Response inhibition and psychomotor speed during methadone maintenance: impact of treatment duration, dose, and sleep deprivation

Abstract

Background In opiate-dependent individuals, abstinence results in deficits in cognitive functioning, which may be exacerbated by medication-associated sleep disruption. Method To assess cognitive function and the influence of sleep deprivation (SD), 14 healthy control (HC) and 22 methadone maintained (MM) participants completed the Continuous Performance Task (CPT) after a baseline night, a night of total SD, and two recovery sleep nights. The Digit Symbol Substitution Task (DSST) was administered at bedtime and in the morning. Secondary analyses separated MM participants into short- (<12 months; n=8) and long-term (≥12 months; n=14) treatment duration groups, and into low- (< 80 mg; n=9) and high-dose (≥ 80 mg; n=13) groups. Results Linear mixed model ANOVAs revealed that there was no effect of SD. Across all days MM participants had more errors of omission, fewer correct responses, and slower reaction times (RTs) on the CPT, and fewer accurate substitutions on the evening and morning DSST. Short-term MM participants exhibited slower RTs on the CPT, and fewer correct substitutions on the evening DSST compared to long-term MM participants. Low-dose MM participants had slower RTs on the CPT than HCs and high-dose MM participants. Conclusion These data demonstrate that methadone-maintained individuals exhibit poorer performance on tasks of psychomotor speed and selective attention/impulsivity, but with longer-term treatment, performance appears to return toward control levels. Furthermore, while one day of SD was enough to alter subjective reports of sleep quality, cognitive function may be more resilient.

Cognitive performance in methadone maintenance patients: Effects of time relative to dosing and maintenance dose level.

“…Longer methadone treatment duration was associated with better performance on some measures (Sternberg working memory, free recall, and metamemory), though false alarm rates during recognition memory were increased. These findings are consistent with past correlational and longitudinal studies showing improved cognitive performance with methadone stabilization (Bracken, et al, 2012; Gruber et al, 2006; Soyka et al, 2008; Soyka, Zingg, Koller, & Hennig-Fast, 2010). In a longitudinal study, Gruber et al (2006) found improved memory and focused attention (DSST), but no change on measures of semantic fluency, psychomotor function (Trail Making Test), or inhibitory control, following two months of treatment compared to the first few weeks of treatment.…”

Inferior Frontal Cortex Modulation with an Acute Dose of Heroin During Cognitive Control

“…Furthermore, the right IFG is activated not only during response inhibition but also during stimulus-driven attention allocation (Chikazoe et al , 2009). It has been shown that heroin abuse is also associated with deficits in attentional set-shifting (Ornstein et al , 2000) and that opiate-dependent participants actively enrolled in a methadone-maintaining program showed reduced selective attention (Bracken et al , 2012). A recent study explored the cognitive deficits in heroin abusers and showed that the decreased ability to shift attention and inhibit inappropriate response tendencies, which cumulate with years of consumption, may be mediated by dysfunctional IFG activity (Lundqvist, 2010).…”

Pattern of QTc prolongation in Methadone Maintenance Therapy (MMT) subjects receiving different methadone dosages: A prospective cohort study

“…The patients were dichotomized into those receiving methadone more than 80 mg or less than 80 mg. The 80 mg cut-off was chosen since this is the consensus for high dose and low dose methadone grouping as proposed by previous studies 15 - 17 and our predetermined cut-off using Receiver Operating Curve (ROC) analysis 18 . All ECGs were performed 24 hours after last methadone dose with subjects remained supine for 5 minutes prior to ECG recording.…”