Prevalence and predictors of peripheral neuropathy after chemotherapy: Outcomes from the Detroit Research on Cancer Survivorship (ROCS) cohort

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Background: Increased life expectancy for cancer survivors following advances in treatment has led to a greater likelihood of developing long-term complications. Among them is chemotherapy-induced peripheral neuropathy (CIPN), which adversely impacts the functional capacity of survivors. We assessed prevalence and predictors of CIPN in a cohort of African-American (AA) cancer survivors. Methods: The study population included 633 breast, colorectal, prostate and lung cancer survivors who received chemotherapy and participated in the Detroit Research on Cancer Survivorship (ROCS) study. Presence of CIPN was based on self-reported pain, numbness or tingling in the hands or feet, occurring either for the first time or worsening after chemotherapy. If participants reported continued CIPN at the time of survey, their symptoms were reported as persistent. CIPN severity was self-reported as mild, moderate or severe. Logistic regression analysis was used to evaluate socio-demographic and clinical factors (including 12 common comorbid conditions) associated with CIPN prevalence, persistence and severity. Results: Overall, 67% of the cohort reported CIPN at a mean time of 25.3 months (range 2-74 months) after cancer diagnosis, and 51% reported persistent CIPN. The distribution of CIPN severity consisted of 32.2% with mild, 30.8% with moderate, and 36.9% with moderate to severe symptoms. Diagnosis of primary breast (OR 3.99, 95% CI 1.52-10.46) or colorectal cancers (OR 5.24, 95% CI 2.17-12.69) conferred greater CIPN prevalence relative to a diagnosis of prostate cancer. The presence of each additional comorbid condition among those outlined in the survey also conferred a 20% greater prevalence of CIPN (OR 1.2, 95% CI 1.03-1.39). Similar trends were seen among those who reported persistent CIPN. Using age > 65 at diagnosis as the reference group, age < 50 (OR 2.64, 95% CI 1.43-4.88) and age 51-64 (OR 1.96, 95% CI 1.14-3.35) resulted in an increased risk of moderate or severe compared to mild CIPN. Conclusions: In the Detroit ROCS cohort, CIPN was reported in two-thirds of cancer survivors receiving chemotherapy. Out of them, more than one-third reported moderate to severe symptoms, more commonly seen among those age < 65. Consideration of CIPN as a prominent long-term complication of cancer treatment should play a role in treatment decisions and development of new chemotherapy regimens.

β-Arrestin 2 (ARRB2) Polymorphism is Associated With Adverse Consequences of Chronic Heroin Use

BACKGROUND AND OBJECTIVES

β-arrestin 2 is an intracellular protein recruited during the activation of G-protein-coupled receptors. In preclinical studies, β-arrestin 2 has been implicated in µ-opioid receptor desensitization and internalization and the development of opioid tolerance and dependence. The present study investigated relationships between variants in the gene encoding β-arrestin 2 (ARRB2) and clinically relevant phenotypes among individuals with opioid use disorder (OUD). We hypothesized that ARRB2 variants would be associated with the negative effects of long-term heroin use.

METHODS

Chronic heroin users (N = 201; n = 103 African American; n = 98 Caucasian) were genotyped for ARRB2 r1045280 (synonymous, also affecting binding motif of transcription factor GTF2IRD1), rs2036657 (3'UTR) and rs3786047 (intron) and assessed for the past-month frequency of use, injection use, and lifetime duration of heroin use, number of heroin quit-attempts, and heroin use-related consequences.

RESULTS

Lifetime heroin-use consequences (especially occupational and health-related) were significantly lower for African American ARRB2 r1045280 C-allele carriers compared with the TT genotype. There was no significant genotype difference in the Caucasian group. ARRB2 rs2036657 was in strong linkage disequilibrium with rs1045280.

DISCUSSION AND CONCLUSIONS

These results, consistent with extant data, illustrate a role for ancestry-dependent allelic variation in ARRB2 r1045280 on heroin-use consequences. The ARRB2 r1045280 C-allele played a protective role in African-descent participants.

SCIENTIFIC SIGNIFICANCE

These first-in-human findings, which should be replicated, provide support for mechanistic investigations of ARRB2 and related intracellular signaling molecules in OUD etiology, treatment, and relapse prevention. (Am J Addict 2021;00:00-00).

N-acetylcysteine reduces cocaine-seeking behavior and anterior cingulate glutamate/glutamine levels among cocaine-dependent individuals

N-acetylcysteine (NAC) is a cystine prodrug shown to reduce cocaine- and cue-primed reinstatement of cocaine-seeking behavior in preclinical studies. In this inpatient study, the effects of NAC maintenance versus placebo on cocaine-seeking behavior were examined during cocaine-primed and unprimed self-administration sessions among non-treatment-seeking, cocaine-dependent individuals. Twelve participants completed this double-blind, placebo-controlled, within-subject crossover study. Each participant was maintained for 1 week (Sat-Fri) on NAC (1200-mg TID; 3600 mg/day total) and 1 week on placebo (0-mg TID); medication order was randomized. A subset of participants underwent proton magnetic resonance spectroscopy scans (n = 8) on the third day of medication (Mon) to assess neurochemistry in the rostral anterior cingulate (rACC; voxel = 4.5 cm³ ). In four randomized sessions (Tue-Fri) each week, each participant could earn unit amounts of cocaine (10 mg, fixed) versus money ($0.50 vs. $1.50) on a choice, progressive ratio schedule after insufflating active versus placebo cocaine-priming doses (110 mg vs. 4 mg). Relative to the placebo priming dose, the active cocaine priming dose (110 mg) increased cocaine-seeking behavior (p = .003). NAC reduced cocaine-primed cocaine-seeking behavior compared with placebo levels (p = .044) but did not alter placebo-primed cocaine-seeking behavior. The larger money alternative ($1.50) suppressed cocaine-seeking behavior relative to the smaller money alternative ($0.50; p = .011). Compared with placebo levels, NAC significantly decreased rACC glutamate + glutamine levels (p = .035) and numerically decreased rACC glutamate levels (p = .085). These preliminary findings indicate that NAC suppresses cocaine-seeking behavior in some, but not all, experimental scenarios. Further, our findings suggest NAC may exert its therapeutic effects by modulating excitatory tone in the rACC.

Demand curve analysis of marijuana use among persons living with HIV

BACKGROUND

Despite medicalization and legalization of marijuana use, factors influencing demand for marijuana among persons living with HIV (PLWH) are incompletely understood. This knowledge gap undermines effective clinical management and policies. This study used demand curve simulation methods to address these issues.

METHODS

Marijuana-using PLWH (N = 119) completed experimental tasks to simulate amount of marijuana purchasing/use across different costs (money or time), and likelihood of reselling marijuana or marijuana therapeutic-use registration card in relation to profits. Additional simulations assessed purchasing of marijuana relative to other drug and non-drug goods.

RESULTS

Simulated marijuana use decreased as money and time costs increased. Consumption was greater for participants with more severe Cannabis Use Disorder (CUD) and anxiety, intermediate pain levels, and past 90-day opioid use. Whereas few participants chose to sell their registration card, marijuana resale (diversion) steeply increased with profit. Likelihood of seeking marijuana therapeutic-use certification decreased in relation to registration card money cost, having to visit more physicians to get a signature, and delay to receiving the card, and increased with duration of certification. Participants who reported recent opioid use were more likely to seek certification. Consumption of several commodities assessed was independent of marijuana.

CONCLUSIONS

Simulated marijuana use was related to participants' clinical profile (CUD, anxiety and pain symptoms, recent opioid use), and unrelated to purchasing other goods. Likelihood of seeking marijuana therapeutic-use registration was affected by several types of costs and recent opioid use. Participants were unlikely to divert registration cards. We discuss clinical and policy implications of these findings.

US national treatment admissions with opioids and benzodiazepines

INTRODUCTION AND AIMS

Opioids and benzodiazepines (O/BZD) are increasingly involved in drug overdose deaths in the USA. Expanding treatment capacity may reduce these deaths. Knowledge about co-occurring O/BZD admissions compared to opioid admissions (opioid) is needed to plan this expansion.

DESIGN AND METHODS

US treatment admissions to specialty facilities for 2011-2017 were analysed for trends and 2017 for group differences. Due to 1.9 million admissions in 2017, comparisons between O/BZD and opioid admissions were summarised as effect sizes. Additional analysis compared the administratively pre-coded category 'other opiates and synthetics' to other opiates and synthetics/benzodiazepines admissions to control for possible similarity in drug source. Differences within O/BZD admissions by primary drug were explored.

RESULTS

Although opioid admissions showed a steady increase over time (25.9% to 38.2%), O/BZD admissions showed increases until decline in 2017 (3.2% to 4.0%). In 2017 no factor reached moderate effect size (≥0.2) in group comparisons or within the O/BZD admissions. Heroin was self-reported in 70% of both O/BZD and opioid admissions.

DISCUSSION AND CONCLUSIONS

No meaningful US national differences on data routinely collected were found for O/BZD compared to opioid admissions including the subgroup with other opiates and synthetics only. Efforts to expand existing opioid treatment in specialty treatments may help reduce opioid and O/BZD deaths. However, the analysis could not address whether changes in treatment would improve outcomes.

A neurobiological correlate of stress-induced nicotine-seeking behavior among cigarette smokers

Stress is known to influence smoking relapse. Experimental studies indicate that acute stress increases nicotine-seeking behavior, yet neurobiological mechanisms remain poorly understood. Herein, we investigated disrupted excitatory neural activity in the dorsolateral prefrontal cortex (dlPFC) as a mechanism of stress-induced nicotine-seeking behavior. Non-treatment-seeking cigarette smokers were screened for psychiatric, medical, and neuroimaging contraindications. Using a double-blind, placebo-controlled, randomized crossover design, participants (N = 21) completed two oral-dosing sessions: stress (yohimbine 54 mg + hydrocortisone 10 mg) vs placebo (lactose 54 mg + lactose 10 mg). During each experimental session, working memory proficiency, dlPFC excitatory neural activity, nicotine-seeking behavior, and subjective effects were measured. dlPFC excitatory neural activity was quantified via glutamate modulation during working memory performance using functional proton magnetic resonance spectroscopy. Nicotine-seeking behavior was assayed using a cigarette puffs vs money choice progressive ratio task. Results indicated that yohimbine + hydrocortisone evoked a sustained physiological stress response (elevated heart rate, blood pressure, saliva cortisol, and saliva α-amylase levels; ps < .05). Relative to placebo levels, acute stress increased nicotine-seeking behavior (ps < .05), disrupted dlPFC glutamate modulation (p = .025), and impaired dlPFC function (working memory proficiency; ps < .05). The stress-induced increase in nicotine-seeking behavior was linearly related to the stress-induced disruption of dlPFC glutamate modulation (R²  = 0.24-0.37; ps < .05). These findings suggest that disrupted dlPFC excitatory neural activity is a neurobiological correlate of acute stress-induced nicotine-seeking behavior. These findings further emphasize the central role of the dlPFC in regulating drug-seeking behavior. Future studies are needed to evaluate interventions to improve dlPFC resilience to acute stress effects, including neurostimulation, working memory training, and "anti-stress" medications.

Peripheral neuropathy after breast cancer: An analysis of data from the Women’s Health Initiative Life and Longevity After Cancer cohort

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Background: There are over 3.8 million breast cancer survivors in the United States, and many experience long-term side effects from chemotherapy. Factors associated with peripheral neuropathy (PN), one troubling side effect, following breast cancer among women are unknown. Methods: We included 2,420 women enrolled in the Women’s Health Initiative and diagnosed prospectively with local or regional stage breast cancer and followed in the Life and Longevity After Cancer (LILAC) study. PN was assessed by response to the baseline LILAC questionnaire regarding the presence of “nerve problems, tingling sensations” after treatment. Data were collected on initial course of therapy (surgery, radiation, and chemotherapy) through Medicare linkage or the LILAC staging and treatment form. Chi-square and Wilcoxon rank-sum tests were used for univariate comparison of socio-demographics, clinical and diagnosis characteristics associated with the presence or absence of PN. Results: The sample included 1,913 women (79%) with local and 507 women (21%) with regional stage disease. Initial course of therapy included either surgery alone (21%), surgery and radiation (53%), or surgery and chemotherapy (+/- radiation) (26%). Seventeen percent of women reported experiencing PN days (30%), months (46%) or years (24%) following treatment. Three-quarters (74%) reported ongoing symptoms at the time of the LILAC survey. PN was reported by 33% of chemotherapy recipients, compared to 12% in the surgery alone group, and 11% in the group that received surgery and radiation (p<0.0001). The prevalence of PN was higher among women receiving regimens containing paclitaxel (52%) and docetaxel (39%), compared to those receiving other chemotherapy (17%) (p<0.0001). Conclusions: PN is an important complication of taxane-based chemotherapy. Further analysis will explore the relationship between socio-demographic, clinical and treatment on the development, timing of, and severity of PN after cancer directed therapy.

Heroin delay discounting and impulsivity: Modulation by DRD1 genetic variation

BACKGROUND

Dopamine D1 receptors (encoded by DRD1) are implicated in drug addiction and high-risk behaviors. Delay discounting (DD) procedures measure decisional balance between choosing smaller/sooner rewards vs larger/later rewards. Individuals with higher DD (rapid discounting) are prone to maladaptive behaviors that provide immediate reinforcement (eg, substance use). DRD1 variants have been linked with increased DD (in healthy volunteers) and opioid abuse. This study determined whether four dopaminergic functional variants modulated heroin DD and impulsivity.

METHODS

Substance use, DD, and genotype data (DRD1 rs686 and rs5326, DRD3 rs6280, COMT rs4680) were obtained from 106 current heroin users. Subjects completed an array of DD choices during two imagined conditions: heroin satiation and withdrawal. Rewards were expressed as $10 heroin bag units, with maximum delayed amount of 30 bags. Delays progressively increased from 3 to 96 hours.

RESULTS

DRD1 rs686 (A/A, n = 25; G/A, n = 56; G/G, n = 25) was linearly related to the difference in heroin DD (area under the curve; AUC) between the heroin satiation and withdrawal conditions; specifically, G/G homozygotes had a significantly smaller (satiation minus withdrawal) AUC difference score had higher drug-use impulsivity questionnaire scores, relative to A/A homozygotes, with G/A intermediate. DRD3 and COMT variants were not associated with these DD and impulsivity outcomes.

CONCLUSION

DRD1 rs686 modulated the difference in heroin DD score between pharmacological states and was associated with drug-use impulsivity. These data support a role of DRD1 in opioid DD and impulsive behaviors.

History of regular nonmedical sedative and/or alcohol use differentiates substance-use patterns and consequences among chronic heroin users

BACKGROUND

Concurrent use of sedating substances (e.g. alcohol or benzodiazepines) with opioids is associated with increased negative consequences of opioid use; however, few studies have attempted to differentiate effects of using sedating substances on heroin-use outcomes. This study examines differences between heroin users who use alcohol or misuse sedatives regularly and those who do not.

METHODS

Substance-use data were collected from 367 non-treatment seeking, chronic heroin-using, 18-to-55 year-old participants. We created 4 groups based on self-reported lifetime history of regular (at least weekly) substance use: heroin only (n = 95), heroin and sedatives (n = 21), heroin and alcohol (n = 151), and heroin, sedative, and alcohol (n = 100). Chi-square analyses and ANOVAs with Bonferroni post hoc tests were used to explore differences between these groups.

RESULTS

Heroin users who denied lifetime alcohol or nonmedical sedative use regularly endorsed fewer consequences associated with any substance they had used. Total adverse consequences of heroin use (e.g. health problems) were significantly higher among those who misused sedatives regularly, irrespective of alcohol use history (F(3,361) = 10.21; p < .001). Regular alcohol use did not independently impact heroin consequences but was associated with increased use of other substances.

CONCLUSIONS

Although polysubstance use is normative among heroin users, the risks depend on the substances used. Regular sedative use is associated with increased heroin consequences whereas regular alcohol use is not. This study refines the investigation of polysubstance use and highlights subgroup differences depending on types of substances used regularly. This knowledge is critical for understanding substance-use motivations and creating avenues for harm reduction.

A Comparison of Substance Use Patterns Among Lifetime Heroin-Injecting Individuals By Racial Groups

BACKGROUND

Studies have identified differential substance use patterns by racial groups. One of the most commonly reported differences is a higher rate of injection drug use (IDU) among Non-Hispanic Whites compared to African Americans, but this is complicated by factors related to IDU (e.g., earlier drug-use initiation) that overlap with being White.

OBJECTIVE

We explored differential substance use-patterns by racial groups within a sample of injection heroin users.

METHODS

Substance-use data were collected from 373 not-in-treatment heroin users who endorsed any lifetime injection use (69.4% male). We examined differences in substance-use patterns (e.g., age of initiation, gateway adherence) by racial groups. Multiple t-tests with Bonferroni correction were conducted to understand which demographic and substance-use characteristics varied by racial groups.

RESULTS

Relative to Non-Hispanic Whites, African Americans (45.8% of sample) were more likely to start using heroin earlier in their life, but also more likely to experience a longer delay between starting and regularly using heroin. We also identified differences in the degree of (injection) heroin-use consequences by racial groups. After correcting for multiple comparisons and controlling for age and gender, we observed differences for six substance-use and demographic characteristics by racial group. White participants were younger, started cocaine use earlier, and experienced more heroin-use consequences across two separate domains.

CONCLUSIONS

After controlling for injection use, we observed differential substance-use characteristics by racial groups. The findings could be used to develop targeted prevention and harm-reduction strategies.

Gender-specific predictors of methadone treatment outcomes among African Americans at an urban clinic

Background: African American patients with opioid use disorder (OUD) have demonstrated poorer methadone maintenance treatment (MMT) outcomes compared with white patients. This issue is further complicated in urban settings, where African Americans experience high rates of poverty and publicly funded treatment. Despite interrelated factors that disadvantage African Americans, the literature focusing on this population is scant. To address this shortcoming, we conducted the first investigation of gender differences and gender-specific MMT outcome predictors among African Americans (or any racial minority population). This study provides gender-specific findings to improve African American MMT outcomes. Methods: We studied 211 African American patients (male: n = 137, 64.9%) at an urban, university-affiliated MMT clinic. We used existing intake data to assess baseline demographic, substance use, mental health, and interpersonal factors. Primary outcomes were 3-month drug⁺ (positive) urine drug screen (UDS) results and treatment retention. Results: Women were more likely (than men) to endorse histories of interpersonal violence, substance abuse in their social network, and mental health problems. Men reported a greater likelihood (than women) for early opioid-use onset and a lack of prior MMT. There were no gender differences in 3-month drug⁺ UDS or treatment retention. In multivariable analyses among women, no baseline factors predicted 3-month opioid⁺ UDS and physical abuse history predicted a higher proportion of 3-month cocaine⁺ UDS. Among men, primary injection opioid use and older age best predicted a higher proportion of 3-month cocaine⁺ UDS and parent substance abuse predicted shorter retention. In both gender-stratified analyses, higher proportions of 3-month opioid⁺ UDS and cocaine⁺ UDS predicted shorter retention. Conclusions: This study offers an analysis of gender differences in risk factors, MMT outcomes, and gender-specific predictors among African American patients. MMT clinics should tailor assessment and treatment protocols to address gender-specific needs.

Injection opioid use as a predictor of treatment outcomes among methadone-maintained opioid-dependent patients

BACKGROUND

Injection opioid use is associated with more severe health and psychosocial consequences relative to non-injection use, but few studies have examined whether injection use is associated with methadone maintenance treatment outcomes. The present study examined differential MMT outcomes among opioid injectors and non-injectors.

METHODS

Data were extracted from the clinic charts of opioid-dependent MMT patients (N = 290; n = 115 injectors) enrolled in a university-affiliated, urban MMT clinic. Injection status was examined as a predictor of short- (3-month opioid, cocaine, benzodiazepine and cannabis urine drug screens) and long- (days retained in treatment) term MMT outcomes.

RESULTS

Bivariate analyses revealed injection users were less likely to be African American and to have completed high school, were more likely to have started heroin use before age 21, to report having hepatitis C, to report a baseline cocaine use disorder, and had higher methadone doses at 3-months into treatment. Injection status significantly predicted a greater proportion of cocaine-positive urine drug screens in the first 3 months of treatment, but did not significantly predict opioid, benzodiazepine or cannabis drug screens, or length of treatment retention.

CONCLUSION

This is one of a handful of studies to examine injection status as a predictor of MMT outcomes. Injection status is associated with cocaine use early in treatment, which has implications for the focus of treatment.

Efficacy and safety of a monthly buprenorphine depot injection for opioid use disorder: a multicentre, randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

RBP-6000, referred to as BUP-XR (extended-release buprenorphine), is a subcutaneously injected, monthly buprenorphine treatment for opioid use disorder. BUP-XR provides sustained buprenorphine plasma concentrations to block drug-liking of abused opioids over the entire monthly dosing period, while controlling withdrawal and craving symptoms. Administration of BUP-XR in a health-care setting also mitigates abuse, misuse, diversion, and unintentional exposure. We aimed to investigate the efficacy of different BUP-XR dosing regimens in participants with opioid use disorder.

METHODS

This randomised, double-blind, placebo-controlled, phase 3 trial was done at 36 treatment centres in the USA. Treatment-seeking adults aged 18-65 years who had moderate or severe opioid use disorder (as defined by the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders) entered an open-label run-in phase of up to 2 weeks' treatment with buprenorphine-naloxone sublingual film. Eligible participants were then randomly assigned (4:4:1:1) with an interactive voice/web-response system to receive BUP-XR 300 mg/300 mg (six injections of 300 mg), BUP-XR 300 mg/100 mg (two injections of 300 mg plus four injections of 100 mg), or volume-matched placebo every 28 days, and received weekly individual drug counselling. No supplemental buprenorphine was allowed. The primary efficacy endpoint was participants' percentage abstinence from opioid use, defined as the percentage of each participant's negative urine samples and self-reports of illicit opioid use from week 5 to week 24, analysed in the full analysis set. Safety was assessed in all participants who received at least one dose of BUP-XR or placebo. This study is registered with ClinicalTrials.gov, number NCT02357901.

FINDINGS

From Jan 28, 2015, to Nov 12, 2015, 1187 potential participants were screened, 665 entered run-in, and 504 received BUP-XR 300 mg/300 mg (n=201), BUP-XR 300 mg/100 mg (n=203), or placebo (n=100). Mean participants' percentage abstinence was 41·3% (SD 39·7) for BUP-XR 300 mg/300 mg and 42·7% (38·5) for 300 mg/100 mg, compared with 5·0% (17·0) for placebo (p<0·0001 for both BUP-XR regimens). No compensatory non-opioid drug use was observed during BUP-XR treatment. The most common adverse events were headache (17 [8%] participants in the BUP-XR 300 mg/300 mg group vs 19 [9%] participants in the BUP-XR 300 mg/100 mg group vs six [6%] participants in the placebo group), constipation (16 [8%] vs 19 [9%] vs 0), nausea (16 [8%] vs 18 [9%] vs five [5%]), and injection-site pruritis (19 [9%] vs 13 [6%] vs four [4%]). The BUP-XR safety profile was consistent with other buprenorphine products for treatment of opioid use disorder, except for injection-site reactions, which were reported in more than 5% of all participants who received BUP-XR, but were mostly mild and not treatment-limiting.

INTERPRETATION

Participants' percentage abstinence was significantly higher in both BUP-XR groups than in the placebo group. Treatment with BUP-XR was also well tolerated. The availability of this monthly formulation, delivered by health-care providers, represents an advance in treatment for opioid use disorder that enhances the benefits of buprenorphine by delivering sustained, optimal exposure, while reducing risks of current buprenorphine products.

FUNDING

Indivior.

Pharmacological stress impairs working memory performance and attenuates dorsolateral prefrontal cortex glutamate modulation

Working memory processes are associated with the dorsolateral prefrontal cortex (dlPFC). Prior research using proton functional magnetic resonance spectroscopy (¹H fMRS) observed significant dlPFC glutamate modulation during letter 2-back performance, indicative of working memory-driven increase in excitatory neural activity. Acute stress has been shown to impair working memory performance. Herein, we quantified dlPFC glutamate modulation during working memory under placebo (oral lactose) and acute stress conditions (oral yohimbine 54 mg + hydrocortisone 10 mg). Using a double-blind, randomized crossover design, participants (N = 19) completed a letter 2-back task during left dlPFC ¹H fMRS acquisition (Brodmann areas 45/46; 4.5 cm³). An automated fitting procedure integrated with LCModel was used to quantify glutamate levels. Working memory-induced glutamate modulation was calculated as percentage change in glutamate levels from passive visual fixation to 2-back levels. Results indicated acute stress significantly attenuated working memory-induced glutamate modulation and impaired 2-back response accuracy, relative to placebo levels. Follow-up analyses indicated 2-back performance significantly modulated glutamate levels relative to passive visual fixation during placebo but not acute stress. Biomarkers, including blood pressure and saliva cortisol, confirmed that yohimbine + hydrocortisone dosing elicited a significant physiological stress response. These findings support a priori hypotheses and demonstrate that acute stress impairs dlPFC function and excitatory activity. This study highlights a neurobiological mechanism through which acute stress may contribute to psychiatric dysfunction and derail treatment progress. Future research is needed to isolate noradrenaline vs. cortisol effects and evaluate anti-stress medications and/or behavioral interventions.

Risk of incident claims for chemotherapy-induced peripheral neuropathy among women with breast cancer in a Medicare population

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and disabling consequence of neurotoxic therapies, yet factors that modulate the development and clinical impact of CIPN are poorly understood. This epidemiological analysis identifies risk factors for the incidence of CIPN.

METHODS

This retrospective analysis of Surveillance, Epidemiology, and End Results-Medicare data examined predictors of incident CIPN claims among 11,149 women aged 66 years or older with American Joint Commission on Cancer (AJCC) stage II to IV breast cancer (and no secondary cancer diagnosis or preexisting neuropathy) who received chemotherapy.

RESULTS

Overall, new CIPN claims occurred for 8.3% of patients within 1 year of starting chemotherapy. Risk emerged approximately 3 months after the start of chemotherapy and increased throughout 1 year. Paclitaxel as part of first-line therapy increased CIPN risk 2.7-fold in comparison with nonneurotoxic agents (15.9% vs 5.0%), with lower incidence rates for carboplatin and paclitaxel (11.9%), carboplatin and docetaxel (9.3%), carboplatin alone (7.7%), and docetaxel alone (6.6%). The CIPN incidence rate was higher for women who at the time of their breast cancer diagnosis were relatively young (within this Medicare sample), were at AJCC stage II or III, were married or had an equivalent status, and had fewer comorbidities, but it did not differ by race/ethnicity or poverty level.

CONCLUSIONS

These Medicare claims database findings indicate that women aged 66 years or older with breast cancer are susceptible to CIPN from taxane and/or platinum compounds, with risk emerging approximately 3 months into treatment. Prospective studies of symptom emergence and clinical response (eg, stopping chemotherapy and adjunctive treatments) are indicated to determine how best to inform patients of this risk and to manage CIPN in this population.

Anti-stress neuropharmacological mechanisms and targets for addiction treatment: A translational framework

Stress-related substance use is a major challenge for treating substance use disorders. This selective review focuses on emerging pharmacotherapies with potential for reducing stress-potentiated seeking and consumption of nicotine, alcohol, marijuana, cocaine, and opioids (i.e., key phenotypes for the most commonly abused substances). I evaluate neuropharmacological mechanisms in experimental models of drug-maintenance and relapse, which translate more readily to individuals presenting for treatment (who have initiated and progressed). An affective/motivational systems model (three dimensions: valence, arousal, control) is mapped onto a systems biology of addiction approach for addressing this problem. Based on quality of evidence to date, promising first-tier neurochemical receptor targets include: noradrenergic (α1 and β antagonist, α2 agonist), kappa-opioid antagonist, nociceptin antagonist, orexin-1 antagonist, and endocannabinoid modulation (e.g., cannabidiol, FAAH inhibition); second-tier candidates may include corticotropin releasing factor-1 antagonists, serotonergic agents (e.g., 5-HT reuptake inhibitors, 5-HT3 antagonists), glutamatergic agents (e.g., mGluR2/3 agonist/positive allosteric modulator, mGluR5 antagonist/negative allosteric modulator), GABA-promoters (e.g., pregabalin, tiagabine), vasopressin 1b antagonist, NK-1 antagonist, and PPAR-γ agonist (e.g., pioglitazone). To address affective/motivational mechanisms of stress-related substance use, it may be advisable to combine agents with actions at complementary targets for greater efficacy but systematic studies are lacking except for interactions with the noradrenergic system. I note clinically-relevant factors that could mediate/moderate the efficacy of anti-stress therapeutics and identify research gaps that should be pursued. Finally, progress in developing anti-stress medications will depend on use of reliable CNS biomarkers to validate exposure-response relationships.

Factors associated with sedative use and misuse among heroin users

BACKGROUND

Rates of both opioid and sedative use and misuse are rising. Comorbid opioid and sedative use is associated with especially severe consequences (e.g., overdose and poor health outcomes). Heroin users report multiple motivations for sedative use, including self-medication. We aimed to understand differences in lifetime substance use characteristics between heroin users with different sedative use histories.

METHODS

Substance use data were collected from 385 non-treatment seeking heroin users. Subjects were divided into four lifetime sedative-use groups: no use, medical use only, non-medical use only, and mixed medical and non-medical use. We examined patterns of use of various substances of abuse (tobacco, alcohol, marijuana, cocaine, heroin, and sedatives) and individual characteristics associated with each.

RESULTS

Non-medical sedative use (alone or in addition to medical use) was associated with more negative consequences from using all substances. Medical sedative use alone was not related to increased overdose or emergency room visits associated with heroin use. Non-medical sedative use was associated with increases in 15 of the 21 measured heroin consequences and only one of those - health problems - was also associated with medical sedative use.

CONCLUSIONS

Concomitant non-medical sedative use and heroin use is associated with significantly greater negative outcomes than those experienced by heroin users who report use of sedatives only as prescribed. Understanding these differences offers insight into risks related to using both substances and may help treatment providers create targeted harm reduction interventions for this population.

Developing a scale of domains of negative consequences of chronic heroin use

BACKGROUND

Chronic use of heroin typically leads to numerous negative life consequences and serious clinical impairment. Increased negative consequences can result in poor treatment outcomes as well as adverse health effects and impaired social functioning. Certain risk factors, including early substance use initiation, concurrent use of other illicit substances, and injection drug use are associated with an increase in negative consequences. This study examined whether there are unique domains of heroin consequences and, if so, whether these domains are related to specific substance use characteristics.

METHODS

Data regarding substance use characteristics were collected from 370 non-treatment seeking, heroin-using, 18 to 55year-old participants from the Detroit metropolitan area. Principal component analysis (PCA) was used to analyze the factor structure of 21 negative heroin consequence items.

RESULTS

PCA demonstrated that heroin consequences could be divided into 5 unique domains. These unique domains were related to specific substance use characteristics and heroin consequence domains. Injection heroin use was significantly associated with increased Factor 1 consequences (primarily acute medical problems) but not with consequences in other domains. Certain substance use characteristics, such as injection status and earlier onset of marijuana use, were associated with increased consequences in specific domains.

CONCLUSIONS

These findings support the existence of unique domains of negative consequences, and indicate that some risk factors (e.g. injection use) may be specific to these domains. Potential tailored-treatment strategies aimed at improving treatment engagement and reducing harm for heroin use based on person-specific risks and negative consequences are discussed.

Mediational Pathways Among Trait Impulsivity, Heroin-use Consequences, and Current Mood State

BACKGROUND

This study examined whether lifetime heroin-use consequences mediate the relationship between trait impulsivity and three current mood outcomes: depression symptoms, stress levels, and perception of life events.

METHOD

Regular heroin users (N = 163) were assessed using the Barratt Impulsiveness Scale (BIS-11) to measure trait impulsivity; a standardized Drug History and Use Questionnaire to measure lifetime adverse consequences of heroin use; Beck Depression Inventory II to measure current depression symptoms; Stress subscale of the Depression Anxiety Stress scale; and Hassles and Uplifts scale to measure perception of life events.

RESULTS

BIS-11 Attentional and Motor impulsivity were positively related to number of adverse heroin-use consequences, depression symptoms, and stress level, and negatively associated with positive perception of events. A greater number of heroin-use consequences was related to more depression symptoms, higher stress, more negative perception of events, injection heroin use, and earlier ages of first and regular heroin use. In six mediation models, lifetime heroin-use consequences partially mediated relationships between two trait impulsivity domains (Attentional, Motor) and current mood measures (depression symptoms, stress, perception of events).

CONCLUSIONS

The present findings suggest that current negative mood can be a response to the accumulated burden of heroin-use consequences, particularly in the presence of high trait impulsivity.

Baseline risk factors for drug use among African-American patients during first-month induction/stabilization on methadone

Drug use during methadone induction/stabilization negatively influences later methadone-maintenance-treatment [MMT] outcomes (retention, abstinence). Our study examined the association of baseline risk factors to drug use during the first month of methadone treatment as well as longer-term treatment retention. We conducted these analyses among a race/ethnic minority group at high risk for worse MMT outcomes. African-American MMT patients (N=212) were interviewed at intake to assess clinical (drug use history), psychosocial (close family member substance abuse, psychosocial problems), and demographic factors. Outcomes were first-month opioid⁺ and cocaine⁺ urine drug screen [UDS] results and retention (days in treatment). In bivariate analyses, co-occurring cocaine abuse/dependence was associated with worse outcomes for opioid⁺ UDS, cocaine⁺ UDS, and retention. Being a primary injection opioid user and residing farther from the clinic were associated with a higher proportion of cocaine⁺ UDS and shorter retention, respectively. Patients with a significant other substance abuse history provided a higher proportion of both opioid⁺ and cocaine⁺ UDS. Sibling and parent substance abuse histories were associated with a higher proportion of opioid⁺ UDS and shorter retention. Psychosocial problems (economic, housing) were associated with a higher proportion of cocaine⁺ UDS. In multivariate analyses, co-occurring cocaine abuse/dependence and primary injection opioid use best accounted for first-month opioid⁺ and cocaine⁺ UDS, respectively. A higher proportion of first-month opioid⁺ and cocaine⁺ UDS and living farther from the clinic accounted for retention. African-American patients reporting baseline risk factors (particularly clinical) experience worse short- and long-term MMT outcomes. Recommendations for improving standards of care are discussed.

A pilot randomized clinical trial of an intervention to reduce overdose risk behaviors among emergency department patients at risk for prescription opioid overdose

BACKGROUND AND AIMS

Prescription opioid overdose is a significant public health problem. Interventions to prevent overdose risk behaviors among high-risk patients are lacking. This study examined the impact of a motivational intervention to reduce opioid misuse and overdose risk behaviors.

METHODS

This study was a pilot randomized controlled trial set in a single emergency department (ED) in which, 204 adult, English-speaking patients seeking care who reported prescription opioid misuse during the prior 3 months were recruited. Patients were randomized to either the intervention, a 30-minute motivational interviewing-based session delivered by a therapist plus educational enhanced usual care (EUC), or EUC alone. Participants completed self-reported surveys at baseline and 6 months post-baseline (87% retention rate) to measure the primary outcomes of overdose risk behaviors and the secondary outcome of non-medical opioid use.

FINDINGS

Participants in the intervention condition reported significantly lower levels of overdose risk behaviors (incidence rate ratio [IRR]=0.72, 95% CI: 0.59-0.87; 40.5% reduction in mean vs. 14.7%) and lower levels of non-medical opioid use (IRR=0.81, 95% CI: 0.70-0.92; 50.0% reduction in mean vs. 39.5%) at follow-up compared to the EUC condition.

CONCLUSIONS

This study represents the first clinical trial of a behavioral intervention to reduce overdose risk. Results indicate that this single motivational enhancement session reduced prescription opioid overdose risk behaviors, including opioid misuse, among adult patients in the ED.

Parental Support, Mental Health, and Alcohol and Marijuana Use in National and High-Risk African-American Adolescent Samples

African-American adolescents experience disproportionate rates of negative consequences of substance use despite using substances at average or below-average rates. Due to underrepresentation of African-American adolescents in etiological literature, risk and protective processes associated with their substance use require further study. This study examines the role of parental support in adolescents' conduct problems (CPs), depressive symptoms (DSs), and alcohol and marijuana use in a national sample and a high-risk sample of African-American adolescents. In both samples, parental support was inversely related to adolescent CPs, DSs, and alcohol and marijuana use. CPs, but not DSs, partially mediated the relation of parental support to substance use. Results were consistent across the national and high-risk samples, suggesting that the protective effect of parental support applies to African-American adolescents from a range of demographic backgrounds.

Heroin delay discounting: Modulation by pharmacological state, drug-use impulsivity, and intelligence

Delay discounting (DD) refers to how rapidly an individual devalues goods based on delays to receipt. DD usually is considered a trait variable but can be state dependent, yet few studies have assessed commodity valuation at short, naturalistically relevant time intervals that might enable state-dependent analysis. This study aimed to determine whether drug-use impulsivity and intelligence influence heroin DD at short (ecologically relevant) delays during two pharmacological states (heroin satiation and withdrawal). Out-of-treatment, intensive heroin users (n = 170; 53.5% African American; 66.7% male) provided complete DD data during imagined heroin satiation and withdrawal. Delays were 3, 6, 12, 24, 48, 72, and 96 hours; maximum delayed heroin amount was thirty $10 bags. Indifference points were used to calculate area under the curve (AUC). We also assessed drug-use impulsivity (subscales from the Impulsive Relapse Questionnaire [IRQ]) and estimated intelligence (Shipley IQ) as predictors of DD. Heroin discounting was greater (smaller AUC) during withdrawal than satiation. In regression analyses, lower intelligence and IRQ Capacity for Delay as well as higher IRQ Speed (to return to drug use) predicted greater heroin discounting in the satiation condition. Lower intelligence and higher IRQ Speed predicted greater discounting in the withdrawal condition. Sex, race, substance use variables, and other IRQ subscales were not significantly related to the withdrawal or satiation DD behavior. In summary, heroin discounting was temporally rapid, pharmacologically state dependent, and predicted by drug-use impulsivity and estimated intelligence. These findings highlight a novel and sensitive measure of acute DD that is easy to administer.