Neuropsychological consequences of chronic opioid use: A quantitative review and meta-analysis

Increased risky choice during forced abstinence from fentanyl on the cued rat gambling task

RATIONALE

The use of illicit opioids has arguably never been more risky; street drug potency can be dangerously high, is often unknown to the consumer, and results in multiple daily fatalities worldwide. Furthermore, substance use disorder (SUD) is associated with increased maladaptive, risky decisions in laboratory-based gambling tasks. Animal studies can help determine whether this decision-making deficit is a cause or consequence of drug use. However, most experiments have only assessed psychostimulant drugs.

OBJECTIVES

To assess differences in decision-making strategies both before, during, and after self-administration of fentanyl in male and female Long Evans rats.

METHODS

Male and female Long Evans rats were trained to perform the rat gambling task (rGT), loosely based on the Iowa Gambling Task (IGT) used clinically, and/or self-administer fentanyl. We used the cued version of the rGT, in which sound and light stimuli signal sugar pellet rewards, as cocaine self-administration has the greatest effects on decision making in this task variant.

RESULTS

After training on the cued rGT, female rats self-administered fentanyl more readily, an effect that was most apparent in optimal decision-makers. Contrary to previous reports using cocaine self-administration, decision-making was unaffected during fentanyl self-administration training in either sex. However, risky decision-making increased throughout forced abstinence from fentanyl in males.

CONCLUSIONS

These findings complement those from human subjects, in whom preference for uncertain outcomes increased before relapse. These data highlight an abstinence-induced change in cognition that is unique to opiates as compared to psychostimulants, and which may critically contribute to the maintenance of addiction and relapse.

Neural correlates of metacognition impairment in opioid addiction

BACKGROUND

Individuals with substance use disorder show impaired self-awareness of ongoing behavior. This deficit suggests problems with metacognition, operationalized in the cognitive neuroscience literature as the ability to monitor and evaluate the success of one's own cognition and behavior. However, the neural mechanisms of metacognition have not been characterized in a drug-addicted population.

METHODS

Community samples of participants with opioid use disorder (OUD) (N=27) and healthy controls (N=29) performed a previously-validated fMRI metacognition task (perceptual decision-making task along with confidence ratings of performance). Measures of recent drug use and addiction severity were also acquired.

RESULTS

Individuals with OUD had lower metacognitive sensitivity than controls (i.e., disconnection between task performance and task-related confidence). Trial-by-trial analyses showed that this overall group difference was driven by (suboptimally) low confidence in OUD during correct trials. In fMRI analyses, the task engaged an expected network of brain regions (e.g., rostrolateral prefrontal cortex and dorsal anterior cingulate/supplementary motor area, both previously linked to metacognition); group differences emerged in a large ventral anterior cluster that included the medial and lateral orbitofrontal cortex and striatum (higher activation in OUD). Trial-by-trial fMRI analyses showed group differences in rostrolateral prefrontal cortex activation, which further correlated with metacognitive behavior across all participants. Exploratory analyses suggested that the behavioral and neural group differences were exacerbated by recent illicit opioid use and unexplained by general cognition.

CONCLUSIONS

With confirmation and extension of these findings, metacognition and its associated neural circuits could become new, promising therapeutic targets in addiction.

Impulsiveness, suicide, and aggression in a sample of patients with disorders of methyl amphetamine use

BACKGROUND

Research has showed a link between patients with methamphetamine dependence and the risk of impulsiveness, aggression, and the risk of suicide. But, this link has not been studied in patients abusing methamphetamine, and it is unknown how impulsiveness, aggression, and the risk of suicide affect them.

MATERIALS AND METHODS

This cross-sectional study included 130 adult patients diagnosed with the disorder of the use of amphetamine, methamphetamine, cannabinoids, alcohol, other substances, and polysubstance admitted in the Addiction Department for Mental Health. Participants were interviewed for detailed psychiatric history using a structured questionnaire comprising of structured clinical interview for diagnosis I, Arabic version of the Barratt Impulsiveness Scale-11 (BIS), Beck Scale for Suicidal Ideation for the evaluation of suicidal ideation and behavior, and the Aggression and Hostility scale for adolescents and youth. SPSS was used for data analysis; Initial analysis included descriptive statistics: frequencies and percentages for categorical variables and mean and standard deviation for continuous variables. Chi-square test/Fisher's exact test assessed for association between categorical variables, whereas one-way analysis of variance (ANOVA)/ Kruskal-Wallis test was used to compare continuous variables.

RESULTS

Patients who used methamphetamine either alone (23%) or with polysubstance (42.6%) were associated with higher suicidal risk than patients who did use other substances than methamphetamine (36.1%). A comparison of the three groups on impulsivity, showed significant difference regarding total scores, motor preservation, and non-planning self-control. No significant differences found between three groups on the aggression scores.

CONCLUSIONS

There was a higher rate of impulsivity and suicidal risk in patients with methamphetamine dependence in comparison to dependence on other substances, while there was no difference with regard to aggression between patients with methamphetamine dependence and those dependent on other substances. This finding raises the issue of methamphetamine use disorder as a new substance of dependence.

Opioid modulation of prefrontal cortex cells and circuits

Several neurochemical systems converge in the prefrontal cortex (PFC) to regulate cognitive and motivated behaviors. A rich network of endogenous opioid peptides and receptors spans multiple PFC cell types and circuits, and this extensive opioid system has emerged as a key substrate underlying reward, motivation, affective behaviors, and adaptations to stress. Here, we review the current evidence for dysregulated cortical opioid signaling in the pathogenesis of psychiatric disorders. We begin by providing an introduction to the basic anatomy and function of the cortical opioid system, followed by a discussion of endogenous and exogenous opioid modulation of PFC function at the behavioral, cellular, and synaptic level. Finally, we highlight the therapeutic potential of endogenous opioid targets in the treatment of psychiatric disorders, synthesizing clinical reports of altered opioid peptide and receptor expression and activity in human patients and summarizing new developments in opioid-based medications. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".

Revive and Refuse: Capacity, Autonomy, and Refusal of Care After Opioid Overdose

Physicians generally recommend that patients resuscitated with naloxone after opioid overdose stay in the emergency department for a period of observation in order to prevent harm from delayed sequelae of opioid toxicity. Patients frequently refuse this period of observation despiteenefit to risk. Healthcare providers are thus confronted with the challenge of how best to protect the patient's interests while also respecting autonomy, including assessing whether the patient is making an autonomous choice to refuse care. Previous studies have shown that physicians have widely divergent approaches to navigating these conflicts. This paper reviews what is known about the effects of opioid use disorder on decision-making, and argues that some subset of these refusals are non-autonomous choices, even when patients appear to have decision making capacity. This conclusion has several implications for how physicians assess and respond to patients refusing medical recommendations after naloxone resuscitation.

"Everything is kind of the same except my mind is with me": exploring cannabis substitution in a sample of adults in early recovery from an opioid or stimulant addiction

BACKGROUND

Recovery from addiction is frequently equated with abstinence. However, some individuals who resolve an addiction continue to use substances, including via substitution (i.e., increased use of one substance after eliminating/ reducing another). Substitution may play a distinct role during early recovery (≤ 1 year), as this period is marked by dramatic change and adjustment. Cannabis is one of the most used substances and is legal for medical and recreational use in an increasing number of states. Consequently, cannabis an increasingly accessible substitute for substances, like fentanyl, heroin, cocaine and methamphetamine, with higher risk profiles (e.g., associated with risk for withdrawal, overdose, and incarceration).

METHODS

Fourteen participants reported that they had resolved a primary opioid or stimulant addiction and subsequently increased their cannabis use within the previous 12 months. Using grounded theory, the interviewer explored their experiences of cannabis use during early recovery. Data were analyzed in three stages: line by line coding for all text related to cannabis use and recovery, focused coding, and axial coding to generate a theory about recovery with cannabis substitution. The motivational model of substance use provided sensitizing concepts.

RESULTS & DISCUSSION

The final sample included eight men and six women ranging in age from 20 to 50 years old. Three participants resolved an addiction to methamphetamine and the remaining 11, an addiction to opioids. Participants explained that cannabis was appealing because of its less harmful profile (e.g., no overdose risk, safe supply, few side effects). Participants' primary motives for cannabis use included mitigation of psychiatric symptoms, withdrawal/ cravings, and boredom. While cannabis was effective toward these ends, participants also reported some negative side effects (e.g., decreased productivity, social anxiety). All participants described typical benefits of recovery (e.g., improved self-concept, better relationships) while continuing to use cannabis. Their experiences with and beliefs about substitution suggest it can be an effective strategy for some individuals during early recovery.

CONCLUSIONS

Cannabis use may benefit some adults who are reducing their opioid or stimulant use, especially during early recovery. The addiction field's focus on abstinence has limited our knowledge about non-abstinent recovery. Longitudinal studies are needed to understand the nature of substitution and its impact on recovery over time.

Transcranial direct current stimulation combined with cognitive training improves decision making and executive functions in opioid use disorder: a triple-blind sham-controlled pilot study

Opioid use disorder (OUD) is a chronic disorder with a considerable amount of morbidity and mortality. Despite remarkable improvement achieved by maintenance programs, an array of treatment goals were still unmet. Mounting evidence suggests that transcranial Direct Current Stimulation (tDCS) improves decision making and cognitive functions in addictive disorders. tDCS paired with a decision making task was depicted to diminish impulsivity as well.

The present study aimed to assess the effect of tDCS combined with cognitive training (CT) in OUD for the first time.

In this triple-blind randomized sham-controlled pilot study, 38 individuals with OUD from the Buprenorphine-Naloxone Maintenance Therapy program were administered 20-minutes of 2 mA active/sham tDCS over the dorsolateral prefrontal cortex with concomitant cognitive training. A selected test battery evaluating decision making under risk and ambiguity as well as executive functions, verbal fluency and working memory was utilized before and after the intervention.

Greater improvements were observed in decision making under ambiguity (p = 0.016), set shifting ability and alternating fluency while no improvements were observed in decision making under risk in the active group, compared to sham.

Deficits of decision making and executive functions have a pivotal role in the perpetuation and the relapse of the OUD. Alleviation of these impairments brought tDCS/CT forth as an expedient neuroscientifically-grounded treatment option that merits further exploration in OUD, Trial registration: NCT05568251.

Genome-wide analyses reveal shared genetic architecture and novel risk loci between opioid use disorder and general cognitive ability

BACKGROUND

Opioid use disorder (OUD), a serious health burden worldwide, is associated with lower cognitive function. Recent studies have demonstrated a negative genetic correlation between OUD and general cognitive ability (COG), indicating a shared genetic basis. However, the specific genetic variants involved, and the underlying molecular mechanisms remain poorly understood. Here, we aimed to quantify and identify the genetic basis underlying OUD and COG.

METHODS

We quantified the extent of genetic overlap between OUD and COG using a bivariate causal mixture model (MiXeR) and identified specific genetic loci applying conditional/conjunctional FDR. Finally, we investigated biological function and expression of implicated genes using available resources.

RESULTS

We estimated that ~94% of OUD variants (4.8k out of 5.1k variants) also influence COG. We identified three novel OUD risk loci and one locus shared between OUD and COG. Loci identified implicated biological substrates in the basal ganglia.

CONCLUSION

We provide new insights into the complex genetic risk architecture of OUD and its genetic relationship with COG.

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.

Compulsivity and Inhibitory Control Deficits in Abstinent Individuals With Heroin Addiction and Their Biological Siblings Compared With Unrelated Healthy Control Participants

BACKGROUND

Compulsivity represents the performance of persistent and repetitive acts despite negative consequences and is considered one of the critical mechanisms for drug addiction. Although compulsivity-related neurocognitive impairments have been linked to addiction, it remains unclear whether these deficits might have predated drug abuse as potential familial susceptibilities.

METHODS

A large sample of 213 adult participants were recruited, including 70 abstinent individuals addicted to heroin (HAs), 69 unaffected biological siblings of the HAs (siblings), and 74 unrelated healthy control participants. Compulsivity-related neurocognitive functions were evaluated using the intradimensional/extradimensional set-shift task and a probabilistic reversal learning task. Compulsive traits were measured by the Obsessive-Compulsive Inventory-Revised. Inhibitory control was assessed using the stop signal task and Stroop Color and Word Test. Network models for group recognition were conducted using multilayer perceptron neural networks.

RESULTS

Data indicated that both HAs and siblings performed worse than healthy control participants on compulsivity-related aspects (i.e., shifting and reversal learning functions) and inhibitory control and had higher levels of self-reported compulsive traits. Furthermore, neural models revealed that a possible 3-facet clustering of neurocognitive deficits was linked to both HAs and siblings.

CONCLUSIONS

Our findings suggest that deficits in shift reversal and inhibitory control aspects and elevated compulsive traits, shared by HAs and their unaffected siblings, may putatively represent conceivable markers associated with familial vulnerabilities implicated in the development of heroin dependence.

Neurocognitive Dysfunctions in People with Concurrent Cannabis Use and Opioid Dependence: A Cross-Sectional, Controlled Study

Cannabis and opioid co-dependence is independently associated with cognitive impairments. We examined neurocognitive dysfunctions in people with concurrent opioid dependence with cannabis dependence (OD+CD) or cannabis use (OD+CU) compared to those with only opioid dependence (OD) and healthy controls (HC). We selected adult participants, any sex, who met the diagnosis of OD (N = 268), OD+CU (N = 58), and OD + CD (N = 115). We recruited 68 education-matched HC. We administeredStandard progressive matrices (SPM), Wisconsin card sorting test (WCST), Iowa gambling task (IGT), Trail making tests A and B (TMT), and verbal and visual working memory 1-, 2-backtests. 496 (97.5%) were men, and 13 (2.5%) were women. In WCST, OD and OD+CD had significantly higher non-perseverative errors than HC. OD+CD group completed significantly lesser categories than HC. In verbal working memory 2-back, HC scored significantly fewer errors than OD and OD +CD. All patient groups, OD, OD+CU, and OD+CD, scored higher commission errors than HC in visual working memory 1-back. OD and OD+CD scored higher commission and total errors than the controls. OD+CU showed lesser error score than HC in TMT B. Cannabis and opioid co-dependence contribute to cognitive impairments, especially in working memory and executive functions.

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.

Effects of fentanyl self-administration on risk-taking behavior in male rats

RATIONALE

Individuals with opioid use disorder (OUD) exhibit impaired decision making and elevated risk-taking behavior. In contrast to the effects of natural and semi-synthetic opioids, however, the impact of synthetic opioids on decision making is still unknown.

OBJECTIVES

The objective of the current study was to determine how chronic exposure to the synthetic opioid fentanyl alters risk-based decision making in adult male rats.

METHODS

Male rats underwent 14 days of intravenous fentanyl or oral sucrose self-administration. After 3 weeks of abstinence, rats were tested in a decision-making task in which they chose between a small, safe food reward and a large food reward accompanied by variable risk of footshock punishment. Following testing in the decision-making task, rats were tested in control assays that assessed willingness to work for food and shock reactivity. Lastly, rats were tested on a probabilistic reversal learning task to evaluate enduring effects of fentanyl on behavioral flexibility.

RESULTS

Relative to rats in the sucrose group, rats in the fentanyl group displayed greater choice of the large, risky reward (risk taking), an effect that was present as long as 7 weeks into abstinence. This increased risk taking was driven by enhanced sensitivity to the large rewards and diminished sensitivity to punishment. The fentanyl-induced elevation in risk taking was not accompanied by alterations in food motivation or shock reactivity or impairments in behavioral flexibility.

CONCLUSIONS

Results from the current study reveal that the synthetic opioid fentanyl leads to long-lasting increases in risk taking in male rats. Future experiments will extend this work to females and identify neural mechanisms that underlie these drug-induced changes in risk taking.

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.

Regaining control over opioid use? The potential application of auricular transcutaneous vagus nerve stimulation to improve opioid treatment in China

Opioid use disorder (OUD) is a critical problem in China and is accompanied by depression and deficits in cognitive control. In China, the most successful intervention for OUD is the community drug rehabilitation where methadone maintenance treatment (MMT) plays a key role. Even though methadone for the treatment of OUD can be helpful, it can cause severe somatic side-effects, which limit its effectivity. Even worse, it can have detrimental effects on cognitive control, which is crucial to regain control over drug intake. Here, we consider the potential use of auricular transcutaneous vagus nerve stimulation (atVNS) as an addition to MMT for opioid withdrawal treatment. Compared to other non-invasive brain stimulation methods, atVNS also targets the locus coeruleus (LC) important for noradrenaline (NA) synthesis. NA is an essential neurotransmitter impacted in opioid withdrawal and also critically involved in cognitive control processes. Its ADD-ON to MMT might be a useful mean to improve mood and enhance cognitive control processes impacted in OUD. We discuss the translational advantages of atVNS in China such as the cultural acceptance of the modality of treatment similar to electroacupuncture. Additionally, the wearability of the ear electrode and at-home self-administration without intense medical supervision makes of atVNS a useful tool to enhance clinical and cognitive outcomes especially in everyday life situation. We discuss how atVNS can be integrated in tele-medical health approaches allowing that innovative treatments can widely be disseminated and continued even in situations of restricted medical access.

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.

Cognitive impairment in opioid use disorders: Is there a case for use of nootropics?

Opioid Use Disorders (OUDs) are often associated with cognitive impairments, which may lead to an increased risk of relapse. These cognitive deficits do not resolve with abstinence or medication-assisted treatment and may require targeted management. While psychotherapies and neuromodulation techniques have been studied for their effectiveness, they have certain limitations and challenges. Cognition enhancing prescription drugs like donepezil and memantine, which are used in dementias, have shown promise in a small number of studies examining their role in the reversal of opioid-induced cognitive deficits. The authors explore the potential role of nootropics in improvement of cognitive decline associated with OUDs.

Investigating anabolic-androgenic steroid dependence and muscle dysmorphia with network analysis among male weightlifters

BACKGROUND

Anabolic-androgenic steroid (AAS) dependence has numerous adverse health consequences, and may be driven in part by body image concerns, primarily muscle dysmorphia. This study aims to further understand and identify potential clinical targets using network analyses of AAS dependence and muscle dysmorphia symptoms in males who used AAS and weightlifting controls.

METHODS

A sample of 153 men who currently or previously used AAS and 88 weight-lifting controls were recruited through social media and relevant online forums, and via posters and flyers distributed in select gyms in Oslo, Norway. Symptoms of AAS dependence and muscle dysmorphia were assessed using clinical interviews and standardized questionnaires. Severity of muscle dysmorphia symptoms were compared between the groups using independent samples t-tests. The following symptom networks were computed using Gaussian graphical modeling or mixed graphical modeling: (1) AAS dependence symptoms among men with AAS use (2) muscle dysmorphia symptoms among men with AAS use and weight-lifting controls in two separate networks, which were compared using a network comparison test, and (3) AAS dependence and muscle dysmorphia symptoms among men with AAS use.

RESULTS

In a network of AAS dependence symptoms, continuing use despite physical and mental side effects, using longer than planned, tolerance, and work/life interference were the most central symptoms. When comparing symptom structures of muscle dysmorphia between those who used AAS and controls, the most central symptoms in each group were exercise dependence and size/symmetry concerns, respectively. Men with AAS use demonstrated elevated muscle dysmorphia symptoms compared to controls, indicating that both the severity and structure of symptoms differ between these groups. In a network including both AAS dependence and muscle dysmorphia symptoms, no significant connections between symptom groups were identified.

CONCLUSIONS

AAS dependence is complex, with correlated somatic and psychological challenges driving the symptom network, indicating that alleviating physical and mental health concerns during both AAS use and cessation is an important clinical target. Muscle dysmorphia symptoms related to taking action (diet, exercise, and supplement use) appear to cluster together more for those who use AAS than those who do not.

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.

Heroin use and neuropsychological impairments: comparison of intravenous and inhalational use

BACKGROUND AND OBJECTIVES

Injection and inhalational heroin use are associated with different levels of brain exposure to heroin and its metabolites and differences in the severity of dependence, which might lead to differential impacts on neuropsychological functions. We examined the difference and the magnitude of difference in the neuropsychological functions between inhalational and injection heroin-dependent subjects and also compared them with healthy controls.

METHODS

The study sample comprised three groups: 73 subjects with injection heroin dependence, 74 with inhalational heroin dependence, and 75 healthy controls (HC). We excluded patients with HIV, head injury, epilepsy, and severe mental illness. Neuropsychological assessments were done by Standard Progressive Matrices, Wisconsin Card Sorting Test (WCST), Iowa Gambling Task, Trail-Making Tests A and B (TMT), and Verbal and Visual Memory 1 and 2 Backtests (NBT). We estimated independent effects of the groups on various neuropsychological test parameters, adjusted for age and duration of dependence.

RESULTS

In the WCST, the inhalational heroin-dependent group took more trials to complete the first category and had higher scores in the failure to maintain set than controls. The intravenous group had higher total errors than controls in verbal working memory tests and Visual Working Memory 2 Backtest. This group scored higher commission errors in the Verbal 2 Backtest than the controls. The two groups of heroin users differed in failure to maintain set and Verbal Working Memory 2 Backtests. The effect sizes of the group differences were modest.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Either route of heroin use is associated with cognitive impairments; inhalational and injection use involve different cognitive domains.

Neurocognitive Functions in Patients with Comorbid Hepatitis C and Opioid Dependence: A Comparative Study

Background

Hepatitis C virus (HCV) infection is commonly comorbid with opioid dependence (OD). We wanted to compare the neurocognitive functions of OD subjects with or without HCV [HCV (+), HCV (-)] and healthy controls (HC).

Methods

We recruited 40 adult subjects (age 18-55 years) in each group. HCV(+) group had a detectable viral load. Subjects with HIV or hepatitis B infection, head injury, epilepsy, or comorbid mental illness were excluded. We administered Standard Progressive Matrices (SPM), Wisconsin Card Sorting Test, Iowa Gambling Task (IGT), trail-making tests A and B, and verbal and visual N-back tests (NBT) one week after opioid abstinence. The group differences in cognitive performance were adjusted for age and years of education. Effect size (ES) is expressed as Cohen's D.

Results

The HCV(+) and HCV(-) groups did not differ in potential effect modifiers (age and years of education) or confounders (age of opioid initiation, duration of use, dependence severity, tobacco use, and cannabis use) of neuropsychological functioning. HCV(+) showed significantly poorer performance than HCV(-) in SPM (P = 0.006; ES = 0.72). Both HCV(+) and HCV(-) performed worse than controls in IGT(P < 0.001; ES = 0.8) and visual NBT[P < 0.01 and ES > 1 for total errors]; HCV(+) had a larger ES of group difference than HCV(-). HCV(+) had higher error scores in verbal NBT than control.

Conclusion

HCV(+) has poorer general intellectual ability and reasoning than HCV(-) persons and controls. Chronic HCV infection causes a higher magnitude of dysfunction in decision-making and visual working memory in opioid-dependent individuals.

Impact of preexisting opioid dependence on morbidity, length of stay, and inpatient cost of urological oncological surgery

OBJECTIVES

To determine the incidence of preexisting opioid dependence in patients undergoing elective urological oncological surgery. In addition, to quantify the impact of preexisting opioid dependence on outcomes and cost of common urologic oncological procedures at a national level in the USA.

METHODS

We used the National Inpatient Sample (NIS) to study 1,609,948 admissions for elective partial/radical nephrectomy, radical prostatectomy, and cystectomy procedures. Trends of preexisting opioid dependence were studied over 2003-2014. We use multivariable-adjusted analysis to compare opioid-dependent patients to those without opioid dependence (reference group) in terms of outcomes, namely major complications, length of stay (LOS), and total cost.

RESULTS

The incidence of opioid dependence steadily increased from 0.6 per 1000 patients in 2003 to 2 per 1000 in 2014. Opioid-dependent patients had a significantly higher rate of major complications (18 vs 10%; p < 0.001) and longer LOS (4 days (IQR 2-7) vs 2 days (IQR 1-4); p < 0.001), when compared to the non-opioid-dependent counterparts. Opioid dependence also increased the overall cost by 48% (adjusted median cost $18,290 [IQR 12,549-27,715] vs. $12,383 [IQR 9225-17,494] in non-opioid-dependent, p < 0.001). Multivariable analysis confirmed the independent association of preexisting opioid dependence with major complications, length of stay in 4th quartile, and total cost in 4th quartile.

CONCLUSIONS

The incidence of preexisting opioid dependence before elective urological oncology is increasing and is associated with adverse outcomes after surgery. There is a need to further understand the challenges associated with opioid dependence before surgery and identify and optimize these patients to improve outcomes.

Neurocognitive Impulsivity in Opiate Users at Different Lengths of Abstinence

The aim of the current study was to examine the effects of length of abstinence on decision making (impulsive choice) and response inhibition (impulsive action) in former opiate users (OU). Participants included 45 OU in early remission [0−12 months of abstinence], 68 OU in sustained remission [>12 months of abstinence], and 68 control participants. Decision making was assessed with the Iowa Gambling Task (IGT), the Cambridge Gambling Task (CGT), and the Monetary Choice Questionnaire (MCQ). Response inhibition was examined with the Stop Signal Task (SST), and the Go/No-Go Task (GNG). Results revealed group differences in decision making under risk (CGT) and ambiguity (IGT), where control participants displayed better decision making compared to OU in early remission. Both groups of former OU were also characterized by higher discounting of delayed rewards (MCQ). Regression analyses revealed minimal effects of length of abstinence on performance on decision-making tasks and no effects on delay discounting. In addition, both OU groups showed reduced action inhibition (GNG) relative to controls and there were no group differences in action cancellation (SST). Length of abstinence had no effect on response inhibition. Overall, our findings suggest that neurocognitive function may not fully recover even with protracted abstinence, which should be addressed by relapse prevention and cognitive remediation programs for OU.

Evaluating the temporal association between the recency of prescribed controlled substance acquisition and fatal and non-fatal opioid overdose

BACKGROUND

Previous studies have explored psychosocial effects as possible triggers of opioid overdose (OOD). However, little is known about the temporal association between OOD and prescribed controlled substance (CS) acquisition.

OBJECTIVE

The objective of this study was to evaluate the temporal relationship between OOD and acquiring prescribed CSs prior to OOD.

METHODS

This study is an exploratory descriptive analysis using Arkansas Prescription Drug Monitoring Program (AR-PDMP) data linked to death certificate and statewide inpatient discharge records. All persons with ≥1 AR-PDMP prescription fill(s) between 1 January 2014 and 31 December 2017 were included (n = 1,946,686). For persons that experienced OOD and had ≥1 PDMP record(s), the difference in days between OOD and the most recent AR-PDMP prescription filled prior to an OOD was recorded. To account for censoring, a sensitivity analysis was conducted restricting the study group to "New AR-PDMP Entrants" that had at least a 180-day gap between consecutive AR-PDMP fill dates.

RESULTS

28,998,307 AR-PDMP records were analyzed for 1,946,686 individuals. 7195 persons experienced 9223 OODs and 414 (4.49%) of those were fatal. Of these, 6236 experienced ≥1 OOD and acquired prescribed CSs prior to or on the day of the first OOD. Of those that experienced ≥1 OOD(s), 2201 (30.59%) had an AR-PDMP record in the 0- to 5-day period prior to their overdose and 497 (6.91%) had an AR-PDMP record the day prior to their overdose. Among New AR-PDMP Entrants that experienced ≥1 OOD(s), 408 (27.38%) had an AR-PDMP record in the 0- to 5-day period prior to their overdose.

CONCLUSION

Though the vast majority of persons accessing CSs in Arkansas did not experience an OOD, a sizable proportion of persons that experience an OOD(s) obtained prescribed CSs immediately prior.

The subjective experience of heroin effects among individuals with chronic opioid use: Revisiting reinforcement in an exploratory study

Aims

Consistent with the opponent process theory individuals with chronic opioid use should predominantly endorse the avoidance of aversive negative emotional and/or physiological states as the motivation for continued opioid use (source of reinforcement: reductions in negative states). The primary aim of this study was to explore whether this view is supported by the subjective effects of heroin reported by individuals with opioid use disorder (OUD).

Methods

Responses during in-person interviews of participants to the question "What do you like about heroin? " were categorized as positive, negative, or mixed (positive and negative) reinforcement. In addition, we examined differences between these "reinforcement groups" in sociodemographic and clinical variables.

Results

Participants (N = 307) with OUD were predominantly male (78.1%), with chronic heroin use (M = 15.8 years, SD = 11.5), and 46.1% currently used heroin and were not enrolled in treatment. Agreement between two raters concerning the categorization of participant-reported effects of heroin into reinforcement categories was high, κ= 0.924, p < .0005. Approximately half (49.8%) of participant-reported effects of heroin were categorized as attributable to positive reinforcement. About one-fourth (22.8%) were categorized as negative reinforcement and 9.0% as "mixed ". There were no statistically significant differences between the three reinforcement groups in any of the socio-demographic variables, duration of heroin use, or treatment status/interest.

Conclusions

The results of this study indicate marked heterogeneity of heroin effects experienced by individuals with OUD and their source of reinforcement, respectively. Better integration of how individuals construe their drug use is important to understand the psychological-and neurobiological-processes in the development and maintenance of OUD.

Quality of Life and Opioid Use Motives: Direct and Indirect Associations with Risky Opioid Use in a Community Sample of Adults

Purpose: The opioid epidemic in the United States has resulted in mass mortality and economic costs exceeding $1 trillion. Poor health-related quality of life is evident among individuals entering treatment for opioid use disorder (OUD). Yet, little research has examined the influence of quality of life on risky opioid use among non-treatment-seeking adults. To help inform OUD prevention efforts, this study examined the association among quality of life domains, opioid use motives, and risky opioid behaviors in a community sample of opioid users. Methods: Participants (N = 278) were adults who endorsed past month opioid use and were not currently in treatment for OUD. Participants responded to questions regarding their opioid use and misuse, opioid use motives, opioid use consequences, and quality of life. Results: The physical health domain of quality of life was associated with risky opioid use. Specifically, poorer physical health predicted risky opioid use and this relationship was partially explained by more social and pain motives to use opioids. Surprisingly, no other quality of life domains predicted risky opioid use. Conclusion: This study represents a meaningful first step in identifying optimal targets for OUD prevention efforts with community samples. Our findings suggest that physical health is an important quality of life indicator to prevent opioid-related harm and development of OUD.

Association Between Inflammatory Cytokines, Executive Function, and Substance Use in Patients With Opioid Use Disorder and Amphetamine-Type Stimulants Use Disorder

BACKGROUND

Long-term opioid and amphetamine-type stimulants (ATS) abuse may affect immunological function and impair executive function. We aimed to determine whether biomarkers of inflammation and executive function were associated with substance use in individuals with opioid use disorder (OUD) and ATS use disorder (ATSUD). The interactions between these biomarkers were also explored.

METHODS

We assessed plasma cytokines [tumor necrosis factor (TNF)-α, C-reactive protein (CRP), interleukin (IL)-8, IL-6, transforming growth factor (TGF)-β1, brain-derived neurotrophic factor (BDNF), and executive function in terms of the Wisconsin Card Sorting Test (WCST) and Continuous Performance Test (CPT) in OUD and ATSUD patients and healthy controls (HC). OUD and ATSUD patients were followed for 12 weeks, and their urine morphine and amphetamine tests, cytokine levels, and executive function were repeatedly measured.

RESULTS

We enrolled 483 patients and 145 HC. Plasma TNF-α, CRP, IL-8, IL-6, and BDNF levels and most subscale scores on the WCST and CPT significantly differed between OUD and ATSUD patients and HC. Increased TNF-α levels and more perseveration error on the WCST were significantly associated with more urine drug-positive results and less abstinence. Plasma IL-6 and CRP levels were significantly negatively correlated with WCST and CPT performance.

CONCLUSION

OUD and ATSUD patients had more inflammation and worse executive function than HC. Inflammatory markers and WCST performance were associated with their urinary drug results, and higher inflammation was associated with poor executive function. Studies on regulating the inflammatory process and enhancing executive function in OUD and ATSUD are warranted.

Case Report: De Novo and Persistent Psychosis After Withdrawal From Chronic Opioid Therapy

Psychiatric illness is associated with both chronic pain syndromes and opioid use disorder, further complicating how we care for patients with psychiatric issues. We report a unique case of a de novo and persistent psychotic disorder after complicated opioid withdrawal in a patient without any psychiatric history. The patient developed persistent auditory hallucinations after discontinuation of chronic opioid therapy that responded only to atypical antipsychotic (olanzapine) treatment. This case illustrates the neuropsychiatric effects of chronic opioid exposure, as well as layered clinical management dimensions related to opioid detoxification and psychosis treatment. Long-term opioid therapy may have lasting neuropsychiatric effects, including playing a role in the development and/or expression of psychotic disorders. Here we review the limited literature on the effects of opioids on psychosis. This complex case also demonstrates a clinical approach for effectively co-managing psychiatric symptoms in the context of chronic pain and chronic opioid therapy.

Inflammatory, oxidative stress and cognitive functions in patients under maintenance treatment with methadone or buprenorphine and healthy subjects

BACKGROUND

Methadone and buprenorphine which are widely used for opioid maintenance treatment can affect redox status and also brain functions. The present study aimed to compare inflammation, oxidative stress, and cognitive function in methadone maintenance patients (MMP), buprenorphine maintenance patients (BMP), and healthy participants.

METHOD

Oxidative- antioxidant markers, inflammatory factors were investigated in MMP (n = 30), BMP (n = 30), and healthy participants (n = 30) by evaluating the ferritin, malondialdehyde (MDA), total antioxidant capacity (TAC), and also High-sensitivity C-reactive protein (hs-CRP). Also, executive function was evaluated using Wisconsin Card Sorting Test (WCST).

FINDINGS

MMP and BMP showed impairment in executive function compared to the healthy participants. Both buprenorphine and methadone treatments induced oxidative stress. The ferritin level in BMP was significantly lower compared to MMP and healthy participants (P = 0.01). There was a significant difference between control and MMP and BMP (P > 0.0001) in terms of hs-CRP level. BMP had the highest and healthy participant's lowest MDA level (P < 0.001). The TAC levels in BMP were lower than in MMP (p = 0.002) and healthy participants (p = 0.001). Finally, executive function was significantly correlated with oxidative-antioxidant status.

DISCUSSION

Both methadone and buprenorphine induced severe oxidative activity (especially buprenorphine) and cognitive deficits compared to healthy participants. Stress oxidative can affect normal brain activity and consequently cognitive functions. It's suggested that concomitant antioxidant administration with buprenorphine or methadone can potentially enhance their beneficial action by regulating blood redox status.

Resting-state EEG, Substance use and Abstinence After Chronic use: A Systematic Review

Resting-state EEG reflects intrinsic brain activity and its alteration represents changes in cognition that are related to neuropathology. Thereby, it provides a way of revealing the neurocognitive mechanisms underpinning chronic substance use. In addition, it is documented that some neurocognitive functions can recover following sustained abstinence. We present a systematic review to synthesize how chronic substance use is associated with resting-state EEG alterations and whether these spontaneously recover from abstinence. A literature search in Medline, PsycINFO, Embase, CINAHL, Web of Science, and Scopus resulted in 4088 articles, of which 57 were included for evaluation. It covered the substance of alcohol (18), tobacco (14), cannabis (8), cocaine (6), opioids (4), methamphetamine (4), and ecstasy (4). EEG analysis methods included spectral power, functional connectivity, and network analyses. It was found that long-term substance use with or without substance use disorder diagnosis was associated with broad intrinsic neural activity alterations, which were usually expressed as neural hyperactivation and decreased neural communication between brain regions. Some studies found the use of alcohol, tobacco, cocaine, cannabis, and methamphetamine was positively correlated with these changes. These alterations can partly recover from abstinence, which differed between drugs and may reflect their neurotoxic degree. Moderating factors that may explain results inconsistency are discussed. In sum, resting-state EEG may act as a potential biomarker of neurotoxic effects of chronic substance use. Recovery effects awaits replication in larger samples with prolonged abstinence. Balanced sex ratio, enlarged sample size, advanced EEG analysis methods, and transparent reporting are recommended for future studies.

Do opioid prescriptions lead to fatal car crashes?

Widespread opioid misuse suggests a potential for increased fatal car crashes. However, opioid use may not necessarily lead to additional crashes if drivers respond to opioid prevalence by substituting away from more inebriating intoxicants like alcohol. Combining data on local opioid prescription rates and car crashes from the Fatality Analysis and Reporting System, we use two-way fixed effects models to test the direction of the association between prescribing intensity and crash fatalities between 2007 and 2016. We estimate that a 10 percent increase in the local prescription rate is associated with a 1 percent increase in the number of driver deaths in motor vehicle accidents. The association is robust to several model specifications, and isolated to drivers most affected by the opioid crisis: males and 25 to 34 year-olds.

Effects of resilience on impulsivity, cognition and depression during protracted withdrawal among Chinese male methamphetamine users

BACKGROUND

Methamphetamine (METH) dependence is a complex and dynamic public health problem. Long-term abuse of METH can increase numerous risks of mental and physical problems. Currently, the methods to reduce METH dependence and improve the withdrawal symptoms are limited and ineffective. Resilience is seen as a multidimensional and dynamic capability to recover or bounce back from stressful events and is also generally considered as a protective factor against mental dysfunction.

METHODS

One hundred thirty-four males with METH dependence were consecutively recruited from Huanglong Compulsory Isolated Detoxification Center between 2019 and 2021, of whom 112 were into the group. The Connor-Davidson Resilience Scale (CD-RISC), Self-rating depression scale (SDS), Self-rating anxiety scale (SAS), Barratt Impulsiveness Scale-11(BIS-11), and the Repeatable Battery for the Assessment of Neuropsychological Status (Rbans) were used to evaluate resilience, depression, anxiety, impulsivity, and cognition respectively.

RESULTS

The results mainly indicated that high resilience group showed lower SDS, SAS and BIS-11 scores than low resilience group (all p < 0.05). Besides, the total scores of Rbans were higher in high resilience groups than low resilience group (both p < 0.05). Moreover, linear regression results showed that resilience may be influenced by the scores of SDS and SAS.

CONCLUSIONS

Resilience is negatively correlated with impulsivity and depression. Besides, it is also positively associated with cognitive function. Drug users with higher resilience may have a strong ability to mobilize psychological resources to create a good psychological environment, which may have a positive effect on the relief or improvement of symptoms.

Neurophysiological Deficits During Reappraisal of Negative Emotional Stimuli in Opioid Misuse

BACKGROUND

Opioid misuse is hypothesized to compromise the ability to regulate negative emotions, as manifested through visceral and peripheral physiological signals. However, neurophysiological impairment of top-down cognitive emotion regulation in opioid misuse has not previously been shown.

METHODS

Patients with chronic pain who had been taking opioids for 90 days or longer (N = 149; female, n = 98) underwent a negative emotion regulation task with electroencephalography. Participants were instructed to view or reappraise negative images presented for 3 seconds. Using a validated cutoff score on the Current Opioid Misuse Measure, participants were classified as exhibiting aberrant drug-related behavior consistent with opioid misuse (MISUSE+) or as being low risk for opioid misuse (MISUSE-). Participants reported their craving in response to negative emotions over the past week.

RESULTS

We observed a group × condition interaction (p = .003) such that the MISUSE- group decreased the late positive potential of the electroencephalography during reappraisal, whereas the MISUSE+ group showed increased late positive potential during reappraisal. This deficit in negative emotion regulation remained significant after controlling for an array of potential confounding variables, including opioid dose, pain, and depression. Heightened late positive potential during reappraisal was associated with more severe opioid craving.

CONCLUSIONS

Opioid misuse may occasion top-down deficits in emotional regulation that begin as early as 400 ms after presentation of negative stimuli. It remains unknown whether emotion dysregulation is the cause, correlate, or consequence of opioid misuse. Nonetheless, targeting emotion dysregulation in opioid misuse with reappraisal-focused interventions may represent an important treatment approach.

Characteristics of depression, anxiety, impulsivity, and aggression among various types of drug users and factors for developing severe depression: a cross-sectional study

BACKGROUND

Mood disorder, impulsivity and aggression are common in drug users compared to healthy controls. However, no study has focused on the difference in various types of drug users. Therefore, the objective of this study was to explore the differences in depression, anxiety, impulsivity, and aggression among methamphetamine, heroin and polysubstance users and to further explore the risk factors for severe depression in the three groups.

METHODS

Drug users over 18 years old who met the DSM-V diagnostic criteria for substance -related disorders were included in the study. All participants completed a general questionnaire, the Zung Self-Rating Depression Scale (SDS), the Zung Self-Rating Anxiety Scale (SAS), Barratt impulsiveness Scale Version 11 (BIS-11), and the Buss-Perry Aggression Questionnaire (BPAQ). One-way ANOVAs or Chi-square tests were used to test the differences among the groups, correlation analysis was used to test the relationship between drug use and other parameters, and multiple logistic regression was conducted to assess the risk factors for severe depression.

RESULTS

A total of 1,486 participants were included, comprising 86.3% males with a mean age of 38.97 years. There was a significant difference in the percentage of severe depression and SDS scores among the three groups, but no significant difference was found in SAS, BIS-11 and BPAQ scores. Using methamphetamines, hostility and anxiety were risk factors for developing severe depression in all the participants and anxiety remained constant in the other three groups. Moreover, methamphetamine use was 2.16 and 3.35 times more likely to cause severe depression than heroin and polysubstance use, respectively. The initial age of substance use was negatively correlated with BPAQ, SAS, and SDS scores, whereas the drug use duration and addiction duration were positively correlated.

CONCLUSIONS

In this study, we found that the highest prevalence of severe depression was in participants using methamphetamines and that using methamphetamines, hostility, and anxiety were risk factors for developing severe depression. This result addressed an important gap in our knowledge of the different characteristics of depression, anxiety, impulsivity and aggression in various types of substance users and provides clinicians and policy-makers with directions for intervention and preventing relapse.

Deprivation Has Inconsistent Effects on Delay Discounting: A Review

Delay discounting, the tendency for outcomes to be devalued as they are more temporally remote, has implications as a target for behavioral interventions. Because of these implications, it is important to understand how different states individuals may face, such as deprivation, influence the degree of delay discounting. Both dual systems models and state-trait views of delay discounting assume that deprivation may result in steeper delay discounting. Despite early inconsistencies and mixed results, researchers have sometimes asserted that deprivation increases delay discounting, with few qualifications. The aim of this review was to determine what empirical effect, if any, deprivation has on delay discounting. We considered many kinds of deprivation, such as deprivation from sleep, drugs, and food in humans and non-human animals. For 23 studies, we analyzed the effect of deprivation on delay discounting by computing effect sizes for the difference between delay discounting in a control, or baseline, condition and delay discounting in a deprived state. We discuss these 23 studies and other relevant studies found in our search in a narrative review. Overall, we found mixed effects of deprivation on delay discounting. The effect may depend on what type of deprivation participants faced. Effect sizes for deprivation types ranged from small for sleep deprivation (Hedge's gs between −0.21 and 0.07) to large for opiate deprivation (Hedge's gs between 0.42 and 1.72). We discuss possible reasons why the effect of deprivation on delay discounting may depend on deprivation type, including the use of imagined manipulations and deprivation intensity. The inconsistency in results across studies, even when comparing within the same type of deprivation, indicates that more experiments are needed to reach a consensus on the effects of deprivation on delay discounting. A basic understanding of how states affect delay discounting may inform translational efforts.

Integrating Cognitive Dysfunction Accommodation Strategies Into Behavioral Interventions for Persons on Medication for Opioid Use Disorder

BACKGROUND

Cognitive dysfunction is disproportionately prevalent among persons with opioid use disorder (OUD). Specific domains of cognitive dysfunction (attention, executive functioning, memory, and information processing) may significantly impede treatment outcomes among patients on medication for OUD (MOUD). This limits patient's ability to learn, retain, and apply information conveyed in behavioral intervention sessions. Evidence-based accommodation strategies have been integrated into behavioral interventions for other patient populations with similar cognitive profiles as persons with OUD; however, the feasibility and efficacy of these strategies have not yet been tested among patients on MOUD in a drug treatment setting.

METHODS

We conducted a series of focus groups with 25 key informants (10 drug treatment providers and 15 patients on MOUD) in a drug treatment program in New Haven, CT. Using an inductive approach, we examined how cognitive dysfunction impedes participant's ability to retain, recall, and utilize HIV prevention information in the context of drug treatment.

RESULTS

Two main themes capture the overall responses of the key informants: (1) cognitive dysfunction issues and (2) accommodation strategy suggestions. Subthemes of accommodation strategies involved suggestions about particular evidence-based strategies that should be integrated into behavioral interventions for persons on MOUD. Specific accommodation strategies included: use of a written agenda, mindfulness meditation, multi-modal presentation of information, hands-on demonstrations, and a formal closure/summary of sessions.

CONCLUSIONS

Accommodation strategies to compensate for cognitive dysfunction were endorsed by both treatment providers and patients on MOUD. These accommodation strategies have the potential to enhance the efficacy of behavioral interventions to reduce HIV transmission among persons on MOUD as well as addiction severity, and overdose.

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.

Risk for opioid misuse in chronic pain patients is associated with endogenous opioid system dysregulation

µ-Opioid receptors (MOR) are a major target of endogenous and exogenous opioids, including opioid pain medications. The µ-opioid neurotransmitter system is heavily implicated in the pathophysiology of chronic pain and opioid use disorder and, as such, central measures of µ-opioid system functioning are increasingly being considered as putative biomarkers for risk to misuse opioids. To explore the relationship between MOR system function and risk for opioid misuse, 28 subjects with chronic nonspecific back pain completed a clinically validated measure of opioid misuse risk, the Pain Medication Questionnaire (PMQ), and were subsequently separated into high (PMQ > 21) and low (PMQ ≤ 21) opioid misuse risk groups. Chronic pain patients along with 15 control participants underwent two separate [¹¹C]-carfentanil positron emission tomography scans to explore MOR functional measures: one at baseline and one during a sustained pain-stress challenge, with the difference between the two providing an indirect measure of stress-induced endogenous opioid release. We found that chronic pain participants at high risk for opioid misuse displayed higher baseline MOR availability within the right amygdala relative to those at low risk. By contrast, patients at low risk for opioid misuse showed less pain-induced activation of MOR-mediated, endogenous opioid neurotransmission in the nucleus accumbens. This study links human in vivo MOR system functional measures to the development of addictive disorders and provides novel evidence that MORs and µ-opioid system responsivity may underlie risk to misuse opioids among chronic pain patients.

Mitragynine improves cognitive performance in morphine-withdrawn rats

RATIONALE

The treatment of opiate addiction is an unmet medical need. Repeated exposure to opiates disrupts cognitive performance. Opioid substitution therapy, with, e.g., methadone, may further exacerbate the cognitive deficits. Growing evidence suggests that mitragynine, the primary alkaloid from the Kratom (Mitragyna speciosa) leaves, may serve as a promising alternative therapy for opiate addiction. However, the knowledge of its health consequences is still limited.

OBJECTIVES

We aimed to examine the cognitive effects of mitragynine substitution in morphine-withdrawn rats. Furthermore, we asked whether neuronal addiction markers like the brain-derived neurotrophic factor (BDNF) and Ca²⁺/calmodulin-dependent kinase II alpha (αCaMKII) might mediate the observed effects.

METHODS

Male Sprague-Dawley rats were given morphine at escalating doses before treatment was discontinued to induce a spontaneous morphine withdrawal. Then, vehicle or mitragynine (5 mg/kg, 15 mg/kg, or 30 mg/kg) substitution was given for 3 days. A vehicle-treated group was used as a control. Withdrawal signs were scored after 24 h, 48 h, and 72 h, while novel object recognition (NOR) and attentional set-shifting (ASST) were tested during the substitution period.

RESULTS

Discontinuation of morphine significantly induced morphine withdrawal signs and cognitive deficit in the ASST. The substitution with mitragynine was able to alleviate the withdrawal signs. Mitragynine did not affect the recognition memory in the NOR but significantly improved the reversal learning deficit in the morphine-withdrawn rats.

CONCLUSIONS

These data support the idea that mitragynine could be used as safe medication therapy to treat opiate addiction with beneficial effects on cognitive deficits.

Clinical and Cognitive Effects of Computer Assisted Cognitive Remediation Method in Turkish Men with Opioid Use Disorder: A Randomized Controlled Trial

Objective: Substance use disorders are associated with significant cognitive impairments causing many individual or social problems besides poor treatment outcomes. The cognitive remediation method is effective in so many neuropsychiatric disorders. This study aimed to evaluate the effects of this method among individuals with opioid use disorder. Method:60 patients diagnosed with opioid use disorder under buprenorphine-naloxone treatment and who accepted the informed consent were included. Seven patients left the study initially. 53 male patients were randomly assigned to receive treatment in the usual control or cognitive remediation-intervention group. The intervention group completed 3 to 4 sessions a week, 8 different exercises in each session, for 4 weeks, a total of 12 sessions, individually. Addiction Profile Indeks, Barrat Impulsivity Scale-SF, CGI, and Delay Discounting scores were measured before and after the 1 month cognitive Remediation practices. Three months later, patients were contacted, and their remission status was evaluated. Results: In the intervention group; 17(89.5%) people had remission and 2(10.5%) people had relapse. In the control group, 7(31.8%) individuals had remission, and 15(68.2%) had relapsed at the end of the 3 months. It was determined that craving, addiction severity, and self-reported and behavioral impulsivity values decreased while the improvement in treatment response was higher in the intervention group. Conclusion: Our results showed that the computer-assisted cognitive remediation method, in addition to buprenorphine-naloxone treatment, improves treatment response, increases remission, and has positive clinical and cognitive effects on individuals with opioid use disorder. It suggests that cognitive remediation practices can be added to the treatment programs for addiction.

Chronic heroin use disorder and the brain: Current evidence and future implications

The incidence of chronic heroin use disorder, including overdose deaths, has reached epidemic proportions. Here we summarise and evaluate our knowledge of the relationship between chronic heroin use disorder and the brain through a narrative review. A broad range of areas was considered including causal mechanisms, cognitive and neurological consequences of chronic heroin use and novel neuroscience-based clinical interventions. Chronic heroin use is associated with limited or very limited evidence of impairments in memory, cognitive impulsivity, non-planning impulsivity, compulsivity and decision-making. Additionally, there is some evidence for certain neurological disorders being caused by chronic heroin use, including toxic leukoencephalopathy and neurodegeneration. However, there is insufficient evidence on whether these impairments and disorders recover after abstinence. Whilst there is a high prevalence of comorbid psychiatric disorders, there is no clear evidence that chronic heroin use per se causes depression, bipolar disorder, PTSD and/or psychosis. Despite the growing burden on society from heroin use, knowledge of the long-term effects of chronic heroin use disorder on the brain remains limited. Nevertheless, there is evidence for progress in neuroscience-based interventions being made in two areas: assessment (cognitive assessment and neuroimaging) and interventions (cognitive training/remediation and neuromodulation). Longitudinal studies are needed to unravel addiction and neurotoxic mechanisms and clarify the role of pre-existing psychiatric symptoms and cognitive impairments.

Preconception paternal morphine exposure leads to an impulsive phenotype in male rat progeny

RATIONALE

Identifying the long-term neurocognitive implications of opioid addiction may further our understanding of the compulsive nature of this brain disorder. The aim of this study was to examine the effects of paternal adolescent opiate exposure on cognitive performance (visual attention, impulsivity, and compulsivity) in the next generation.

METHODS

Male Wistar rats received escalating doses of morphine (2.5-25 mg/kg, s.c.) or saline for 10 days during adolescence (P30-39). In adulthood (P70-80), these rats were allowed to mate with drug-naive females. Male offspring from morphine- and saline-exposed sires, once in adulthood, were trained and tested in the 5-choice serial reaction time test (5-CSRTT) to evaluate their cognitive abilities under baseline, drug-free conditions as well as following acute (1, 3, 5 mg/kg morphine) and subchronic morphine (5 mg/kg morphine for 5 days) treatment. Behavioral effects of the opioid receptor antagonist naloxone were also assessed.

RESULTS

Morphine-sired offspring exhibited delayed learning when the shortest stimulus duration (1 s) was introduced, i.e., when cognitive load was highest. These subjects also exhibited a reduced ability to exert inhibitory control, as reflected by increased premature and perseverative responding under drug-free baseline conditions in comparison to saline-sired rats. These impairments could not be reversed by administration of naloxone. Moreover, impulsive behavior was further enhanced in morphine-sired rats following acute and subchronic morphine treatment.

CONCLUSION

Paternal opiate exposure during adolescence was found to primarily impair inhibitory control in male progeny. These results further our understanding of the long-term costs and risk of opioid abuse, extending across generations.

Improved Executive Functions and Reduced Craving in Youths with Methamphetamine Addiction: Evidence from Combined Transcranial Direct Current Stimulation with Mindfulness Treatment

OBJECTIVE

Transcranial direct current stimulation (tDCS) and mindfulness practices have been proposed as a potential approach to improve executive functions (EFs) and reduce craving in persons with substance use disorders. Based on the neural mechanisms of action of each of these interventions, the combination of both non-pharmacological interventions might have additive effects. In the current study, the effects of tDCS combined with mindfulness-based substance abuse treatment (MBSAT) to improve EFs and reduce craving were investigated in early abstinent methamphetamine abuse.

METHODS

Eighty (youths aged between 18 and 21) early-abstinent methamphetamine users were randomly assigned to the research groups (tDCS group [n = 20], mindfulness group [n = 20], combined mindfulness-tDCS group [n = 20], and sham group [n = 20]). Active tDCS (1.5 mA,20 min, 12 sessions) or sham tDCS was appliedover the left dorsolateral prefrontal cortex and the MBSAT protocol was used over twelve 50-min sessions.

RESULTS

Both in the post-test phase (immediately after the intervention) and follow-up phase (one month after the intervention), performance in most EFs tasks significantly improved in the combination group which received real tDCS ＋ MBSAT, as compared to baseline values and sham stimulation group. Similarly, a significant reduction in craving was observed after intervention inall treatment groups, but not the sham stimulation group. Interestingly, the increase in EFs and the reduction in craving post versus pre tDCS ＋ MBSAT intervention were correlated.

CONCLUSION

Findings from the current study provide initial support for the clinical effectiveness of combination tDCS ＋ MBSAT, possibly influencing cognitive/affective processes.

Prefrontal fNIRS-based clinical data analysis of brain functions in individuals abusing different types of drugs

Background

The activation degree of the orbitofrontal cortex (OFC) functional area in drug abusers is directly related to the craving for drugs and the tolerance to punishment. Currently, among the clinical research on drug rehabilitation, there has been little analysis of the OFC activation in individuals abusing different types of drugs, including heroin, methamphetamine, and mixed drugs. Therefore, it becomes urgently necessary to clinically investigate the abuse of different drugs, so as to explore the effects of different types of drugs on the human brain.

Methods

Based on prefrontal high-density functional near-infrared spectroscopy (fNIRS), this research designs an experiment that includes resting and drug addiction induction. Hemoglobin concentrations of 30 drug users (10 on methamphetamine, 10 on heroin, and 10 on mixed drugs) were collected using fNIRS and analyzed by combining algorithm and statistics.

Results

Linear discriminant analysis (LDA), Support vector machine (SVM) and Machine-learning algorithm was implemented to classify different drug abusers. Oxygenated hemoglobin (HbO2) activations in the OFC of different drug abusers were statistically analyzed, and the differences were confirmed. Innovative findings: in both the Right-OFC and Left-OFC areas, methamphetamine abusers had the highest degree of OFC activation, followed by those abusing mixed drugs, and heroin abusers had the lowest. The same result was obtained when OFC activation was investigated without distinguishing the left and right hemispheres.

Conclusions

The findings confirmed the significant differences among different drug abusers and the patterns of OFC activations, providing a theoretical basis for personalized clinical treatment of drug rehabilitation in the future.

The effect of bilateral tDCS over dorsolateral prefrontal cortex on the cognitive abilities of men with opioid use disorder under methadone therapy: A sham-controlled clinical trial

Background/aim

Opioid use disorder (OUD) can have negative impact on cognitive functions. This study aims to evaluate the effect of bilateral transcranial direct-current stimulation (tDCS) over the right/left dorsolateral prefrontal cortex (DLPFC) on the cognitive abilities of OUD men.

Methods

This study is a double-blind sham-controlled randomized clinical trial with a pretest/posttest design. Participants were 31 men with OUD living in Zanjan, Iran, assigned to three groups of left anode/right cathode tDCS, right anode/left cathode tDCS, and sham tDCS. The two active groups received tDCS (2 mA) at 10 sessions each for 10–20 min. The Cognitive Abilities Questionnaire (CAQ) in Persian was used to measure their cognitive abilities before and after intervention. Collected data were analyzed in SPSS v.22 software.

Results

Bilateral DLPFC stimulation resulted in a significant improvement in cognitive flexibility, planning, decision making, inhibitory control/selective attention, and memory of patients in the two active tDCS groups, while the sham tDCS had no significant effect on their cognitive abilities.

Conclusion

Bilateral tDCS over DLPFC, as an effective and complementary treatment, can improve the cognitive abilities of men with OUD.

Trial registration: This study is a double-blind sham-controlled clinical trial (Parallel, IRCT20170513033946N5. Registered 19 Jan 2019, https://en.irct.ir/trial/36081).

Neurocognitive, psychiatric, and substance use characteristics in a diverse sample of persons with OUD who are starting methadone or buprenorphine/naloxone in opioid treatment programs

BACKGROUND

Medications for opioid use disorder such as opioid agonist treatment (OAT, including methadone, buprenorphine) are the gold standard intervention for opioid use disorder (OUD). Persons with OUD have high rates of neurocognitive impairment and psychiatric and substance use disorders, but few studies have examined these characteristics in diverse patients initiating OAT in opioid treatment programs (OTPs). Additionally, in these individuals, poor neurocognitive functioning and psychiatric/other substance use disorders are associated with poor OUD treatment outcomes. Given rapid changes in the opioid epidemic, we sought to replicate findings from our pilot study by examining these characteristics in a large diverse sample of persons with OUD starting OTP-based OAT.

METHODS

Ninety-seven adults with OUD (M age = 42.2 years [SD = 10.3]; M education = 11.4 years [SD = 2.3]; 27% female; 22% non-Hispanic white) were enrolled in a randomized longitudinal trial evaluating methadone versus buprenorphine/naloxone on neurocognitive functioning. All participants completed a comprehensive neurocognitive, psychiatric, and substance use evaluation within one week of initiating OAT.

RESULTS

Most of the sample met criteria for learning (79%) or memory (69%) impairment. Half exhibited symptoms of current depression, and comorbid substance use was highly prevalent. Lifetime cannabis and cocaine use disorders were associated with better neurocognitive functioning, while depression was associated with worse neurocognitive functioning.

CONCLUSIONS

Learning and memory impairment are highly prevalent in persons with OUD starting treatment with either methadone or buprenorphine/naloxone in OTPs. Depression and comorbid substance use are prevalent among these individuals, but neither impact learning or memory. However, depression is associated with neurocognitive impairment in other domains. These findings might allow clinicians to help persons with OUD starting OAT to develop compensatory strategies for learning and memory, while providing adjunctive treatment for depression. Trial Registration NCT, NCT01733693. Registered November 4, 2012, https://clinicaltrials.gov/ct2/show/NCT01733693 .

Effects of chronic tramadol administration on cognitive flexibility in mice

RATIONALE

Tramadol is widely used for pain relief especially in seniors. However, long-term use of tramadol has serious adverse effects, including cognitive impairment. Besides its memory effects, already demonstrated in animals, a recent clinical report suggests that tramadol could also affect executive function in seniors. Several studies have hypothesized that the anti-muscarinic properties of tramadol could be responsible for the deleterious effects of tramadol on cognition.

OBJECTIVES

We aimed at investigating the effects of chronic administration of tramadol on cognitive flexibility in adult male mice, as assessed by a visual discrimination reversal task using a touchscreen device. The effects of tramadol were further compared to those of scopolamine, a reference muscarinic antagonist.

RESULTS

We found that, during the early phase of the reversal task, when cognitive flexibility is most in demand, both tramadol-treated mice (20 mg/kg, s.c., twice a day) and scopolamine-treated mice (0.5 mg/kg, s.c., twice a day) needed more correction trials and showed a higher perseveration index than saline-treated mice. Therefore, tramadol affects cognitive flexibility, and its anticholinergic properties could be at least partly involved in these deficits.

CONCLUSIONS

In view of these deleterious cognitive effects of tramadol, physicians should be cautious when prescribing this analgesic, especially in seniors who are more vulnerable to adverse drug events and in which alternative prescription should be preferred whenever possible.

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.