Cognitive impairment among methadone maintenance patients

Comparing attention, impulsivity, and executive functions between patients with opiate use disorder: Buprenorphine maintenance treatment versus active users, in comparison with healthy controls

Background

Opioid use disorders (OUDs) affect over 16 million people worldwide, with a particularly high prevalence rate in Asia. OUDs are associated with significant health consequences, including neurocognitive impairment, which affects individuals' ability to make decisions, respond to stressful situations, and regulate behavior. Understanding the specific ways in which OUDs affect cognitive functioning is important in treatment considerations.

Methods

This study compared the attention, impulsivity, and executive functions of Turkish men with active OUD (n = 40) with those of men in remission from OUD who were on buprenorphine/naloxone maintenance (BMT; n = 41) and with those of a comparison group of healthy controls (HC; n = 43). The Cambridge Neuropsychological Test Automated Battery (CANTAB) was used to assess neurocognitive functioning.

Results

Analyses found significant impairment in measures of continuous attention, cognitive impulsivity, motor impulsivity, and executive functions in the two patient groups compared to the control group, but the two patient groups did not differ from each other.

Conclusion

The data from this study indicate that individuals with OUD exhibit neurocognitive damage, and those in remission from OUD who receive maintenance treatment do not show improvement in this domain. Neurocognitive damages should be considered in long-term treatment planning of patients with OUD.

Harmful effects of opioid use in pregnancy: A scientific review commissioned by the European Board and College of obstetrics and gynaecology (EBCOG)

Caring for pregnant women who have a recreational opioid use disorder is a common clinical challenge in modern obstetric care. These are an elusive population who often have multiple social issues that complicate their pregnancy management. Comprehensive and supportive maternal care can motivate these mothers to change her lifestyle. Multidisciplinary non-judgemental approach with appropriate medication and management, can result in good pregnancy outcomes for mother and her baby.

An fMRI analysis of verbal and non-verbal working memory in people with a past history of opioid dependence

Introduction

Working memory describes the ability to maintain and manipulate information held in mind, and it is a fundamental aspect of executive function. Within drug addiction, impairments of executive control over behavior are thought to lead to poor decision making and risky behaviors. Previous research has demonstrated working memory (WM) and executive function difficulties in opioid-dependent individuals, but the neural underpinnings of such impairments in this population are not well understood.

Methods

This study used functional magnetic resonance imaging to examine the neural mechanisms involved in WM in 13 opioid-dependent, methadone-maintained participants (OP) and 13 matched, healthy controls (HC). A Sternberg item-recognition task was administered with three conditions: (1) a "verbal" condition in which participants determined whether any six visually presented target letters matched a probe item that was presented 4-6 s later, (2) a "non-verbal" condition in which participants were presented with a Chinese character and, following a 4-6 s delay, determined whether the character matched the probe item, and (3) a "control" condition in which participants were presented with three horizontal lines and following the same delay, determined whether the lines matched a probe item (always the same three lines). Functional magnetic resonance imaging (fMRI) contrasts focused on the delay (or "maintenance") phase for verbal and non-verbal conditions relative to the control condition.

Results

Accuracy on the WM task did not differ between groups, but the OP group was significantly slower to respond. The fMRI imaging results indicated differences in brain activity between the OP and HC groups. fMRI-guided regions of interest correlated with age of first alcohol and THC use, suggesting that early substance use, in addition to years of opioid-abuse, may have played a role in the OP group's WM performance.

Discussion

A deeper understanding of these neural differences between opioid-dependent individuals and their healthy control counterparts helps shed light on fundamental ways in which substance use impacts the brain and cognition, potentially opening up novel avenues for therapeutic targets to treat substance use disorder.

Latent profile analysis of data from the brief inventory of neurocognitive impairment (BINI) to develop neuro-cognitive profiles among opioid-dependent patients in drug treatment

BACKGROUND

Neurocognitive dysfunction is common among individuals with opioid use disorders (OUD) and can impede a range of treatment outcomes. We developed the 57-item Brief Inventory of Neuro-cognitive Impairment (BINI) to help detect and monitor neurocognitive dysfunction in the context of drug treatment settings. To date, no study has examined the possible presence of BINI subgroups among OUD patients, which could enhance our ability to tailor intervention strategies to meet individual treatment needs. The purpose of this study was to conduct a latent profile analysis to identify BINI subgroups that differ in terms of their reported and objective neurocognitive dysfunction. We hypothesized that subgroups would emerge, suggesting the potential benefit of implementing tailored strategies for optimal treatment outcomes.

METHODS

Latent profile analyses included data from opioid-dependent patients (N = 177) enrolled in a methadone maintenance treatment program between July 2018 and October 2019.

RESULTS

We found three profiles of self-reported neurocognitive symptoms, including those with 1) minimal concerns 2) moderate concerns, and 3) many concerns across multiple domains.

CONCLUSIONS

If these results are confirmed, the BINI may be used to rapidly identify persons who require specific accommodation strategies to improve their drug treatment outcomes.

Prospective Memory, Sustained Attention and Response Inhibition in Poly-Substance Users Stable on Methadone Maintenance Treatment

Background: Prospective memory and response inhibition are interrelated constructs, though studied separately in the drug addiction literature. Also, although sustained attention underlies response inhibition, its role in the relation between these functions has been largely neglected. The limited research on the cognitive effects of methadone-maintenance treatment (MMT) further stresses the importance of investigating these effects. Objective: Therefore, the current study focused on possible effects of MMT combined with long-term drug abuse on all these functions. Thirty five long term opiate/poly-substance users in MMT and thirty four drug-free controls were screened for socioeconomic status, anxiety, depression and general, non-verbal intelligence and then tested on a self-report measure of prospective memory and on the Go/No-Go task. Results: Compared to controls, the MMT group scored worse in all functions assessed. Prospective memory scores were also negatively related to Go/NoGo accuracy scores. Conclusion: As predicted, (a) the MMT participants show impairments in prospective memory, sustained attention and response inhibition and (b) prospective memory, response inhibition and sustained attention are related constructs. The results of this study could inform current rehabilitation and relapse prevention cognitive training practices.

Chronic exposure to methadone impairs memory, induces microgliosis, astrogliosis and neuroinflammation in the hippocampus of adult male rats

Methadone is a centrally-acting synthetic opioid analgesic widely used in methadone maintenance therapy (MMT) programs throughout the world. Given its neurotoxic effects, particularly on the hippocampus, this study aims to address the behavioral and histological alterations in the hippocampus associated with methadone administration. To do so, twenty-four adult male albino rats were randomized into two groups, methadone treatment and control. Methadone was administered subcutaneously (2.5-10 mg/kg) once a day for two consecutive weeks. A comparison was drawn with behavioral and structural changes recorded in the control group. The results showed that methadone administration interrupted spatial learning and memory function. Accordingly, treating rats with methadone not only induced cell death but also prompted the actuation of microgliosis, astrogliosis, and apoptotic biomarkers. Furthermore, the results demonstrated that treating rats with methadone decreased the complexity of astrocyte processes and the complexity of microglia processes. These findings suggest that methadone altered the special distribution of neurons. Also, a substantial increase was observed in the expression of TNF-α due to methadone. According to the findings, methadone administration exerts a neurodegenerative effect on the hippocampus via dysregulation of microgliosis, astrogliosis, apoptosis, and neuro-inflammation.

The association between medication for opioid use disorder and employment outcomes in the U.S.: The relevance of race and ethnicity

•White admissions given MOUD were less likely to become unemployed at discharge.•Blacks and Hispanics given MOUD were more likely to remain unemployed at discharge.•Racial disparities associated with MOUD have notable implications for policy.

Effects of unhealthy alcohol use on brain morphometry and neurocognitive function among people with HIV

Individual impacts of alcohol misuse and HIV on brain structure and function have been well demonstrated; however, the potential compounded effect of these conditions is seldom considered, despite the high prevalence of alcohol use in HIV infection. We aimed to determine the effects of unhealthy alcohol use on brain morphometry and cognitive function amongst people with HIV (PWH). In 27 (50.9%) HIV-positive users of alcohol and 26 (49.1%) HIV-positive abstainers from alcohol, results revealed significant differences for left and right amygdala (p < 0.01), left and right hippocampus (p = 0.05), left and right posterior cingulate (p < 0.01), left and right precuneus (p < 0.01), left insula (p < 0.01), left and right caudate (p < 0.01), right thalamus (p < 0.01), and corpus callosum (p < 0.05). Mean volume of these regions was significantly smaller in HIV-positive alcohol users compared to HIV-positive abstainers. Homogeneity of slopes ANCOVA revealed significant associations between anterior cingulate cortex, precuneus, amygdala, hippocampus, and insula volumes and cognitive function in the domains of learning and delayed recall, motor function, speed of information processing, executive function, attention/working memory, and language. Among PWH, unhealthy alcohol use is associated with negative effects on brain structure and cognitive function.

Underrepresentation of diverse populations and clinical characterization in opioid agonist treatment research: A systematic review of the neurocognitive effects of buprenorphine and methadone treatment

INTRODUCTION

The relative neurocognitive effects of the two most common opioid agonist treatments (OAT; buprenorphine and methadone) for opioid use disorder (OUD) are poorly understood. The aim of this systematic review is to examine the neurocognitive effects of OAT (buprenorphine and methadone) and the clinical and sociodemographic characteristics of study samples.

METHODS

The research team queried PubMed, PsycINFO and Cochrane Reviews for articles (01/1980-01/2020) with terms related to neurocognitive testing in adults (age ≥ 18) prescribed OAT. The team extracted neurocognitive data and grouped them by domain (e.g., executive functioning, learning/memory), and assessed study quality.

RESULTS

The search retrieved 2341 abstracts, the team reviewed 278 full articles, and 32 met inclusion criteria. Of these, 31 were observational designs and one was an experimental design. Healthy controls performed better across neurocognitive domains than OAT-treated persons (buprenorphine or methadone). Compared to those with active OUD, OAT-treated persons had better neurocognition in various domains. However, in seven studies comparing buprenorphine- and methadone-treated persons, buprenorphine was associated with better neurocognition than was methadone, with moderate to large effect sizes in executive functioning, attention/working memory, and learning/memory. Additionally, OAT research underreports clinical characteristics and underrepresents Black and Latinx adults, as well as women.

CONCLUSIONS

Findings suggest that compared to active opioid use, both buprenorphine and methadone treatment are associated with better neurocognitive functioning, but buprenorphine is associated with better executive functioning, attention/working memory, and learning/memory. These findings should be interpreted with caution given widespread methodological heterogeneity, and limited representation of ethnoracially diverse adults and women. Rigorous longitudinal comparisons with more diverse, better characterized samples will help to inform treatment and policy recommendations for persons with OUD.

Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

BACKGROUND

Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans.

METHODS

PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized.

RESULTS

Seventy-nine journal articles, published between 1973-2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, as well as engagement in treatment of substance use disorders.

CONCLUSIONS

Respiratory depression is a defining characteristic of opioid overdose and prolonged cerebral hypoxia may cause brain injuries and/or neurocognitive impairments. The onset, characteristics, and duration of such injuries is variable and additional research is needed to understand their clinical implications.

Risk of motor vehicle collisions after methadone use

Methadone maintenance treatment (MMT) can alleviate opioid dependence. However, MMT possibly increases the risk of motor vehicle collisions. The current study investigated preliminary estimation of motor vehicle collision incidence rates. Furthermore, in this population-based retrospective cohort study with frequency-matched controls, opiate adults receiving MMT (cases) and those not receiving MMT (controls) were identified at a 1:2 ratio by linking data from several nationwide administrative registry databases. From 2009 to 2016, the crude incidence rate of motor vehicle collisions was the lowest in the general adult population, followed by that in opiate adults, and it was the highest in adults receiving MMT. The incidence rates of motor vehicle collisions were significantly higher in opiate users receiving MMT than in those not receiving MMT. Kaplan–Meier curves of the incidence of motor vehicle collisions differed significantly between groups, with a significant increased risk during the first 90 days of follow-up. In conclusion, drivers receiving MMT have higher motor vehicle collision risk than those not receiving MMT in opiate users, and it is worthy of noticing road safety in such drivers, particularly during the first 90 days of MMT.

In 2019, 58 million people were estimated to use opioids – a group of substances that include drugs like heroin and morphine. Dependence on opioids can be managed using a prescribed dose of an opioid called methadone, which is administered through a controlled treatment plan. This so-called methadone maintenance treatment manages withdrawal symptoms in opioid-dependent individuals and can reduce the occurrences of overdose, criminal activity and transmission of diseases such as HIV.

However, methadone acts on the same brain receptors as other opioids, and individuals receiving methadone may experience impaired motoric and cognitive functioning, including reduced driving ability. It is therefore important to know whether methadone maintenance treatment may increase an individual’s risk to cause road accidents.

To assess motor vehicle collision risk associated with individuals receiving methadone maintenance treatment, Yang et al. analysed data from the Taiwan National Health Insurance Research Database and six Taiwanese administrative registries, including the ministries of health and welfare, interior and justice, and registries in substitution maintenance therapy, road accidents and the National Police Agency.

Initial analyses found that individuals receiving treatment had a higher risk to be involved in car accidents than the general adult population or those without methadone maintenance treatment. Further tests showed that individuals receiving treatment were at three times higher risk of collisions than individuals not receiving treatment, particularly in the first 90 days.

These findings may help individuals undergoing methadone maintenance treatment manage their risk of motor vehicle collisions. Further investigation is needed to reveal the underlying mechanisms of methadone-related impairment of driving ability.

A vicious cycle of neuropathological, cognitive and behavioural sequelae of repeated opioid overdose

In the midst of an escalating U.S. opioid crisis, the immediate focus of public health interventions is on fatal overdose prevention. Few studies, however, have sought to examine the long-term health consequences of exposure to repeated nonfatal opioid overdose. We reviewed recent literature to examine three corresponding downstream health outcomes of repeated overdose: a) neurodegenerative processes; b) cognition and memory; and c) overdose risk behaviours. We found a remarkable congruency among available biochemical and cognitive data on how nonfatal overdose precipitates various pathological feedforward and feedback loops that affect people who use opioids for years to come. We found however that downstream behavioural implications of neurodegenerative and cognitive sequelae are less studied despite being most proximal to an overdose. Findings point to a vicious cycle of nonfatal overdose leading to neurodegeneration - closely resembling Alzheimer Disease - that results in cognitive decline that in turn leads to potentially reduced adherence to safe drug use behaviours. The collected evidence not only brings into the focus the long-term health consequences of nonfatal overdose from the perspectives of biology, neuroscience, and public health, but also creates new cross-disciplinary context and awareness in the research and public health community that should benefit people at risk.

Exploring the Effects of Vitamin D Supplementation on Cognitive Functions and Mental Health Status in Subjects Under Methadone Maintenance Treatment

OBJECTIVES

Vitamin D deficiency may be linked to several mental complications including cognitive deficits, depression, and anxiety in patients under methadone maintenance treatment (MMT). This study was designed to explore the effect of vitamin D supplementation on cognitive functions and mental health parameters in subjects under MMT.

METHODS

This randomized, double-blinded, placebo-controlled clinical trial was carried out among 64 patients under MMT. Participants were randomly allocated to receive either 50,000 IU vitamin D supplements (n = 32) or placebo (n = 32) every 2 weeks for 24 weeks. Cognitive functions and mental health parameters were taken at baseline and posttreatment to evaluate relevant variables.

RESULTS

After the 24-week intervention, compared with the placebo, serum 25(OH) vitamin D levels significantly increased in participants who received vitamin D supplements (β 14.50; 95% confidence interval [CI], 13.17-15.83; P < 0.001). In addition, compared with the placebo, subjects who received vitamin D had a significant reduction in Iowa Gambling Task (β -6.25; 95% CI, -8.60 to -3.90; P < 0.001), and significant increases in Verbal Fluency Test (β 2.82; 95% CI, 0.78-4.86; P = 0.007), Immediate Logic Memory (β 1. 32; 95% CI, 0.27-2.37; P = 0.01), Reverse Digit Span (β 2.06; 95% CI, 1.18-2.94; P < 0.001) and visual working memory (β 0.75; 95% CI, 0.33-1.16; P = 0.001). Also, vitamin D supplementation significantly improved BDI (β -2.76; 95% CI, -3.97 to -1.55; P < 0.001) compared with the placebo. When we applied Bonferroni correction, LM-Immediate (P = 0.07) became nonsignificant, and other mental health parameters did not alter.

CONCLUSIONS

Overall, taking 50,000 IU vitamin D supplements every 2 weeks for 24 weeks by patients under MMT had beneficial effects on cognitive functions and some mental health parameters. Further studies are needed to confirm our findings.

Prevalence and correlates of multiple non-fatal opioid overdoses among people who inject drugs who utilise needle syringe programs in Australia

BACKGROUND

Non-fatal overdose (NFOD) is a major cause of morbidity among people who inject drugs (PWID) and multiple NFOD is associated with increased risk of fatal overdose. Despite this, few studies have examined the prevalence and correlates of drug-specific multiple NFOD. The current study aimed to determine the prevalence and correlates of recent multiple non-fatal opioid overdose (NFOOD) among PWID who access needle syringe programs (NSPs) in Australia.

METHODS

The Australian Needle and Syringe Program Survey is conducted annually and was conducted at 46 sites across Australia in 2019. Participation involves completion of a self-administered questionnaire and a capillary dried blood spot for HIV and hepatitis C virus testing. In 2019, respondents who reported a minimum of one NFOOD in the previous 12 months (recent NFOOD) were asked to complete supplementary questions regarding their last NFOOD. Bivariate and multivariate logistic regression were used to determine factors independently associated with multiple recent NFOOD.

RESULTS

A total of 222 respondents reported recent NFOOD. Respondents were predominantly male (59%), one third (39%) were aged less than 39 years and 73% reported last injecting heroin at their last NFOOD. One in two respondents (48%, n = 107) reported multiple opioid overdoses (median 3, interquartile range 2-5). The odds of reporting multiple NFOOD were higher among respondents who reported injecting in a public location at their last NFOOD (adjusted odds ratio [AOR] 2.10, 95% CI 1.14-3.90, p = 0.018) and benzodiazepine use in the 12 h prior to NFOOD (AOR 2.74, 95% CI 1.50-4.99, p = 0.001).

CONCLUSIONS

Multiple NFOOD was prevalent among PWID who utilised NSPs who reported recent NFOOD. Public injecting and benzodiazepine use were associated with increased risk of multiple NFOOD, and there is a need for interventions specifically targeting PWID who report these high risk injecting practices.

Cognitive function in methadone maintenance patients compared with abstinent opioid users

BACKGROUND

Opioid is the second most prevalent illicit drug worldwide, whose consumption is very high in Iran, due to Iran's geographical proximity to producing countries. Methadone maintenance therapy is one of the most prevalent and accepted methods of substance abuse treatment. Nevertheless, cognitive disorders have been reported as one of its complications.

AIM

This study was conducted to evaluate cognitive impairment in methadone maintenance patients (MMPs) and to compare it with abstinent opioid users (AOUs).

MATERIALS AND METHODS

This cross-sectional analytical study was performed on 25 MMPs and 25 AOUs. Samples were selected through convenience sampling method whereby a self-made questionnaire was distributed among them to assess demographic information, clinical variables such as methadone and opioid use history, underlying disease and medication history, as well as 13-item Beck depression inventory. Then, they were interviewed using the Montreal Cognitive Assessment (MoCA) questionnaire.

RESULTS

Significant differences were found in MoCA questionnaire total scores (p = 0.018) and orientation to time and place dimension (p = 0.008) between the two groups, with the mean scores being higher in AOU group. Duration of opioid use was the only factor influencing cognitive assessment score in both Groups. (p = 0.029).

CONCLUSION

We suggest monitoring and assessing cognition function in patients receiving methadone especially for those with a long history of opioid use.

Comparison of psychological symptoms and cognitive functions in patients under maintenance treatment with methadone or buprenorphine, current opioid users and healthy subjects

Methadone and buprenorphine can affect the psychological symptoms and cognitive functioning of substance users. This study aimed to compare psychological symptoms and neuropsychological functioning in methadone maintenance patients (MMP), buprenorphine maintenance patients (BMP), current opioid users, and healthy subjects. One hundred and twenty participants (30 in each group) matched for age, sex, and education completed the Symptom Checklist-90-Revised (SCL-90-R) and a battery of neuropsychological tests including the Wisconsin Card Sorting Test (WCST), Wechsler Memory Scale (WMS-IV), and Stroop Color-Word Test (SCWT) assessing executive functioning, working memory, and attention, respectively. Overall, opioid users showed more severe psychological symptoms compared to healthy subjects. MMP and BMP had intermediate scores in SCL-90-R subscales; however, BMP had fewer severe symptoms compared to the MMP group. In terms of cognitive functioning, healthy subjects and current users demonstrated the best and the worst performance, respectively. Also, BMP outperforms MMP on executive functions and attention. However, the MMP had a better performance in WMS (visual memory). Patients receiving maintenance treatment had fewer psychological symptoms and better cognitive performance compared to opioid users. BMP had a better profile in all psychological symptoms and better performance in executive functions and selective attention compared to the MMP suggesting buprenorphine may be a better choice for the treatment of opioid-dependent patients.

The Alcohol and Drug Cognitive Enhancement (ACE) Screening Tool: A simple and brief questionnaire to screen for cognitive impairment in substance use disorder treatment services

The objective of this study was to determine the test-retest reliability; construct and criterion validity; and test operating characteristics of a newly developed cognitive impairment risk factor screening instrument, the Alcohol and Drug Cognitive Enhancement (ACE) Screening Tool. Participants in the validation study were 129 adults with substance use disorder (SUD) enrolled in residential SUD treatment services and 209 normal controls. Test and retest data were available for 36 participants with SUD and 40 normal control individuals on the ACE Screening Tool. Test-retest reliability was excellent (ICC = 0.97). The ACE Screening Tool was significantly correlated with the Montreal Cognitive Assessment (MoCA), Behavior Rating Inventory of Executive Functioning-Adult Version (BRIEF-A), Test of Premorbid Functioning (TOPF) and Five Point Test, establishing construct validity. Criterion validity was established using a ternary severity variable constructed using results obtained on the MoCA and BRIEF-A. Test operating characteristics analysis showed 93% sensitivity, 46% specificity, 33% positive predictive power, and 96% negative predictive power using a cut-score of >3. Those high levels of sensitivity and negative predictive power indicated that the tool would likely detect cognitive impairment when present and should therefore be considered suitable as an initial screening tool for cognitive impairment in individuals attending SUD services.

Impulsivity and craving in subjects with opioid use disorder on methadone maintenance treatment

BACKGROUND

Methadone maintenance treatment (MMT) is effective in decreasing opioid use or facilitating abstinence. Previous studies using small opioid use disorder samples suggest that cognitive impairments including impulsivity and executive functions may partially improve on MMT, but a range of deficits may persist. However, systematic assessments with larger samples are needed to confirm the profile of cognitive functions on MMT.

METHODS

We assessed four types of impulsivity (delay discounting, reflection impulsivity, risk taking and motoric impulsivity), executive functioning (spatial working memory, paired associative learning and strategic planning) and drug cue-induced craving in a relatively large population (115 MMT patients, 115 healthy controls). The relationships between impulsivity, drug cue-induced craving and addiction-related variables were also assessed.

RESULTS

Delay discounting, as well as drug cue-induced craving was increased in patients, while motoric impulsivity was lower than in controls. Paired associative learning was additionally impaired, which was explained by increased depression and anxiety levels in patients. Within the MMT group, the delay discounting and drug-cue induced craving scores were positively correlated with self-reported urgency, but unrelated to methadone dosage, duration on methadone, withdrawal symptoms, or presence of nicotine dependence.

CONCLUSIONS

Our findings highlight increased delay discounting and cue-induced craving in MMT patients suggesting a potential role for trait effects in delay discounting. Although previous smaller studies have shown impaired executive function, in our large sample size on chronic MMT we only observed impaired associative learning related to depressive and anxiety symptoms highlighting a role for managing comorbid symptoms to further optimize cognitive function.

Reasons for Increasing Daily Methadone Maintenance Dosage among Deceptive Patients: A Qualitative Study

Methadone maintenance treatment might be commonly associated with lying for several causes or manipulating psychiatrists and therapists by a number of patients. Deceptive patients tend to manipulate their psychiatrists for multiple causes. This study aims to improve clinicians’ therapeutic decision-making by identifying the reasons for increasing daily methadone maintenance dosage among deceptive patients. One hundred ninety-six patients undergoing the Methadone Maintenance Treatment (MMT) with no statistically significant difference between the overall Addiction Severity Index (ASI) scores at different doses of methadone (< 60 mg/d and ≥ 60 mg/d) and Ahvaz Reality Distortion Inventory (ARDI) scores > 30, were examined in the current qualitative study with multiple semi-structural interviews about the reasons for increasing daily methadone maintenance dosage. The investigation results revealed that the most common reasons for increasing daily methadone maintenance dosage among deceptive patients were opium craving, patient willingness to feel euphoria, fear of the withdrawal signs, earn money through the sale of surplus methadone, improve the symptoms of physical and psychiatric comorbidity, forgetting painful memories, curiosity, the influence of others, sexual issues, feeling of well-being, and appearance changes. Given these reasons, any increase in daily methadone maintenance dosage is not necessarily accompanied by improvement in the clinical condition of patients. However, clinicians can make the most appropriate therapeutic decision by putting the psychological assessments and clinical interviews into play.

Hospitalisations for non-fatal overdose among people with a history of opioid dependence in New South Wales, Australia, 2001-2018: Findings from the OATS retrospective cohort study

BACKGROUND

To examine, among a cohort of opioid dependent people with a history of opioid agonist treatment (OAT), the frequency and incidence rates of non-fatal overdose (NFOD) hospital separations over time, by age and sex.

METHODS

Retrospective cohort study of people with a history of OAT using state-wide linked New South Wales (NSW) data. The incidence of NFOD hospital separations involving an opioid, sedative, stimulant or alcohol was defined according to the singular or combination of poisoning/toxic effect using ICD-10-AM codes. Crude incidence rates were calculated by gender, age group and calendar year.

RESULTS

There were 31.8 (31.3-32.3) NFOD per 1,000 person-years (PY). Opioid NFOD incidence was higher in women than men: incidence rate ratio (IRR) 1.11 per 1,000PY; 95 %CI: [1.06-1.17]; women had higher sedative NFOD rates than men, IRR 1.27 per 1,000PY [1.21-1.34]. Participants ≤25 years, 26-30yrs, and 31-35yrs had higher incidence of opioid NFOD compared to 46+yrs, with IRRs of: 1.45 per 1,000PY; [1.32-1.59]; 1.20 per 1,000PY; [1.11-1.30] and 1.22 per 1,000PY; [1.13-1.32], respectively. Between 2006-7 and 2016-17, the cohort accounted for 19 % of NSW opioid NFOD episodes, 12 % of sedative, 14 % of stimulant and 5 % of acute alcohol-related NFOD.

CONCLUSIONS

Hospital stays due to NFOD are a relatively frequent occurrence among opioid-dependent people. There are clear differences in rates and substances involved by sex, age and over time. Evidence-based interventions that prevent overdose among people who are opioid dependent need to be delivered to scale, including widespread community provision of naloxone.

Does a hypoxic injury from a non-fatal overdose lead to an Alzheimer Disease?

Long term consequence of non-fatal overdose in people who use opioids are not well understood. The intermittent exposure to non-fatal overdose leads to a tauopathy that is often accompanied by abrogated neuroprotective response, abnormal amyloid processing and other pathologies. The scope and limitations of available literature are discussed including neuropathologies associated with opioid and overdose exposures, contributing comorbidities and proteinopathies. Contrasting postmortem data of overdose victims with animal models of opioid neuropathologies and hypoxic injury paints a picture distinct from other proteinopathies as well as effects of moderate opioid exposure. Furthermore the reported biochemical changes and potential targets for therapeutic intervention were mapped pointing to underlying imbalance between tau kinases and phosphatases that is characteristic of Alzheimer Disease.

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.

The effect of crocin (the main active saffron constituent) on the cognitive functions, craving, and withdrawal syndrome in opioid patients under methadone maintenance treatment

Individuals under methadone maintenance treatment (MMT) programs are susceptible to several complications, including withdrawal syndrome, craving, and cognitive deficits. This study was designed to elevate the effect of crocin administration on withdrawal syndrome, craving, and cognitive function in subjects under MMT programs. It was a clinical trial that was conducted among 60 patients referred to Soltan Mirahmad Clinic for addict patients in Kashan, Iran. The patients were allocated to two groups including placebo and intervention groups. The intervention group received 30 mg/day crocin (n = 30) and placebo (n = 30) once a day, in 12 weeks. Withdrawal syndrome, craving, and cognitive function parameters were measured before and after the intervention in subjects under MMT programs. Compared with the placebo group, crocin resulted in a significant improvement in craving score (p = .03), and withdrawal symptoms score (p = .01) in the intervention group. In addition, crocin supplementation did not affect cognitive function parameters (e.g., TMT, FAS test, and DGSP score). Overall, crocin supplementation for 12 weeks to patients under MMT programs had beneficial effects on craving and withdrawal symptoms score, but did not affect the cognitive function parameters.

Association between the brief inventory of neurocognitive impairment (BINI) and objective cognitive testing among persons with opioid use disorders in drug treatment

The current study examined the association between subjective cognitive dysfunction and objective test performance in persons enrolled in drug treatment and stabilized on methadone maintenance therapy (MMT). A total of 177 participants completed the self-reported brief inventory of neurocognitive impairment (BINI) and NIH Toolbox test battery. In participants with neurocognitive dysfunction, scores on all BINI subscales were negatively associated with objective performance on the NIH Toolbox (BINI Global r = -0.26, p = 0.01; BINI Subscales ranging -0.22 to -0.32, all p's < 0.03). Using cutoff scores, results showed participants who scored above the cutoff on the BINI Learning subscale demonstrated significant evidence of objective neurocognitive dysfunction on the NIH Toolbox (65% vs. 35%; χ² = 6.57, p = 0.02), suggesting possible clinical utility. Future studies are needed to determine the feasibility of using the BINI to inform the accommodation of patients with specific neurocognitive profiles to optimize treatment outcomes.

Cognitive profiles in persons with opioid use disorder enrolled in methadone treatment

Cognitive impairment is common in persons with opioid use disorder and associated with poor treatment outcomes, including elevated risk for relapse. Much less is known about the underlying structure of these deficits and the possible presence of cognitive phenotypes. A total of 177 adults (average 42.2 years of age, 52.0% male, 65.5% Caucasian) enrolled in a methadone maintenance treatment program completed the NIH Toolbox as part of a larger project. Cluster analyses revealed a 2-cluster solution-persons with intact cognitive function in all domains (n = 93; Intact) and those with impairments on tests of attention and executive function (n = 83; Impaired). Follow-up analyses revealed that the Impaired group was slightly older, more likely to self-identify as a racial/ethnic minority, and less likely to report consuming alcohol four or more times per week. These findings suggest the existence of distinct cognitive profiles in persons with opioid use disorder and encourage further examination, particularly studies to examine the possible benefits of routine screening for cognitive impairment as part of substance use treatment.

Protocol for a multi-site study of the effects of overdose prevention education with naloxone distribution program in Skåne County, Sweden

BACKGROUND

Continuously high rates of overdose deaths in Sweden led to the decision by the Skåne County to initiate the first regional take-home naloxone program in Sweden. The project aims to study the effect of overdose prevention education and naloxone distribution on overdose mortality in Skåne County. Secondary outcome measures include non-fatal overdoses and overdose-related harm in the general population, as well as cohort-specific effects in study participants regarding overdoses, mortality and retention in naloxone program.

METHODS

Implementation of a multi-site train-the-trainer cascade model was launched in June 2018. Twenty four facilities, including opioid substitution treatment units, needle exchange programs and in-patient addiction units were included for the first line of start-up, aspiring to reach a majority of individuals at-risk within the first 6 months. Serving as self-sufficient naloxone hubs, these units provide training, naloxone distribution and study recruitment. During 3 years, questionnaires are obtained from initial training, follow up, every sixth month, and upon refill. Estimated sample size is 2000 subjects. Naloxone distribution rates are reported, by each unit, every 6 months. Medical diagnoses, toxicological raw data and data on mortality and cause of death will be collected from national and regional registers, both for included naloxone recipients and for the general population. Data on vital status and treatment needs will be collected from registers of emergency and prehospital care.

DISCUSSION

Despite a growing body of literature on naloxone distribution, studies on population effect on mortality are scarce. Most previous studies and reports have been uncontrolled, thus not being able to link naloxone distribution to survival, in relation to a comparison period. As Swedish registers present the opportunity to monitor individuals and entire populations over time, conditions for conducting systematic follow-ups in the Swedish population are good, serving the opportunity to study the impact of large scale overdose prevention education and naloxone distribution and thus fill the knowledge gap.

TRIAL REGISTRATION

Naloxone Treatment in Skåne County - Effect on Drug-related Mortality and Overdose-related Complications, NCT03570099, registered on 26 June 2018.

Maternal responsivity and oxytocin in opioid-dependent mothers

Although prenatal opioid exposure and postnatal withdrawal (neonatal abstinence syndrome) are associated with infant neurobehavioral deficits, little is known about the impact of continued maternal opioid treatment in the postnatal period on maternal responsivity and relationship to mother's oxytocin release during dyadic interactions in the Still Face paradigm. Mother and infant dyads (N = 14) were recruited and comprised of mothers on opioid replacement throughout pregnancy and postpartum (opioid-exposed group, n = 7) and a demographically controlled, non-exposed group (n = 7). Salivary oxytocin was collected following 10 min of infant separation before and immediately after a 6-min Still Face paradigm. Oxytocin measures correlated strongly with sensitive and prosocial maternal behaviors in response to infant initiation. Opioid-exposed compared to non-exposed mothers had significantly lower pre-test to post-test rise in salivary oxytocin concentration level as well as fewer sensitive behaviors during the reunion condition of the Still Face paradigm. Maternal opioid dependence during early infancy may impair maternal responsivity and sensitivity through suppression of the oxytocin reflex to infant stimulation.

Global patterns of opioid use and dependence: harms to populations, interventions, and future action

We summarise the evidence for medicinal uses of opioids, harms related to the extramedical use of, and dependence on, these drugs, and a wide range of interventions used to address these harms. The Global Burden of Diseases, Injuries, and Risk Factors Study estimated that in 2017, 40·5 million people were dependent on opioids (95% uncertainty interval 34·3-47·9 million) and 109 500 people (105 800-113 600) died from opioid overdose. Opioid agonist treatment (OAT) can be highly effective in reducing illicit opioid use and improving multiple health and social outcomes-eg, by reducing overall mortality and key causes of death, including overdose, suicide, HIV, hepatitis C virus, and other injuries. Mathematical modelling suggests that scaling up the use of OAT and retaining people in treatment, including in prison, could avert a median of 7·7% of deaths in Kentucky, 10·7% in Kiev, and 25·9% in Tehran over 20 years (compared with no OAT), with the greater effects in Tehran and Kiev being due to reductions in HIV mortality, given the higher prevalence of HIV among people who inject drugs in those settings. Other interventions have varied evidence for effectiveness and patient acceptability, and typically affect a narrower set of outcomes than OAT does. Other effective interventions focus on preventing harm related to opioids. Despite strong evidence for the effectiveness of a range of interventions to improve the health and wellbeing of people who are dependent on opioids, coverage is low, even in high-income countries. Treatment quality might be less than desirable, and considerable harm might be caused to individuals, society, and the economy by the criminalisation of extramedical opioid use and dependence. Alternative policy frameworks are recommended that adopt an approach based on human rights and public health, do not make drug use a criminal behaviour, and seek to reduce drug-related harm at the population level.

The Effects of Opioids on HIV Neuropathogenesis

HIV associated neurocognitive disorders (HAND) are a group of neurological deficits that affect approximately half of people living with HIV (PLWH) despite effective antiretroviral therapy (ART). There are currently no reliable molecular biomarkers or treatments for HAND. Given the national opioid epidemic, as well as illegal and prescription use of opioid drugs among PLWH, it is critical to characterize the molecular interactions between HIV and opioids in cells of the CNS. It is also important to study the role of opioid substitution therapies in the context of HIV and CNS damage in vitro and in vivo. A major mechanism contributing to HIV neuropathogenesis is chronic, low-level inflammation in the CNS. HIV enters the brain within 4–8 days after peripheral infection and establishes CNS reservoirs, even in the context of ART, that are difficult to identify and eliminate. Infected cells, including monocytes, macrophages, and microglia, produce chemokines, cytokines, neurotoxic mediators, and viral proteins that contribute to chronic inflammation and ongoing neuronal damage. Opioids have been shown to impact these immune cells through a variety of molecular mechanisms, including opioid receptor binding and cross desensitization with chemokine receptors. The effects of opioid use on cognitive outcomes in individuals with HAND in clinical studies is variable, and thus multiple biological mechanisms are likely to contribute to the complex relationship between opioids and HIV in the CNS. In this review, we will examine what is known about both HIV and opioid mediated neuropathogenesis, and discuss key molecular processes that may be impacted by HIV and opioids in the context of neuroinflammation and CNS damage. We will also assess what is known about the effects of ART on these processes, and highlight areas of study that should be addressed in the context of ART.

Intact responses to non-drug rewards in long-term opioid maintenance treatment

Disruption of non-drug reward processing in addiction could stem from long-term drug use, addiction-related psychosocial stress, or a combination of these. It remains unclear whether long-term opioid maintenance treatment (OMT) disrupts reward processing. Here, we measured subjective and objective reward responsiveness in 26 previously heroin-addicted mothers in >7 years stable OMT with minimal psychosocial stress and illicit drug use. The comparison group was 30 healthy age-matched mothers (COMP). Objective reward responsiveness was assessed in a two-alternative forced-choice task with skewed rewards. Results were also compared to performance from an additional 968 healthy volunteers (meta-analytic approach). We further compared subprocesses of reward-based decisions across groups using computational modelling with a Bayesian drift diffusion model of decision making. Self-reported responsiveness to non-drug rewards was high for both groups (means: OMT = 6.59, COMP = 6.67, p = 0.84, BF10 = 0.29), yielding moderate evidence against subjective anhedonia in this OMT group. Importantly, the mothers in OMT also displayed robust reward responsiveness in the behavioral task (t19 = 2.72, p = 0.013, BF10 = 3.98; d = 0.61). Monetary reward changed their task behavior to the same extent as the local comparison group (reward bias OMT = 0.12, COMP = 0.12, p = 0.96, BF10 = 0.18) and in line with data from 968 healthy controls previously tested. Computational modelling revealed that long-term OMT did not even change decision subprocesses underpinning reward behavior. We conclude that reduced sensitivity to rewards and anhedonia are not necessary consequences of prolonged opioid use.

Diagnostic precision of the Wisconsin Card Sorting Test in assessing cognitive deficits in substance use disorders

The Wisconsin Card Sorting Test (WCST) is a widely used neuropsychological instrument to assess executive functions related to cognitive flexibility and abstract reasoning. However, there is a lack of studies investigating the diagnostic precision of this instrument in substance use disorders. In this study, we aimed at assessing the sensitivity and specificity of the WCST in discriminating the performance of participants with substance use disorder with cognitive deficits and participants from the general population without cognitive deficits. The sample comprised three groups of participants with substance use disorders (opioid use disorder in harm reduction with methadone maintenance; opioid use disorder in treatment in a therapeutic community; alcohol use disorder in a therapeutic community) and a normative group of healthy adults. The total sample consisted of 587 participants that were assessed with cognitive tests for executive functions, general cognitive functioning, and self-reported depression. The results showed differences between groups in most WCST variables, providing evidence of discriminant validity for this test. Convergent validity was also established by weak to moderate correlations with general cognitive functioning. Cutoff points based on receiver operating characteristic (ROC) curves were calculated for the WCST variables. Overall, the WCST was sensitive to changes in cognitive flexibility and abstract reasoning that are key features of substance use disorders.

Profiles of visuospatial memory dysfunction in opioid-exposed and dependent populations

BACKGROUND

Chronic opioid exposure is common world-wide, but behavioural performance remains under-investigated. This study aimed to investigate visuospatial memory performance in opioid-exposed and dependent clinical populations and its associations with measures of intelligence and cognitive impulsivity.

METHODS

We recruited 109 participants: (i) patients with a history of opioid dependence due to chronic heroin use (n = 24), (ii) heroin users stabilised on methadone maintenance treatment (n = 29), (iii) participants with a history of chronic pain and prescribed tramadol and codeine (n = 28) and (iv) healthy controls (n = 28). The neuropsychological tasks from the Cambridge Neuropsychological Test Automated Battery included the Delayed Matching to Sample (DMS), Pattern Recognition Memory, Spatial Recognition Memory, Paired Associate Learning, Spatial Span Task, Spatial Working Memory and Cambridge Gambling Task. Pre-morbid general intelligence was assessed using the National Adult Reading Test.

RESULTS

As hypothesised, this study identified the differential effects of chronic heroin and methadone exposures on neuropsychological measures of visuospatial memory (p &lt; 0.01) that were independent of injecting behaviour and dependence status. The study also identified an improvement in DMS performance (specifically at longer delays) when the methadone group was compared with the heroin group and also when the heroin group was stabilised onto methadone. Results identified differential effects of chronic heroin and methadone exposures on various neuropsychological measures of visuospatial memory independently from addiction severity measures, such as injecting behaviour and dependence status.

Self-Rated Physical Health and Unmet Healthcare Needs among Swedish Patients in Opioid Substitution Treatment

Background

Individuals with opioid dependence are at increased risk of deteriorating health due to the lifestyle connected to heroin use. Barriers surrounding the healthcare system seem to hinder patients to seek help through conventional healthcare, even after entering opioid substitution treatment (OST), resulting in a high level of unmet healthcare needs. However, this field is still unexplored, with only a few studies focusing on general health within this population. The first step, in order to provide suitable and accessible primary healthcare, is to assess the extent of physical symptoms and unmet healthcare needs within the OST population, which, to this point, has been sparsely studied.

Aim

To assess OST patients' self-rated physical health and healthcare seeking behaviour.

Methods

Two-hundred and eighteen patients from four different OST sites answered a questionnaire regarding physical health and healthcare seeking.

Results

Patients in OST have a high degree of physical symptoms and a high degree of unmet healthcare needs. Sixty-six percent reported suffering from musculoskeletal pain. Fifty-six percent reported gastrointestinal symptoms. Genital problems and airway symptoms were reported by 47%, respectively, and dental problems were reported by 69% of the respondents. General unmet healthcare needs were reported by 82%. Musculoskeletal pain was positively correlated with having an unstable housing situation (AOR 4.26 [95% CI 1.73-10.48]), negatively correlated with male sex (AOR 0.45 [95% CI 0.22-0.91]), and positively correlated with age (AOR 1.04 [95% CI 1.01-1.07]). No statistically significant correlates of respiratory, gastrointestinal, genital, or dental symptoms were found.

Conclusion

Patients in OST carry a heavy burden of physical symptoms and unmet healthcare needs, potentially due to societal barriers. Patients' frequent visits to the OST clinics offer a unique opportunity to build a base for easily accessible on-site primary healthcare.

Cognitive function is largely intact in methadone maintenance treatment patients

OBJECTIVES

To confirm our previous findings of less cognitive impairments (based on cognitive screening tools) among methadone maintenance treatment (MMT) patients who achieved take-home dose (THD) privileges.

METHODS

a random sample of 65 Israeli MMT patients were studied using computerised, age and education standardised, cognitive domains (attention, executive function, memory, motor skills), and non-computerised phonetic and semantic verbal fluency.

RESULTS

Cognitive scores were within ±1 standard deviation (SD) of average for most domains, including non-verbal IQ, attention and motor skills. Verbal fluency and memory were >1 SD below average (mean = 84; z = -1.1 for both). Females were younger than the males and had poorer motor skills (P = 0.005) but better verbal memory (P < 0.0005). Opiate usage duration correlated with reaction time (P = 0.05) and inversely with verbal memory (P = 0.01). Overall cognitive function was poorest among 25 (38.5%) current drug users, and 6 (9.2%) lifetime schizophrenia patients. Cognitive domains were comparable between THD privileges subgroups.

CONCLUSIONS

Despite heterogeneity in MMT duration, abuse duration, substance use and psychiatric comorbidity, all performed within ±1 SD of average for age and education in most cognitive domains. Our findings challenge the notion of MMT as being synonymous with compromised cognition and may lead to reduced bias regarding cognitive function of MMT patients.

Impact of Substance Use Disorder Pharmacotherapy on Executive Function: A Narrative Review

Substance use disorders are chronic, relapsing, and harmful conditions characterized by executive dysfunction. While there are currently no approved pharmacotherapy options for stimulant and cannabis use disorders, there are several evidence-based options available to help reduce symptoms during detoxification and aid long-term cessation for those with tobacco, alcohol and opioid use disorders. While these medication options have shown clinical efficacy, less is known regarding their potential to enhance executive function. This narrative review aims to provide a brief overview of research that has investigated whether commonly used pharmacotherapies for these substance use disorders (nicotine, bupropion, varenicline, disulfiram, acamprosate, nalmefene, naltrexone, methadone, buprenorphine, and lofexidine) effect three core executive function components (working memory, inhibitory control and cognitive flexibility). While pharmacotherapy-induced enhancement of executive function may improve cessation outcomes in dependent populations, there are limited and inconsistent findings regarding the effects of these medications on executive function. We discuss possible reasons for the mixed findings and suggest some future avenues of work that may enhance the understanding of addiction pharmacotherapy and cognitive training interventions and lead to improved patient outcomes.

Effects of Opioid Dependence on Visuospatial Memory and Its Associations With Depression and Anxiety

Introduction: The cognitive impact of opioid dependence is rarely measured systematically in everyday clinical practice even though both patients and clinicians accept that cognitive symptoms often occur in the opioid-dependent population. There are only a few publications which utilized computerized neuropsychological tests to assess possible impairments of visuospatial memory in opioid-dependent individuals either receiving opioid replacement therapy (ORT) or during subsequent short-term abstinence and the effects of anxiety and depression. Methods: We assessed a cohort of 102 participants, comprising i) a stable opioid-dependent group receiving methadone maintenance treatment (MMT) (n = 22), ii) a stable opioid-dependent group receiving buprenorphine (BMT) (n = 20), iii) a current abstinent but previously opioid-dependent group (ABS) (n = 8), and iv) a control group who have never been dependent on opioids. The Cambridge Neuropsychological Automated Test Battery (CANTAB) neuropsychological tasks undertaken by participants included: Delayed Matching to Sample (DMS), Pattern Recognition Memory (PRM), Spatial Recognition Memory (SRM), and Paired Associate Learning (PAL) tasks. Three clinical measures were used to assess the severity of anxiety and depressive illness: Hospital Anxiety Scale-Hospital Anxiety Depression (HADA)-(HADD), Beck Depression Inventory (BDI), and Inventory of Depressive Symptomatology (self-report) (ISD-SR). Results: The methadone- and buprenorphine-treated groups showed significant impairments (p < 0.001) in visuospatial memory tasks but not the abstinent group. Impairments in visuospatial memory strongly correlated with higher mood and anxiety symptom severity scores (p < 0.001). Discussion: These results are broadly consistent with previous studies. Uniquely, though, here we report a strong relationship between visuospatial memory and depression and anxiety scores, which might suggest common illness mechanisms.

Cognitive and socio-cognitive functioning of chronic non-medical prescription opioid users

RATIONALE

Non-medical prescription opioid use (NMPOU) has become a major public health issue in the USA and is also increasing in Europe. However, little is known about neuropsychological associations of NMPOU-specifically regarding social cognition, which is essential for social functioning and treatability of opioid dependence. Previous studies with heroin users and opioid-substituted patients reported deficits in various cognitive functions, but these results are likely confounded by comorbid physical and psychiatric diseases, overdose-associated hypoxia, and adulteration of street heroin. Therefore, the purpose of the present study was to investigate social and non-social cognition in a relatively pure NMPOU sample taking opioid analgesics or antitussives.

METHODS

We assessed 23 individuals with NMPOU objectively confirmed by hair analyses and 29 opioid-naïve, healthy controls, employing a comprehensive neuropsychological test battery.

RESULTS

Significant impairments were found between NMPOU individuals and controls regarding the cognitive domains of attention (p < .01, Hedge's g = .85), declarative memory (p < .05, g = .66), and global cognitive empathy (p < .01, g = 0.99)-the latter included problems with emotion recognition from faces, voices, and complex scenes. Opioid hair concentrations transformed to morphine equivalents were negatively correlated with global cognitive empathy (r = - 0.52, p < .01), suggesting dose-dependent deficits.

CONCLUSION

In contrast to stimulant users primarily displaying deficits in emotional empathy, opioid users showed relatively selective impairments in measures of cognitive empathy, with dose-dependent effects suggesting potential opioid-induced deficits and involvement of the opioid-system in processes of cognitive empathy. These results have important implications for future interventions of opioid dependence targeting social functioning and consequently enhancing therapy outcome and preventing relapse.

Histopathological study of liver tissue due to methadone consumption and its effect on liver enzymes and inflammatory indices in rat

Background

Methadone (MET)-based treatment is currently one of the best known approaches in the treatment of opioid dependence. It is claimed that MET use exerts adverse effects on the performance of some organs, especially liver. Thus, the present study aims to investigate MET effects on the hepatic tissue as well as its effect on the hepatic enzyme levels and inflammatory markers in rats.

Materials and methods

Twenty-eight mature male Wistar rats underwent an 8-week treatment in four equal groups including the control group (an ordinary daily dietary regime) as well as the experimental groups 1, 2, and 3 (an ordinary daily dietary regime and gavage-fed on MET syrup for 5, 20, and 40 mg/kg body weight per day). Blood samples were collected from all rats in the beginning and end of the study to measure their hepatic enzyme levels and inflammatory markers. In the end, their livers were subjected to histological examinations.

Results

The mean serum levels of hepatic enzymes (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) increased considerably across all the three groups that had received various dosages of MET (5, 20, and 40 mg/kg) in the end of the study as compared to the beginning of the study (P<0.001). It was also found that the inflammatory indicators (interleukin-6, tumor necrosis factor-alpha, and C-reactive protein) rose significantly in the groups that had received various dosages of MET in contrast to the control group (P<0.01, P<0.001, and P<0.001, respectively). The histopathological images of the liver cross-sections revealed dosage-dependent tissue changes in the groups that had received various dosages of MET.

Conclusion

The present study tried to prove the adverse effects of MET in the development of liver damage. Since MET-based treatment is frequently prescribed by physicians for curing the addiction to narcotics, better strategies are required for its correct usage.

Acute effects of methadone on EEG power spectrum and event-related potentials among heroin dependents

Methadone as the most prevalent opioid substitution medication has been shown to influence the neurophysiological functions among heroin addicts. However, there is no firm conclusion on acute neuroelectrophysiological changes among methadone-treated subjects as well as the effectiveness of methadone in restoring brain electrical abnormalities among heroin addicts. This study aims to investigate the acute and short-term effects of methadone administration on the brain's electrophysiological properties before and after daily methadone intake over 10 weeks of treatment among heroin addicts. EEG spectral analysis and single-trial event-related potential (ERP) measurements were used to investigate possible alterations in the brain's electrical activities, as well as the cognitive attributes associated with MMN and P3. The results confirmed abnormal brain activities predominantly in the beta band and diminished information processing ability including lower amplitude and prolonged latency of cognitive responses among heroin addicts compared to healthy controls. In addition, the alteration of EEG activities in the frontal and central regions was found to be associated with the withdrawal symptoms of drug users. Certain brain regions were found to be influenced significantly by methadone intake; acute effects of methadone induction appeared to be associative to its dosage. The findings suggest that methadone administration affects cognitive performance and activates the cortical neuronal networks, resulting in cognitive responses enhancement which may be influential in reorganizing cognitive dysfunctions among heroin addicts. This study also supports the notion that the brain's oscillation powers and ERPs can be utilized as neurophysiological indices for assessing the addiction treatment traits.

Correlation of cytokines, BDNF levels, and memory function in patients with opioid use disorder undergoing methadone maintenance treatment

BACKGROUND

Patients with opioid use disorder (OUD) show memory deficiencies and impaired treatment outcomes. Emerging evidence suggests that opioid abuse activates proinflammatory processes by increasing cytokine production and impairing neuroprotection, which damages the memory function in OUD patients. Therefore, we investigated whether plasma-based inflammatory and neurotrophic markers correlate with memory function in OUD patients.

METHOD

OUD patients undergoing methadone maintenance therapy (MMT) were investigated and followed up for 12 weeks. Plasma tumor necrosis factor (TNF)-α, C-reactive protein (CRP), interleukin (IL)-6, transforming growth factor (TGF)-β1, brain-derived neurotrophic factor (BDNF) levels, and Wechsler Memory Scale-Revised (WMS-R) scores were assessed at baseline and after 12 weeks of MMT. Multiple linear regressions and generalized estimating equations (GEEs) were used to examine the correlation between cytokines and memory performance.

RESULTS

We enrolled 89 patients at baseline; 47 patients completed the end-of-study assessments. Although Pearson correlations showed that CRP and TGF-β1 levels were significantly, negatively associated with some memory indices, the results were not significant after correction. The GEE results, controlled for several confounding factors and multiple testing, showed that changes in TNF-α levels were negatively correlated with changes in the visual memory index (P = 0.01), and that changes in IL-6 levels were negatively correlated with changes in the verbal memory index (P = 0.009).

CONCLUSION

Memory performance, TNF-α, and IL-6 levels in OUD patients were negative correlated. Additional studies on regulating TNF-α and IL-6 expression to improve memory function in OUD patients might be warranted.

Illegal Drug-Attributable Mortality and Potential Years of Life Lost in Canada 2002: Implications for Prevention and Policy

The article estimates the deaths and years of life lost due to use of illegal drugs in Canada in the year 2002. In 2002, for Canada, 1,695 deaths were attributable to illegal drug use, 0.8% of all deaths: 1,183 of men (1.0%) and 512 in women (0.5%). Main causes of illegal drug use-attributable death were drug overdose, suicide, and hepatitis C. In 2002 in total, 62,110 years of life were lost prematurely, 42,306 years among men and 19,805 years among women. Illegal drug use constitutes a major contributor to the burden of mortality in Canada. A mixture of prevention and harm reduction measures is proposed to reduce the burden of mortality associated with drug use.

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.

Self-reported cognitive scales in a US National Survey: reliability, validity, and preliminary evidence for associations with alcohol and drug use

AIMS

To evaluate relationships between measures of cognitive functioning and alcohol or drug use among adults (≥ 18 years) in the US general population.

DESIGN

Two cognitive scales were created based on dimensionality and reliability of self-reported Executive Function Index items. Relationships between the two scales and validators were evaluated. Associations between the cognitive scales and past-year frequency of alcohol or drug use were estimated with adjusted odds ratios (aOR).

SETTING

United States, using the 2012-13 National Epidemiologic Survey on Alcohol and Related Conditions-III, a nationally representative adult sample selected by multi-stage probability sampling.

PARTICIPANTS

36 085 respondents.

MEASUREMENTS

Past-year substance use outcome variables categorized binge drinking, marijuana, cocaine, opioid, sedative/tranquilizer and stimulant use as frequent (at least weekly to daily), infrequent (any to two to three times/month) or no use, assessed by the Alcohol Use Disorder and Associated Disabilities Interview Schedule-5. Key predictors were the two cognitive scales. Construct validators included education and functional impairment. Covariates included age, gender, income and race/ethnicity.

FINDINGS

Nine cognitive items fitted a two-factor model (comparative fit index = 0.973): attention (five items) and executive functioning (four items). Both scales were associated positively with higher education (Ps < 0.001) and negatively with functional impairment (Ps < 0.001), demonstrating construct validity. Poorer attention was associated with frequent and infrequent binge drinking and use of drugs [aOR range = 1.07 (binge drinking) to 1.72 (stimulants), Ps ≤ 0.01]. Poorer executive functioning was associated with frequent binge drinking and use of drugs [aOR range = 1.22 (binge drinking) to 2.03 (cocaine), Ps < 0.001] and infrequent use of all drugs [aOR range = 1.19 (marijuana) to 1.63 (cocaine), Ps < 0.001].

CONCLUSIONS

Impairments in attention and executive functioning are positively associated with substance use in the US general population.

Factors associated with cognitive impairment in a cohort of older homeless adults: Results from the HOPE HOME study

BACKGROUND

We evaluated cognitive function and factors associated with cognitive impairment in a cohort of older homeless adults. We hypothesized that substance use and a history of traumatic brain injury would be associated with cognitive impairment.

METHODS

We recruited 350 homeless individuals aged ≥50 years using population-based sampling and conducted structured interviews and neuropsychological testing. We evaluated alcohol use with the Alcohol Use Disorder Identification Test, defining high-severity alcohol use as a total score ≥16 or ≥4 on the alcohol dependency sub-scale. We assessed global cognition with the Modified Mini-Mental State Test (3MS) and processing speed and executive function with the Trail Making Test (TMTB), defining impairment as performing 1.5 standard deviations below the standardized mean. We used multivariable logistic regression to examine the association between alcohol use and cognition.

RESULTS

Participants had a median age of 58 years [IQR 54-61], 76.7% were men, and 79.9% were African American. A quarter (25.1%) of participants met criteria for impairment on the 3MS; 32.9% met criteria for impairment on TMTB. In models adjusted for sociodemographic variables and health conditions, high-severity alcohol use was associated with global cognitive impairment (AOR 2.39, CI 1.19-4.79) and executive dysfunction (AOR 3.09, CI 1.61-5.92).

CONCLUSIONS

Older homeless adults displayed a prevalence of cognitive impairment 3-4 times higher than has been observed in general population adults aged 70 and older. Impaired cognition in older homeless adults could impact access to housing programs and the treatment of health conditions, including the treatment of alcohol use disorders.

Resting-State Neuroimaging and Neuropsychological Findings in Opioid Use Disorder during Abstinence: A Review

Dependence to opiates, including illicit heroin and prescription pain killers, and treatment of the opioid use disorder (OUD) have been longstanding problems over the world. Despite intense efforts to scientific investigation and public health care, treatment outcomes have not significantly improved for the past 50 years. One reason behind the continuing use of heroin worldwide despite such efforts is its highly addictive nature. Brain imaging studies over the past two decades have made significant contribution to the understanding of the addictive properties as to be due in part to biological processes, specifically those in the brain structure and function. Moreover, traditional clinical neuropsychology studies also contribute to the account in part for the treatment-refractory nature of the drug abuse. However, there is a gap between those studies, and the rates of relapse are still high. Thus, a multidisciplinary approach is needed to understand the fundamental neural mechanism of OUD. How does the brain of an OUD patient functionally and cognitively differ from others? This brief review is to compare and contrast the current literature on non-invasive resting state neuroimaging and clinical neuropsychological studies with the focus on the abstinence stage in OUD. The results show as follow:

Brain connectivity strength in the reward system, dysregulation of circuits associated with emotion and stress, enhanced beta and alpha power activity, and high impulsivity are induced by OUD.

Some recovery signs in cognition are demonstrated in OUD subjects after prolonged abstinence, but not in the subjects undergoing methadone treatment.

Normalization in the composition of brain oscillations especially in the temporal region is induced and restored by methadone treatment in roughly 6 months in mean duration for OUDs having a mean opioid-use history of 10 years.

We hope that the review provides valuable implications for clinical research and practice and paves a new insight into the future path to the identification of potential biomarkers and clinical outcome predictors in OUD in the domains of brain regions, functions, and behaviors.