Do drug treatment variables predict cognitive performance in multidrug-treated opioid-dependent patients? A regression analysis study

Gender disparities in neuropsychological assessment research in drug abuse populations: A systematic review

Objective: To systematically review the literature on the neurocognitive effects of drug use to determine if there are significant gender differences. Methods: In April 2023, we conducted a broad search in MEDLINE (via PubMed), PsycINFO, and Embase for original research studies that used objective neuropsychological assessment to evaluate neurocognition in persons with drug use. Data extraction was performed in a masked, duplicate fashion. Results: Our initial search returned 22,430 records, of which 273 articles were included in our analysis. We found significant underrepresentation of women as participants in the studies. Twenty-one percent of studies had exclusively male participants; when women were included, they averaged only 23% of the sample. Only 49 studies sufficiently documented an analysis of their results by gender; due to the heterogeneity in study characteristics, no conclusions about cognitive differences between women and men could be made. Conclusions: Women are significantly underrepresented in the research on cognition in drug use. Increased efforts to include more women participants and consistent analysis and reporting of data for potential gender differences will be required to close this gap in knowledge, which may lead to improved substance abuse treatment approaches for women.

Improvement in Cognitive Performance after One Year of Methadone Maintenance Treatment

Individuals with substance use disorders are known to suffer from stress, poor sleep, and cognitive impairment. We investigated whether individuals with opioid use disorder would improve cognitive performance following a year of methadone maintenance treatment (MMT). Perceived Stress Scale (PSS), the Pittsburgh Sleep Quality Index (PSQI), and a standardized computerized cognitive battery were administered at admission (T0) to 29 patients, and repeatedly following one year of MMT (T1) by 19 patients. Admission measures did not differ between those who studied once or twice. Patients who perceived very high stress levels (PSS ≥24) at T0 (11, 37.9%) had lower computerized global cognitive scores (67.6±16.2 vs. 90.9±12.5 p≤0.0005). At T1, PSS and PSQI scores improved significantly among 11 patients with no substance abuse, but worsened among 8 with substance abuse (PSS p(interaction)=0.009, p(groups)=0.005, PSQI p(interaction)=0.01, p(groups)=0.04). Global cognitive score improved at T1 for the entire sample (81.8±20.1 to 89.2±13.8, p=0.05). Differentiation by high stress at T0 or by substance abuse at T1 subgroups showed that improvement was observed by those with very low cognitive scores at T0. Patients with poor cognition may improve following one year of MMT, due to stress and substance abuse reduction. Interventions for stress reduction are recommended.

Cognitive effects of labeled addictolytic medications

INTRODUCTION

Alcohol, tobacco, and illegal drug usage is pervasive throughout the world, and abuse of these substances is a major contributor to the global disease burden. Many pharmacotherapies have been developed over the last 50years to target addictive disorders. While the efficacy of these pharmacotherapies is largely recognized, their cognitive impact is less known. However, all substance abuse disorders are known to promote cognitive disorders like executive dysfunction and memory impairment. These impairments are critical for the maintenance of addictive behaviors and impede cognitive behavioral therapies that are regularly administered in association with pharmacotherapies. It is also unknown if addictolytic medications have an impact on preexisting cognitive disorders, and if this impact is modulated by the indication of prescription, i.e. abstinence, reduction or substitution, or by the specific action of the medication.

METHOD

We reviewed the cognitive effects of labeled medications for tobacco addiction (varenicline, bupropion, nicotine patch and nicotine gums), alcohol addiction (naltrexone, nalmefene, baclofen, disulfiram, sodium oxybate, acamprosate), and opioid addiction (methadone, buprenorphine) in human studies. Studies were selected following MOOSE guidelines for systematic reviews of observational studies, using the keywords [Cognition] and [Cognitive disorders] and [treatment] for each medication.

RESULTS

971 articles were screened and 77 studies met the inclusion criteria and were reported in this review (for alcohol abuse, n=21, for tobacco n=22, for opioid n=34. However, very few comparative clinical trials have explored the chronic effects of addictolytic medications on cognition in addictive behaviors, and there are no clinical trials on the cognitive impact of nalmefene in patients suffering from alcohol use disorders.

DISCUSSION

Although some medications seem to enhance cognition in patients suffering from cognitive disorders, others could promote cognitive impairments, and our work highlights a lack of literature on this subject. In conclusion, more comparative clinical trials are needed to better understand the cognitive impact of addictolytic medications.

The Role of Working Memory for Cognitive Control in Anorexia Nervosa versus Substance Use Disorder

Prefrontal cortex executive functions, such as working memory (WM) interact with limbic processes to foster impulse control. Such an interaction is referred to in a growing body of publications by terms such as cognitive control, cognitive inhibition, affect regulation, self-regulation, top-down control, and cognitive–emotion interaction. The rising trend of research into cognitive control of impulsivity, using various related terms reflects the importance of research into impulse control, as failure to employ cognitions optimally may eventually result in mental disorder. Against this background, we take a novel approach using an impulse control spectrum model – where anorexia nervosa (AN) and substance use disorder (SUD) are at opposite extremes – to examine the role of WM for cognitive control. With this aim, we first summarize WM processes in the healthy brain in order to frame a systematic review of the neuropsychological, neural and genetic findings of AN and SUD. In our systematic review of WM/cognitive control, we found n = 15 studies of AN with a total of n = 582 AN and n = 365 HC participants; and n = 93 studies of SUD with n = 9106 SUD and n = 3028 HC participants. In particular, we consider how WM load/capacity may support the neural process of excessive epistemic foraging (cognitive sampling of the environment to test predictions about the world) in AN that reduces distraction from salient stimuli. We also consider the link between WM and cognitive control in people with SUD who are prone to ‘jumping to conclusions’ and reduced epistemic foraging. Finally, in light of our review, we consider WM training as a novel research tool and an adjunct to enhance treatment that improves cognitive control of impulsivity.

Primary care management of opioid use disorders: Abstinence, methadone, or buprenorphine-naloxone?

OBJECTIVE

To advise physicians on which treatment options to recommend for specific patient populations: abstinence-based treatment, buprenorphine-naloxone maintenance, or methadone maintenance.

SOURCES OF INFORMATION

PubMed was searched and literature was reviewed on the effectiveness, safety, and side effect profiles of abstinence-based treatment, buprenorphine-naloxone treatment, and methadone treatment. Both observational and interventional studies were included.

MAIN MESSAGE

Both methadone and buprenorphine-naloxone are substantially more effective than abstinence-based treatment. Methadone has higher treatment retention rates than buprenorphine-naloxone does, while buprenorphine-naloxone has a lower risk of overdose. For all patient groups, physicians should recommend methadone or buprenorphine-naloxone treatment over abstinence-based treatment (level I evidence). Methadone is preferred over buprenorphine-naloxone for patients at higher risk of treatment dropout, such as injection opioid users (level I evidence). Youth and pregnant women who inject opioids should also receive methadone first (level III evidence). If buprenorphine-naloxone is prescribed first, the patient should be promptly switched to methadone if withdrawal symptoms, cravings, or opioid use persist despite an optimal buprenorphine-naloxone dose (level II evidence). Buprenorphine-naloxone is recommended for socially stable prescription oral opioid users, particularly if their work or family commitments make it difficult for them to attend the pharmacy daily, if they have a medical or psychiatric condition requiring regular primary care (level IV evidence), or if their jobs require higher levels of cognitive functioning or psychomotor performance (level III evidence). Buprenorphine-naloxone is also recommended for patients at high risk of methadone toxicity, such as the elderly, those taking high doses of benzodiazepines or other sedating drugs, heavy drinkers, those with a lower level of opioid tolerance, and those at high risk of prolonged QT interval (level III evidence).

CONCLUSION

Individual patient characteristics and preferences should be taken into consideration when choosing a first-line opioid agonist treatment. For patients at high risk of dropout (such as adolescents and socially unstable patients), treatment retention should take precedence over other clinical considerations. For patients with high risk of toxicity (such as patients with heavy alcohol or benzodiazepine use), safety would likely be the first consideration. However, the most important factor to consider is that opioid agonist treatment is far more effective than abstinence-based treatment.

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Objectif

Conseiller les médecins quant aux options thérapeutiques à recommander à des populations précises de patients : approche axée sur l’abstinence, traitement d’entretien par la buprénorphine-naloxone ou traitement d’entretien par la méthadone.

Sources d’information

Une recherche sur PubMed a été effectuée, et on a relevé dans les publications les données sur l’efficacité, l’innocuité et le profil d’effets indésirables de l’approche axée sur l’abstinence, du traitement par la buprénorphine-naloxone et du traitement par la méthadone. Les études d’observation et interventionnelles ont été incluses.

Message principal

La méthadone et la buprénorphine-naloxone sont substantiellement plus efficaces que l’approche axée sur l’abstinence. La méthadone présente un taux de rétention plus élevé que la buprénorphine-naloxone, alors que la buprénorphine-naloxone présente un risque plus faible de surdose. Les médecins devraient recommander le traitement par la méthadone ou la buprénorphine-naloxone plutôt que l’approche axée sur l’abstinence, et ce, à tous les groupes de patients (données de niveau I). La méthadone est préférable à la buprénorphine-naloxone chez les patients qui présentent un risque élevé d’abandon, comme les usagers d’opioïdes par injection (données de niveau I). Les jeunes et les femmes enceintes qui font usage d’opioïdes par injection devraient aussi recevoir la méthadone d’abord (données de niveau III). Si la buprénorphine-naloxone est prescrite en premier, il faut faire passer rapidement le patient à la méthadone si les symptômes de sevrage, les fortes envies ou la consommation d’opioïdes persistent malgré une dose optimale de buprénorphine-naloxone (données de niveau II). La buprénorphine-naloxone est recommandée chez les usagers d’opioïdes sur ordonnance par voie orale socialement stables, surtout s’ils ont un emploi ou si leurs obligations familiales les empêchent de se rendre à la pharmacie tous les jours, s’ils ont une affection médicale ou psychiatrique exigeant des soins réguliers de première ligne (données de niveau IV), ou encore si leur emploi exige une fonction cognitive ou un rendement psychomoteur élevés (données de niveau III). La buprénorphine-naloxone est aussi recommandée chez les patients qui présentent un risque élevé de toxicité à la méthadone, tels que les personnes âgées, les personnes qui prennent de fortes doses de benzodiazépines ou d’autres sédatifs, les gros buveurs, les personnes dont la tolérance aux opioïdes est faible et les personnes à risque de prolongement de l’intervalle QT (données de niveau III).

Conclusion

Il faut tenir compte des caractéristiques et des préférences individuelles des patients lors de la sélection d’un traitement de première intention par un agoniste des opioïdes. Chez les patients qui présentent un risque élevé d’abandon (adolescents et patients socialement instables), la rétention en traitement doit avoir préséance sur les autres considérations cliniques. Chez les patients qui présentent un risque élevé de toxicité (comme les usagers abusifs d’alcool ou de benzodiazépines), la sécurité a sans doute préséance. Ce qu’il importe le plus de considérer toutefois, c’est que le traitement par un agoniste des opioïdes est beaucoup plus efficace que l’approche axée sur l’abstinence.