Decision-making ability in current and past users of opiates: A meta-analysis

Effects of medication assisted treatment (MAT) for opioid use disorder on functional outcomes: A systematic review

This systematic review synthesizes evidence on the effects of Medication-Assisted Treatment (MAT) for opioid use disorder (OUD) on functional outcomes, including cognitive (e.g., memory), physical (e.g., fatigue), occupational (e.g., return to work), social/behavioral (e.g., criminal activity), and neurological (e.g., balance) function. Five databases were searched from inception to July 2017 to identify English-language controlled trials, case control studies, and cohort comparisons of one or more groups; cross-sectional studies were excluded. Two independent reviewers screened identified literature, abstracted study-level information, and assessed the quality of included studies. Meta-analyses used the Hartung-Knapp method for random-effects models. The quality of evidence was assessed using the GRADE approach. A comprehensive search followed by 1411 full text publication screenings yielded 30 randomized controlled trials (RCTs) and 10 observational studies meeting inclusion criteria. The studies reported highly diverse functional outcome measures. Only one RCT was rated as high quality, but several methodologically sound observational studies were identified. The statistical power to detect differences in functional outcomes was unclear in most studies. When compared with matched "healthy" controls with no history of substance use disorder (SUD), in two studies MAT patients had significantly poorer working memory and cognitive speed. One study found MAT patients scored worse in aggressive responding than did "healthy" controls. A large observational study found that MAT users had twice the odds of involvement in an injurious traffic accident as non-users. When compared with persons with OUD not on MAT, one cohort study found lower fatigue rates among buprenorphine-treated OUD patients. No differences were reported for occupational outcomes and results for criminal activity and other social/behavioral areas were mixed. There were few differences among MAT drug types. A pooled analysis of three RCTs found a significantly lower prevalence of fatigue with buprenorphine compared to methadone, while a meta-analysis of the same RCTs found no statistical difference in insomnia prevalence. Three RCTs that focused on cognitive function compared the effects of buprenorphine to methadone; no statistically significant differences in memory, cognitive speed and flexibility, attention, or vision were reported. The quality of evidence for most functional outcomes was rated low or very low. In sum, weaknesses in the body of evidence prevent strong conclusions about the effects of MAT for opioid use disorder on functional outcomes. Rigorous studies of functional effects would strengthen the body of literature.

Why Do Those With Long-Term Substance Use Disorders Stop Abusing Substances? A Qualitative Study

Although a significant proportion of adults recover from substance use disorders (SUDs), little is known about how they reach this turning point or why they stop using. The purpose of the study was to explore the factors that influence reasoning and decision making about quitting substance use after a long-term SUD. Semistructured interviews were conducted with 18 participants, each of whom had been diagnosed with a SUD and had been abstinent for at least 5 years. A resource group of peer consultants in long-term recovery from SUDs contributed to the study’s planning, preparation, and initial analyses. Participants recalled harmful consequences and significant events during their years of substance use. Pressure and concern from close family members were important in their initial efforts to abstain from substance use. Being able to imagine a different life, and the awareness of existing treatment options, promoted hope and further reinforced their motivation to quit. Greater focus on why those with SUDs want to quit may help direct treatment matching; treatment completion may be more likely if the person’s reasons for seeking help are addressed.

Decision-making, somatic markers and emotion processing in opiate users

RATIONALE

Opiate use is associated with deficits in decision-making. A possible explanation for these deficits is provided by the somatic marker hypothesis, which suggests that substance users may experience abnormal emotional responses during decision-making involving reward and punishment. This in turn may interfere with the brief physiological arousal, i.e. somatic markers that normally occur in anticipation of risky decisions. To date, the applicability of the somatic marker hypothesis to explain decision-making deficits has not been investigated in opiate users.

OBJECTIVES

This study assessed whether decision-making deficits in opiate users were related to abnormal emotional responses and reduced somatic markers.

METHODS

Opiate users enrolled in an opiate substitute treatment program (n = 28) and healthy controls (n = 32) completed the Iowa Gambling Task (IGT) while their skin conductance responses (SCRs) were recorded. Participants' emotional responses to emotion-eliciting videos were also recorded using SCRs and subjective ratings.

RESULTS

Opiate users displayed poorer decision-making on the IGT than did controls. However, there were no differences between the groups in SCRs; both groups displayed stronger SCRs following punishment than following reward, and both groups displayed stronger anticipatory SCRs prior to disadvantageous decisions than advantageous decisions. There were no group differences in objective or subjective measures of emotional responses to the videos.

CONCLUSIONS

The results suggest that deficits in emotional responsiveness are not apparent in opiate users who are receiving pharmacological treatment. Thus, the somatic marker hypothesis does not provide a good explanation for the decision-making deficits in this group.

Effects of disulfiram on choice behavior in a rodent gambling task: association with catecholamine levels

RATIONALE

Gambling disorder is a growing societal concern, as recognized by its recent classification as an addictive disorder in the DSM-5. Case reports have shown that disulfiram reduces gambling-related behavior in humans.

OBJECTIVES

The purpose of the present study was to determine whether disulfiram affects performance on a rat gambling task, a rodent version of the Iowa gambling task in humans, and whether any changes were associated with alterations in dopamine and/or norepinephrine levels.

METHODS

Rats were administered disulfiram prior to testing on the rat gambling task or prior to analysis of dopamine or norepinephrine levels in brain homogenates. Rats in the behavioral task were divided into two subgroups (optimal vs suboptimal) based on their baseline levels of performance in the rat gambling task. Rats in the optimal group chose the advantageous strategy more, and rats in the suboptimal group (a parallel to problem gambling) chose the disadvantageous strategy more. Rats were not divided into optimal or suboptimal groups prior to neurochemical analysis.

RESULTS

Disulfiram administered 2 h, but not 30 min, before the task dose-dependently improved choice behavior in the rats with an initial disadvantageous "gambling-like" strategy, while having no effect on the rats employing an advantageous strategy. The behavioral effects of disulfiram were associated with increased striatal dopamine and decreased striatal norepinephrine.

CONCLUSIONS

These findings suggest that combined actions on dopamine and norepinephrine may be a useful treatment for gambling disorders.

Remifentanil maintains lower initial delayed nonmatching-to-sample accuracy compared to food pellets in male rhesus monkeys

Emerging human laboratory and preclinical drug self-administration data suggest that a history of contingent abused drug exposure impairs performance in operant discrimination procedures, such as delayed nonmatching-to-sample (DNMTS), that are hypothesized to assess components of executive function. However, these preclinical discrimination studies have exclusively used food as the reinforcer and the effects of drugs as reinforcers in these operant procedures are unknown. The present study determined effects of contingent intravenous remifentanil injections on DNMTS performance hypothesized to assess 1 aspect of executive function, working memory. Daily behavioral sessions consisted of 2 components with sequential intravenous remifentanil (0, 0.01-1.0 μg/kg/injection) or food (0, 1-10 pellets) availability in nonopioid dependent male rhesus monkeys (n = 3). Remifentanil functioned as a reinforcer in the DNMTS procedure. Similar delay-dependent DNMTS accuracy was observed under both remifentanil- and food-maintained components, such that higher accuracies were maintained at shorter (0.1-1.0 s) delays and lower accuracies approaching chance performance were maintained at longer (10-32 s) delays. Remifentanil maintained significantly lower initial DNMTS accuracy compared to food. Reinforcer magnitude was not an important determinant of DNMTS accuracy for either remifentanil or food. These results extend the range of experimental procedures under which drugs function as reinforcers. Furthermore, the selective remifentanil-induced decrease in initial DNMTS accuracy is consistent with a selective impairment of attentional, but not memorial, processes. (PsycINFO Database Record

Established risk factors for addiction fail to discriminate between healthy gamers and gamers endorsing DSM-5 Internet gaming disorder

Background and aims The DSM-5 includes criteria for diagnosing Internet gaming disorder (IGD) that are adapted from substance abuse and widely used in research and clinical contexts, although evidence supporting their validity remains scarce. This study compared online gamers who do or do not endorse IGD criteria regarding self-control-related abilities (impulsivity, inhibitory control, and decision-making), considered the hallmarks of addictive behaviors. Method A double approach was adopted to distinguish pathological from recreational gamers: The first is the classic DSM-5 approach (≥5 criteria required to endorse the IGD diagnosis), and the second consists in using latent class analysis (LCA) for IGD criteria to distinguish gamers' subgroups. We computed comparisons separately for each approach. Ninety-seven volunteer gamers from the community were recruited. Self-reported questionnaires were used to measure demographic- and game-related characteristics, problematic online gaming (with the Problematic Online Gaming Questionnaire), impulsivity (with the UPPS-P Impulsive Behavior Scale), and depression (with the Beck Depression Inventory-II). Experimental tasks were used to measure inhibitory control (Hybrid-Stop Task) and decision-making abilities (Game of Dice Task). Results Thirty-two participants met IGD criteria (33% of the sample), whereas LCA identified two groups of gamers [pathological (35%) and recreational]. Comparisons that used both approaches (DSM-5 and LCA) failed to identify significant differences regarding all constructs except for variables related to actual or problematic gaming behaviors. Discussion The validity of IGD criteria is questioned, mostly with respect to their relevance in distinguishing high engagement from pathological involvement in video games.

Research with Older Adult Methadone Clients: The Importance of Monitoring Suicide Ideation

This study reports on the importance of monitoring suicide ideation among older adult research participants. A recently completed randomized controlled trial of older adults who are current clients in methadone maintenance treatment (MMT) served as a case study to elucidate a suicide protocol that was designed to account for the potential instances of suicide ideation within the research project structure. As the numbers of older adult heroin users increases, this study's findings seek to influence research protocols that involve older adults with addictions who may be particularly vulnerable to suicide risk due to comorbid psychiatric conditions and psychosocial adversities.