Neuropsychological functioning and chronic methadone use: A systematic review and meta-analysis

Practitioner perspectives on working with older patients in opioid agonist treatment (OAT) in Norway: opportunities and challenges

BACKGROUND

Norway has a growing proportion of ageing opioid agonist treatment (OAT) patients, with 42% of the 8300 Norwegian OAT patients aged over 50 in 2022. This study aims to explore practitioners' views and experiences from treatment of ageing OAT patients.

METHODS

Data were collected as a series of semi-structured interviews with treatment staff (roles interviewed: doctor, psychologist, social worker, nurse, and learning disability nurse). Participants were recruited from three OAT outpatient clinics, one with an urban catchment area and two with a mix of urban and rural. The interviews incorporated questions on patients' somatic and mental health, strengths and weaknesses of the service for this group, and patients' quality of life.

RESULTS

Older patients were perceived to be more often stable in terms of substance use and housing situation, but also experiencing some key challenges in terms of cognitive impairment, loneliness and isolation, and comorbidities. Both the practitioner-patient relationship and healthcare interactions outside OAT had the potential to impact treatment quality positively or negatively depending on how they were managed.

CONCLUSIONS

Treating older patients in a way that respects and enhances their dignity is important. We argue that this requires better services for those whose functioning is impacted by cognitive impairment/dementia, an age-informed treatment model for this patient group, along with urgent work to improve municipal-level services given practitioners describe them as unacceptable in certain areas.

Neurocognitive Functions After 6-Month Buprenorphine (Naloxone)-Based Opioid Agonist Maintenance Treatment: A Controlled Prospective Study

BACKGROUND

Medications for opioid use disorder (OUD) may influence neurocognitive functions. Inadequate power, confounders, and practice effects limit the validity of the existing research. We examined the change in cognitive functions in patients with OUD at 6-month buprenorphine (naloxone) posttreatment and compared the cognitive performance of the buprenorphine-treated group with control subjects.

METHODS

We recruited 498 patients with OUD within a week of initiating buprenorphine. Assessments were done twice-at baseline and 6 months. Those abstinent from illicit opioids and adherent to treatment (n = 199) underwent follow-up assessments. Ninety-eight non-substance-using control subjects were recruited from the community. The neurocognitive assessments comprised the Wisconsin Card Sorting Test, Iowa Gambling Task, Trail-Making Tests A and B (TMT-A and TMT-B), and verbal and visual N-Back Test. We controlled for potential effect modifiers.

RESULTS

Twenty-five of the 32 test parameters significantly improved with 6 months of buprenorphine treatment; 20 parameters withstood corrections for multiple comparisons (P < 0.001). The improved test domains spread across cognitive tests: Wisconsin Card Sorting Test (perseverative errors and response, categories completed, conceptual responses), TMTs (time to complete), verbal and visual N-Back Tests (hits, omission, and total errors). After treatment, OUD (vs control subjects) had less perseverative response and error (P < 0.001) and higher conceptual response (P = 0.004) and took lesser time to complete TMT-A (P < 0.001) and TMT-B (P = 0.005). The baseline neurocognitive functions did not differ between those who retained and those who discontinued the treatment.

CONCLUSION

Cognitive functions improve in patients with OUD on buprenorphine. This improvement is unlikely to be accounted for by the practice effect, selective attrition, and potential confounders.

Investigating brain dynamics and their association with cognitive control in opioid use disorder using naturalistic and drug cue paradigms

Objectives

Opioid use disorder (OUD) impacts millions of people worldwide. The prevalence and debilitating effects of OUD present a pressing need to understand its neural mechanisms to provide more targeted interventions. Prior studies have linked altered functioning in large-scale brain networks with clinical symptoms and outcomes in OUD. However, these investigations often do not consider how brain responses change over time. Time-varying brain network engagement can convey clinically relevant information not captured by static brain measures.

Methods

We investigated brain dynamic alterations in individuals with OUD by applying a new multivariate computational framework to movie-watching (i.e., naturalistic; N=76) and task-based (N=70) fMRI. We further probed the associations between cognitive control and brain dynamics during a separate drug cue paradigm in individuals with OUD.

Results

Compared to healthy controls (N=97), individuals with OUD showed decreased variability in the engagement of recurring brain states during movie-watching. We also found that worse cognitive control was linked to decreased variability during the rest period when no opioid-related stimuli were present.

Conclusions

These findings suggest that individuals with OUD may experience greater difficulty in effectively engaging brain networks in response to evolving internal or external demands. Such inflexibility may contribute to aberrant response inhibition and biased attention toward opioid-related stimuli, two hallmark characteristics of OUD. By incorporating temporal information, the current study introduces novel information about how brain dynamics are altered in individuals with OUD and their behavioral implications.

Metabolic and functional substrates of impulsive decision-making in individuals with heroin addiction after prolonged methadone maintenance treatment

Elevated impulsivity has been frequently reported in individuals with opioid addiction receiving methadone maintenance therapy (MMT), but the underlying neural mechanisms and cognitive subprocesses are not fully understood. We acquired functional magnetic resonance imaging (fMRI) data from 37 subjects with heroin addiction receiving long-term MMT and 33 healthy controls who performed a probabilistic reversal learning task, and measured their resting-state brain glucose using fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET). Subjects receiving MMT exhibited significantly elevated self-reported impulsivity, and computational modeling revealed a marked impulsive decision bias manifested as switching more frequently without available evidence. Moreover, this impulsive decision bias was associated with the dose and duration of methadone use, irrelevant to the duration of heroin use. During the task, the switch-related hypoactivation in the left rostral middle frontal gyrus was correlated with the impulsive decision bias while the function of reward sensitivity was intact in subjects receiving MMT. Using prior brain-wide receptor density data, we found that the highest variance of regional metabolic abnormalities was explained by the spatial distribution of μ-opioid receptors among 10 types of neurotransmitter receptors. Heightened impulsivity in individuals receiving prolonged MMT is manifested as atypical choice bias and noise in decision-making processes, which is further driven by deficits in top-down cognitive control, other than reward sensitivity. Our findings uncover multifaceted mechanisms underlying elevated impulsivity in subjects receiving MMT, which might provide insights for developing complementary therapies to improve retention during MMT.

Effects of Abstinence From Opioid on Neuropsychological Performance in Men With Opioid Use Disorder: A Longitudinal Study

OBJECTIVES

Impairments in neuropsychological functioning (mainly memory, learning, attention, and executive functioning) among persons with long-term opioid use disorder (OUD) have been widely reported, with few studies suggesting that these are not permanent and can improve with abstinence. Thus, present study aimed to evaluate the neuropsychological functioning in persons with OUD and examine the effects of abstinence on the same over a period 8 weeks.

METHODS

A total of 50 patients with diagnosis of OUD as per the Diagnostic and Statistical Manual of Mental Disorders , Fifth Edition ( DSM-5 ) criteria underwent serial longitudinal neuropsychological assessments for executive functioning, attention and concentration, and verbal and nonverbal memory at baseline, 2 weeks, and 8 weeks of abstinence.

RESULTS

The mean performance scores representative of attention, concentration, verbal memory, and nonverbal memory showed significant improvement in the initial 2 weeks, and executive functioning showed significant improvement by 8 weeks of abstinence (all P 's < 0.01). A significant negative correlation was found between the duration of opioid use and performance on verbal memory tests (0.014), the frequency of intake per day and performance on nonverbal memory and executive functioning tests, and the severity of opioid dependence and performance on nonverbal memory test (0.019).

CONCLUSIONS

Neuropsychological functioning in certain domains was associated with the duration of opioid use, the frequency of daily opioid intake, and the severity of opioid dependence among persons with OUD at baseline. It showed significant improvement in domains of attention, concentration, verbal and nonverbal memory, and executive functions over a period of 8 weeks of abstinence.

FORWARDS-1: an adaptive, single-blind, placebo-controlled ascending dose study of acute baclofen on safety parameters in opioid dependence during methadone-maintenance treatment-a pharmacokinetic-pharmacodynamic study

Background

Treatment of opiate addiction with opiate substitution treatment (e.g. methadone) is beneficial. However, some individuals desire or would benefit from abstinence but there are limited options to attenuate problems with opiate withdrawal. Preclinical and preliminary clinical evidence suggests that the GABA-B agonist, baclofen, has the desired properties to facilitate opiate detoxification and prevent relapse. This study aims to understand whether there are any safety issues in administering baclofen to opioid-dependent individuals receiving methadone.

Methods

Opiate-dependent individuals (DSM-5 severe opioid use disorder) maintained on methadone will be recruited from addiction services in northwest London (NHS and third sector providers). Participants will be medically healthy with no severe chronic obstructive pulmonary disease or type 2 respiratory failure, no current dependence on other substances (excluding nicotine), no current severe DSM-5 psychiatric disorders, and no contraindications for baclofen or 4800 IU vitamin D (placebo). Eligible participants will be randomised in a 3:1 ratio to receive baclofen or placebo in an adaptive, single-blind, ascending dose design. A Bayesian dose-escalation model will inform the baclofen dose (10, 30, 60, or 90 mg) based on the incidence of ‘dose-limiting toxicity’ (DLT) events and participant-specific methadone dose. A range of respiratory, cardiovascular, and sedative measures including the National Early Warning Score (NEWS2) and Glasgow Coma Scale will determine DLT. On the experimental day, participants will consume their usual daily dose of methadone followed by an acute dose of baclofen or placebo (vitamin D3) ~ 1 h later. Measures including oxygen saturation, transcutaneous CO₂, respiratory rate, QTc interval, subjective effects (sedation, drug liking, craving), plasma levels (baclofen, methadone), and adverse events will be obtained using validated questionnaires and examinations periodically for 5 h after dosing.

Discussion

Study outcomes will determine what dose of baclofen is safe to prescribe to those receiving methadone, to inform a subsequent proof-of-concept trial of the efficacy baclofen to facilitate opiate detoxification. To proceed, the minimum acceptable dose is 30 mg of baclofen in patients receiving ≤ 60 mg/day methadone based on the clinical experience of baclofen’s use in alcoholism and guidelines for the management of opiate dependence.

Trial registration

Clinicaltrials.gov NCT05161351. Registered on 16 December 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06821-9.

Profile of Embedded Validity Indicators in Criminal Defendants with Verified Valid Neuropsychological Test Performance

Objective

Few studies have examined the use of embedded validity indicators (EVIs) in criminal-forensic practice settings, where judgements regarding performance validity can carry severe consequences for the individual and society. This study sought to examine how various EVIs perform in criminal defendant populations, and determine relationships between EVI scores and intrapersonal variables thought to influence performance validity.

Method

Performance on 16 empirically established EVI cutoffs were examined in a sample of 164 criminal defendants with valid performance who were referred for forensic neuropsychological evaluation. Subsequent analyses examined the relationship between EVI scores and intrapersonal variables in 83 of these defendants.

Results

Half of the EVIs (within the Wechsler Adult Intelligence Scale Digit Span Total, Conners’ Continuous Performance Test Commissions, Wechsler Memory Scale Logical Memory I and II, Controlled Oral Word Association Test, Trail Making Test Part B, and Stroop Word and Color) performed as intended in this sample. The EVIs that did not perform as intended were significantly influenced by relevant intrapersonal variables, including below-average intellectual functioning and history of moderate–severe traumatic brain injury and neurodevelopmental disorder.

Conclusions

This study identifies multiple EVIs appropriate for use in criminal-forensic settings. However, based on these findings, practitioners may wish to be selective in choosing and interpreting EVIs for forensic evaluations of criminal court defendants.

Opioid use disorder and the brain: a clinical perspective

Opioid use disorder (OUD) has gained increasing publicity and interest during recent years, with many countries describing problems of epidemic proportions with regard to opioid use and deaths related to opioids. While opioids are not themselves acutely neurotoxic, the chronic relapsing and remitting nature of this disorder means that individuals are often exposed to exogenous opioids for lengthy periods of time (either illicit or prescribed as treatment). We are increasingly characterizing the effect of such long-term opioid exposure on the brain. This narrative review aims to summarize the literature regarding OUD and the brain from a clinical perspective. Alterations of brain structure and function are discussed, as well as neurological and psychiatric disorders in OUD. Finally, we review current and new directions for assessment and treatment.

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.

Pharmacological treatment of pain among persons with opioid addiction: A systematic review and meta-analysis with implications for drug development

The clinical features and neurobiology of pain and opioid use disorder (OUD) are inextricably linked. Despite emerging evidence supporting the negative impact of ongoing pain in the treatment of OUD, the pharmacological management of pain in the presence of OUD has received limited attention. We sought to systematically review the studies investigating pharmacotherapies for pain among persons with OUD. Eligible studies had participants with OUD and outcomes including evoked or spontaneous pain. We searched Scopus, Cochrane Database of Systematic Reviews, Medline, and Embase. Out of 1,097 studies that met the search criteria, 12 studies provided data relevant to the research question-five laboratory studies and seven clinical trials. Random effects pooled estimates suggested no significant difference between groups at baseline but a response favoring the active treatment group over placebo, with nonsignificant heterogeneity between studies. Findings from these studies provide preliminary evidence for analgesic and antihyperalgesic effects of gabapentin, GABA agonists, and NMDA antagonists among persons with OUD. To establish the tradeoffs between the analgesic effects and abuse liability of these compounds, further well-controlled clinical trials are required among persons with OUD. This review also underscores the need for methodological enhancement in drug development for pain in OUD. Future research should address the clinical and neurobiological overlap between pain- and addiction-related phenomena. Transdisciplinary approaches may identify biomarkers of these shared phenomena and their neural substrates. The development of novel therapeutics for pain in OUD may be accelerated by such integration of pain and addiction research.

Evaluation of functional status among patients undergoing maintenance treatments for opioid use disorders

Background

Methadone and buprenorphine are the most prevalent types of opioid maintenance programs in Andalusia. The main objective is comparing the functional status of patients with pharmacological opioid maintenance treatments according to different socio-demographic characteristic, health and disabilities domains and sexual difficulties.

Methods

A total of 593 patients from the Andalusia community, 329 were undergoing methadone treatment and 264 were undergoing buprenorphine treatment. The patients were interviewed by socio-demographic and opioid-related variables, assessed by functioning, disability and health domains (WHODAS 2.0.) and for sexual problems (PRSexDQ-SALSEX).

Results

We found significant differences in the socio-demographic and the opioid-related variables as the onset of opioid use, being on previous maintenance programs, opioid intravenous use, the length of previous maintenance programs, polydrug use and elevated seroprevalence rates (HCV and HIV) between the methadone group and the buprenorphine group. Regarding health and disability domains there were differences in the Understanding and communication domain, Getting around domain, Participation in society domain and in the WHODAS 2.0. simple and complex score, favoring buprenorphine-treated patients. The methadone group referred elevated sexual impairments compared with the buprenorphine group. Opioid-related variables as seroprevalence rates, other previous lifetime maintenance program, the daily opioid dosage and the daily alcohol use are the most discriminative variables between both groups. Participation in society variables and sexual problems were the most important clinical variables in distinguishing the methadone group from the buprenorphine group regarding their functional status.

Conclusions

The methadone group showed higher prevalence in opioid dependence-related variables, elevated disabilities in participation in society activities and sexual problems compared with the buprenorphine group. This study shows the importance of carry out a functional evaluation in the healthcare follow-up, especially in those areas related with social activity and with sexual problems.

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.

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.

Addressing unmet needs in opiate dependence: supporting detoxification and advances in relapse prevention

Despite record-breaking numbers of opiate related deaths in the UK in 2019, pharmacological management of opiate dependence has evolved little since the advent of methadone in 1965. Along with harm minimisation and psychosocial interventions, the mainstay of pharmacological treatment remains opioid substitution therapy (OST) using methadone or buprenorphine, with many patients receiving OST for many years. Even with these treatments, opiate users continue to face mortality risks 12 times higher than the general population, and emerging evidence suggests that individuals who remain on long-term OST present with a range of physical and cognitive impairments. Therefore, with a growing ageing opiate dependent population who would benefit from detoxification from OST, this article provides an overview of the current state of opiate dependence in clinical practice, explores the reasons why availability and acceptability of detoxification pathways are declining, and discusses emerging pharmacological therapies that could provide benefit in relapse prevention.

Does Cannabis Dependence Add on to the Neurocognitive Impairment Among Patients With Opioid Dependence? A Cross-Sectional Comparative Study

BACKGROUND AND OBJECTIVES

Chronic opioid exposure has been linked with neurocognitive impairments. Evidence of residual impairment with cannabis use is less consistent. We investigated whether patients with opioid and cannabis dependence perform poorly compared with those with opioid dependence alone.

METHODS

We recruited three groups of participants aged 18 to 55 years: opioid and cannabis dependence (OCaD; n = 21), only opioid dependence (OD; n = 19), and a control group (HC; n = 20). Subjects with other substance use, human immunodeficiency virus, head injury, epilepsy, and severe mental illness were excluded. Cognitive tests, performed after at least 1 week of abstinence, consisted of the Wisconsin card sorting test (WCST), Iowa gambling task (IGT), trail making tests A and B (TMT-A and B), verbal and visual N-back test (NBT), and standard progressive matrices for intelligence quotient (IQ). The general linear model was used to compare the groups with age and years of education as covariates.

RESULTS

IQ and severity of opioid dependence were comparable in the three groups. The mean duration of cannabis use was 76.2 (±39.4) months. Compared with the HC, both OD and OCaD had significant impairment on the IGT, WCST, TMTs, and NBT. No significant group difference was observed between the OD and OCaD groups.

DISCUSSION AND CONCLUSIONS

Opioid dependence is associated with impairments in decision making, executive function, working memory, and attention. Co-morbid cannabis dependence had similar profiles of cognitive impairments.

SCIENTIFIC SIGNIFICANCE

Co-morbid cannabis dependence might not add on to the existing cognitive dysfunction in opioid dependence. Further studies should be done with a larger sample. (Am J Addict 2020;29:120-128).

Minocycline does not affect experimental pain or addiction-related outcomes in opioid maintained patients

RATIONALE

Minocycline, a tetracycline antibiotic, inhibits activation of microglia. In preclinical studies, minocycline prevented development of opioid tolerance and opioid-induced hyperalgesia (OIH). The goal of this study was to determine if minocycline changes pain threshold and tolerance in individuals with opioid use disorder who are maintained on agonist treatment.

METHODS

In this double-blind, randomized human laboratory study, 20 participants were randomized to either minocycline (200 mg/day) or placebo treatment for 15 days. The study had three test sessions (days 1, 8, and 15 of treatment) and one follow-up visit 1 week after the end of treatment. In each test session, participants were assessed on several subjective and cognitive measures, followed by assessment of pain sensitivity using the Cold Pressor Test (CPT). Daily surveys and cognitive measures using Ecological Momentary Assessment (EMA) were also collected four times a day on days 8 through 14 of treatment, and proinflammatory serum cytokines were assessed before and on the last day of treatment.

RESULTS

Minocycline treatment did not change pain threshold or tolerance on the CPT. Similarly, minocycline did not change severity of pain, opioid craving, withdrawal, or serum cytokines. Minocycline treatment increased accuracy on a Go/No-Go task.

CONCLUSIONS

While these findings do not support minocycline's effects on OIH, minocycline may have a potential use as a cognitive enhancer for individuals with opioid use disorder, a finding that warrants further systematic studies.

Galantamine and Computerized Cognitive Behavioral Therapy for Cocaine Dependence: A Randomized Clinical Trial

OBJECTIVE

To examine whether galantamine, a cognitive-enhancing medication that is both acetylcholinesterase inhibitor and agonist at nicotinic acetylcholine receptors, is effective at improving cocaine use outcomes and cognitive functioning, alone and in combination with computerized cognitive behavioral therapy (CBT).

METHOD

A 12-week, randomized 2 × 2, factorial trial was conducted to evaluate galantamine versus placebo (double-blind) and computerized CBT plus standard methadone treatment versus standard methadone treatment alone in a community-based methadone maintenance program (September 2009-April 2015). One hundred twenty individuals diagnosed with DSM-IV cocaine use disorder were randomly assigned to the following conditions: (1) galantamine (8 mg/d) plus standard methadone maintenance treatment (treatment as usual [TAU]), (2) placebo plus TAU, (3) galantamine plus computerized CBT plus TAU, or (4) placebo plus computerized CBT plus TAU; medication administration was supervised at the time of daily methadone dosing. The primary cocaine use outcome was change in percent days of abstinence over time. Number of cocaine-negative urine toxicology screens submitted and cognitive function were secondary outcomes.

RESULTS

Random effect regression analysis indicated significant reductions in frequency of cocaine use over time, with significant treatment-by-time effects for both galantamine over placebo (F = 5.3, P = .02, d = 0.34) and computerized CBT over standard methadone treatment (F = 4.2, P = .04, d = 0.30) but no evidence of significant benefit of the combination over either treatment alone. Pretreatment to posttreatment comparisons of multiple indices of cognitive functioning, including sustained attention, indicated no benefit of galantamine over placebo.

CONCLUSIONS

Findings suggest benefits of galantamine and computerized CBT for reducing cocaine use in this sample. Although galantamine did not improve measures of cognitive function in this sample, multiple measures of cognitive function were associated with cocaine use outcomes, underlining the significance of cognitive function in cocaine treatment outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00809835.

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.

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.

Pharmacological and Behavioral Treatment of Opioid Use Disorder

Objective:

Opioid use disorder (OUD) in the United States has surged, with an estimated 2.5 million needing treatment. The aim of this article is to provide a clinical overview of the key pharmacological and behavioral treatments for OUD.

Methods:

A nonsystematic review of the literature was conducted to investigate OUD treatments, including their mechanism of action, efficacy, clinical guidelines in the United States, and consideration of frequently occurring comorbid conditions.

Results:

Food and Drug Administration (FDA)–approved pharmacotherapies for OUD include methadone, buprenorphine, and naltrexone, each of which has different actions on opioid receptors. Although these medications all show efficacy in some dosages and formulations, barriers to accessibility may be most pronounced for methadone, whereas treatment retention poses greater challenges for naltrexone and, to a lesser extent, buprenorphine. Lofexidine, an α₂‐adrenergic agonist, has recently been approved by the FDA for treatment of opioid withdrawal symptoms. OUD is commonly treated with medication‐assisted treatment (MAT), which offers pharmacotherapy in the context of counseling and/or behavioral treatments. Behavioral therapies, rarely offered as stand‐alone treatments for OUD, are generally used in the context of MAT, in structured settings or to prevent relapse after detoxification and stabilization. The aim of behavioral interventions is to improve medication compliance and target problems not addressed with medication alone. Individuals with OUD commonly have other comorbid psychiatric and substance use conditions, which are not exclusionary for initiating MAT but should be carefully evaluated and monitored because they may reduce treatment effectiveness.

Conclusions:

MAT is the first‐line treatment for patients with OUD and should be provided in combination with behavioral interventions. Treatment retention remains challenging in this population. Future studies should focus on approaches that will serve the complex needs of patients with OUD, including those with comorbid psychiatric and substance use conditions.

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

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

Compulsivity in opioid dependence

OBJECTIVE

This study aimed to investigate the relationship between compulsivity versus impulsivity and structural MRI abnormalities in opioid dependence.

METHOD

We recruited 146 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=48), iii) abstinent participants with a history of opioid dependence due to heroin use (n=24) and iv) healthy controls (n=50). Compulsivity was measured using Intra/Extra-Dimensional (IED) Task and impulsivity was measured using the Cambridge Gambling Task (CGT). Structural Magnetic Resonance Imaging (MRI) data were also obtained.

RESULTS

As hypothesised, compulsivity was negatively associated with impulsivity (p<0.02). Testing for the neural substrates of compulsivity versus impulsivity, we found a higher compulsivity/impulsivity ratio associated with significantly decreased white matter adjacent to the nucleus accumbens, bed nucleus of stria terminalis and rostral cingulate in the abstinent group, compared to the other opioid dependent groups. In addition, self-reported duration of opioid exposure correlated negatively with bilateral globus pallidus grey matter reductions.

CONCLUSION

Our findings are consistent with Volkow & Koob's addiction models and underline the important role of compulsivity versus impulsivity in opioid dependence. Our results have implications for the treatment of opioid dependence supporting the assertion of different behavioural and biological phenotypes in the opioid dependence and abstinence syndromes.

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

RATIONALE

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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