicates that substance-dependent individuals
(SDI) are impaired in executive control tasks relying on different systems
within the prefrontal cortex (PFC). Three different functional systems
have been described: the dorsolateral prefrontal cortex (DLPC),
orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC) circuits.
Dysfunction within each PFC system is associated with different
behavioral, cognitive, and emotional abnormalities. Few studies have
conducted an exhaustive examination of all these different factors in SDI.
In this study, SDI (including alcohol, cocaine, and methamphetamine
polysubstance users, n = 35) were compared with healthy controls
(n = 36) on a series of behavioral (Frontal Systems Behaviour
Scale, FrSBe), cognitive (N-back, Go-No Go, and Wisconsin Card Sorting
Tasks), and emotional (International Affective Picture System, IAPS)
tasks, each of which was thought to tax a different component of these PFC
functional systems. SDI showed greater behavioral problems in the apathy,
disinhibition, and executive dysfunction subscales of the FrSBe.
Behavioral deficits were significantly associated with several real-life
domains in which SDI typically have problems. SDI also showed poorer
performance on cognitive tests of working memory, response inhibition and
mental flexibility, and abnormal processing of affective images from the
IAPS. Cognitive, behavioral, and emotional measures were moderately
correlated.This study was conducted in the
Department of Neurology, University of Iowa, Iowa City, USA
(JINS, 2006, 12, 405–415.)