Cocaine dependence and concurrent marijuana use: a comparison of clinical characteristics

Laboratory method to induce state boredom increases impulsive choice in people who use cocaine and controls

Background: Impulsive choice is associated with both cocaine use and relapse. Little is known about the influence of transient states on impulsive choice in people who use cocaine (PWUC).Objective: This study investigated the direct effects of induced boredom on impulsive choice (i.e., temporal discounting) in PWUC relative to well-matched community controls.Methods: Forty-one PWUC (≥1× cocaine use in past 3 months; 7 females) and 38 demographically matched controls (5 females) underwent two experimental conditions in counterbalanced order. Temporal discounting was assessed immediately after a standardized boredom induction task (peg-turning) and a self-selected video watched for the same duration (non-boredom). Subjective mood state and perceived task characteristics were assessed at baseline, during experimental manipulations, and after the choice task.Results: PWUC and controls were well matched on sex, age, and socioeconomic status. Groups were also similar in reported use of drugs other than cocaine, except for recent cigarette and alcohol use (PWUC > controls). As expected, peg-turning increased boredom in the sample overall, with higher boredom reported during peg-turning than the video (p < .001, η2p = .20). Participants overall exhibited greater impulsive choice after boredom than non-boredom (p = .028, η2p = .07), with no preferential effects in PWUC (p > .05, BF01 = 2.9).Conclusion: Experimentally induced boredom increased state impulsivity irrespective of cocaine use status - in PWUC and carefully matched controls - suggesting a broad link between boredom and impulsive choice. This is the first study to show that transient boredom directly increases impulsive choice. Data support a viable laboratory method to further parse the effects of boredom on impulsive choice.

Cannabis use to manage stimulant cravings among people who use unregulated drugs

BACKGROUND

We sought to analyze the association between cannabis use to manage stimulant cravings and self-reported changes in stimulant use among structurally marginalized people who use unregulated drugs (PWUD).

METHODS

The data for this secondary analysis was collected from a cross-sectional questionnaire administered to people who concurrently use cannabis and unregulated stimulants in Vancouver, Canada. We used logistic regression models to analyze the association between cannabis use to manage stimulant cravings and self-reported changes in the frequency of stimulant use.

RESULTS

In total, 297 individuals were included in the present study. Cannabis use to manage stimulant cravings was reported by 134 (45.1 %) participants and 104 (77.6 %) of these participants reported decreasing their stimulant use during periods of cannabis use. In the multivariable logistic regression analysis, cannabis use to manage stimulant cravings (adjusted Odds Ratio [aOR] = 0.24, 95 % confidence interval [CI]: 0.10, 0.56) was significantly associated with self-reported reductions in stimulant use. In the sub-analyses, cannabis use to manage stimulant cravings was significantly associated with reduced stimulant use among people who used crystal methamphetamine daily (aOR = 0.08, 95 % CI: 0.02-0.37) and was not significantly associated with reduced stimulant use among people who used crack/cocaine daily (aOR = 0.33, 95 % CI: 0.04-2.86).

CONCLUSIONS

These findings indicate that cannabis use to manage stimulant cravings is a common harm reduction strategy and suggest that this may be an effective strategy to reduce stimulant use among some PWUD.

Smoked cannabis reduces peak cocaine plasma levels and subjective effects in a controlled drug administration study of polysubstance use in men

BACKGROUND

Despite the high prevalence of polysubstance use, outcomes and potential risks associated with common drug combinations are not well characterized. Many individuals who use cocaine also use cannabis, yet little is known about how interactions between the two drugs might contribute to continued co-use.

METHODS

The aim of this double-blind, placebo-controlled study was to determine the physiological and subjective effects of smoked cannabis with smoked cocaine, to identify variables that may contribute to the continued use of this drug combination. Healthy, non-treatment seeking volunteers who reported smoking both cocaine and cannabis (N = 9, all males) completed a 13-day inpatient protocol. On session days, cannabis [0.0 or 5.6 % tetrahydrocannabinol (THC)] was administered 28 min prior to cocaine (0, 12, or 25 mg). Dependent measures included pharmacokinetic assessment of THC and cocaine and their respective metabolites, in addition to subjective and cardiovascular effects.

RESULTS

Active cannabis (5.6 % THC) increased plasma levels of THC and the metabolite 11-nor-9-carboxy-Δ9-THC (THCCOOH), as well as subjective ratings of cannabis effects and heart rate relative to inactive cannabis. Cocaine dose-dependently increased plasma cocaine and metabolites and subjective ratings of cocaine effects. Active cannabis pre-treatment decreased plasma levels of cocaine and metabolites. Furthermore, active cannabis attenuated cocaine-related reductions in 'Hunger' and 'Calm.'

CONCLUSIONS

Cannabis pre-treatment altered the subjective experience of smoked cocaine and reduced peak plasma levels of cocaine. Future studies should explore additional doses of each drug and whether these changes also impact cocaine's reinforcing effects.

The impact of marijuana use on cocaine use outcomes among patients in methadone maintenance treatment across five trials of contingency management

OBJECTIVE

Cocaine use is prevalent among patients in methadone maintenance and a risk factor for poor treatment outcomes. Contingency management (CM) decreases cocaine use in this population, but little is known about its efficacy when marijuana use is present prior to or during treatment.

METHOD

Data from five randomized CM trials (N = 557) were used to evaluate whether: (a) marijuana frequency (none, low, or high) prior to or during treatment impacts cocaine use outcomes and (b) marijuana use differentially impacts cocaine outcomes with standard care (SC) + CM versus SC alone.

RESULTS

Relative to no marijuana use, low (β = .28, p < .01) and high marijuana use (β = .32, p < .05) during treatment were associated with roughly 1 week shorter duration of cocaine abstinence on average. Low marijuana use (β = .71, p < .05) during treatment was associated with a lower proportion of negative cocaine samples during treatment relative to no marijuana use. Treatment group by marijuana use (before or during treatment) interactions on duration and proportion of cocaine abstinence during treatment were not significant. For longer term outcomes, in SC + CM, marijuana use during treatment did not impact cocaine abstinence 6 months post-baseline. In SC, low (OR = .44, p < .05) and high (OR = .26, p < .001) marijuana use during treatment decreased odds of cocaine abstinence at 6 months post-baseline relative to no use.

CONCLUSIONS

Findings highlight the benefits of SC + CM and abstaining from marijuana use during active treatment. At 6 months postbaseline, SC + CM evidenced similar cocaine abstinence regardless of marijuana use levels during treatment, while those with low and high marijuana use showed decreased abstinence rates in SC only. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Co-exposure of cocaine and cannabinoids and its association with select biological, behavioural and health outcomes: A systematic scoping review of multi-disciplinary studies

Cocaine use entails severe health- and social-related harms globally. Treatment options for cocaine dependence are highly limited. Benefits of cannabinoids for addiction have been documented, making it opportune to examine existing data on the possible outcomes associated with cannabinoids and cocaine co-use. We conducted a systematic scoping review following the PRISMA guidelines of peer-reviewed, English-language studies published from 2000 to 2021 in four databases (Medline, Web-of-Science, CINAHL Plus, and PsycInfo), assessing the co-exposure of cannabis/cannabinoids with cocaine on behavioural, biological or health outcomes. Both quantitative and qualitative, as well as humans and pre-clinical animals' studies (n=46) were included. Pre-clinical studies (n=19) showed mostly protective effects of cannabidiol (CBD) administration on animal models of addiction (e.g., cocaine-craving, -relapse, and -withdrawal) and cocaine-toxicity. Tetrahydrocannabinol (THC) had more inconsistent results, with both protective and counter-protective effects. Human studies (n=27) were more heterogeneous and assessed natural ongoing cannabis and cocaine use or dependence. Quantitative-based studies showed mostly enhanced harms in several outcomes (e.g., cocaine use, mental health); two available clinical trials found no effect upon CBD administration on cocaine-related treatment outcomes. Qualitative data-based studies reported cannabis use as a substitute for or to alleviate harms of crack-cocaine use. While pre-clinical studies suggest a potential of cannabinoids, especially CBD, to treat cocaine addiction, the few trials conducted in humans found no benefits. Cannabis co-use by cocaine users commonly presents a risk factor, entailing enhanced harms for users. More rigorous, controlled trials are still necessary to investigate cannabinoids' potential considering pre-clinical findings and reported benefits from specific drug users.

Marijuana Use and In-Hospital Outcomes After Percutaneous Coronary Intervention in Michigan, United States

OBJECTIVES

The aim of this study was to evaluate the association between reported marijuana use and post-percutaneous coronary intervention (PCI) in-hospital outcomes.

BACKGROUND

Marijuana use is increasing as more states in the United States legalize its use for recreational and medicinal purposes. Little is known about the frequency of use and relative safety of marijuana among patients presenting for PCI.

METHODS

The authors analyzed Blue Cross Blue Shield of Michigan Cardiovascular Consortium PCI registry data between January 1, 2013, and September 30, 2016. One-to-one propensity matching and multivariable logistic regression were used to adjust for differences between patients with or without reported marijuana use, and rates of post-PCI complications were compared.

RESULTS

Among 113,477 patients, 3,970 reported marijuana use. Compared with those without reported marijuana use, patients with reported marijuana use were likely to be younger (53.9 years vs 65.8 years), to use tobacco (73.0% vs 26.8%), to present with ST-segment elevation myocardial infarction (27.3% vs 15.9%), and to have fewer cardiovascular comorbidities. After matching, compared with patients without reported marijuana use, those with reported marijuana use experienced significantly higher risks for bleeding (adjusted odds ratio [aOR]: 1.54; 95% confidence interval [CI]: 1.20-1.97; P < 0.001) and cerebrovascular accident (aOR: 11.01; 95% CI: 1.32-91.67; P = 0.026) and a lower risk for acute kidney injury (aOR: 0.61; 95% CI: 0.42-0.87; P = 0.007). There were no significant differences in risks for transfusion and death.

CONCLUSIONS

A modest fraction of patients undergoing PCI used marijuana. Reported marijuana use was associated with higher risks for cerebrovascular accident and bleeding and a lower risk for acute kidney injury after PCI. Clinicians and patients should be aware of the higher risk for post-PCI complications in these patients.

Association Between Recent Cannabis Consumption and Withdrawal-Related Symptoms During Early Abstinence Among Females With Smoked Cocaine Use Disorder

BACKGROUND

The effects of cannabis on clinical outcomes of treatment services for other drug use disorders remains unclear. The primary aim of the current study was to investigate the effects of recent cannabis consumption on the severity of cocaine withdrawal and depressive symptoms during a 3-week inpatient treatment program for women with cocaine use disorder. The second goal of this study was to test the effect of recent alcohol or tobacco use on the aforementioned outcomes.

METHODS

This was a longitudinal study with 2 assessment time points: at enrollment and upon discharge from a medically managed intensive inpatient unit. The sample was composed of 214 early abstinence females with cocaine use disorder. Cocaine withdrawal and depressive symptoms were measured using the Cocaine Selective Severity Assessment (CSSA) and the Beck Depressive Inventory (BDI-II). Recent substance use was evaluated using the Addiction Severity Index (ASI-6).

RESULTS

Patients with cocaine use disorder and with frequent recent cannabis use reported higher severity of cocaine withdrawal and depressive symptoms after 3 weeks of inpatient treatment. Neither recent alcohol nor tobacco use was associated with increased CSSA or BDI outcomes, suggesting these substances play a minor role compared to recent cannabis use in affecting withdrawal-related symptoms.

CONCLUSIONS

The assessment of recent cannabis use may help identify patients in need of additional treatment to manage severe cocaine withdrawal symptoms and depressive symptoms during early abstinence.

Cocaine and Marijuana Polysubstance Use and Cocaine Use Disorder: Investigating Mediated Effects through Patterns of Cocaine Use

Cocaine use is on the rise and it is comorbid with marijuana use. We examined the association between lifetime cocaine + marijuana polysubstance use (CM PSU) versus cocaine only and lifetime cocaine use disorder (CocUD) and examined the potential mediation by cocaine use patterns. Methods: A total of 2,968 lifetime cocaine users were identified from the National Epidemiologic Survey on Alcohol and Related Conditions-III. Mediation analysis was utilized to examine cocaine use quantity, frequency, and duration as potential mediators in the association between CM PSU and CocUD. A parallel multiple mediator model and a structural equation model were used, respectively, to examine: (1) the individual contribution of cocaine use quantity, frequency, and duration, and (2) combined contribution as a set specified by a latent variable. Results: Cocaine users were divided into 2,782 (93.7%) CM polysubstance users and 186 (6.3%) cocaine only users. CM PSU was associated with decreased risk of CocUD, but after including the mediators, the association was no longer significant. Examined separately, only quantity was found to be a significant mediator over and above frequency and duration, while the latent variable with three cocaine use pattern indicators explained 56.6% of the total association between CM PSU and CocUD. Conclusions: Compared to cocaine only users, CM polysubstance users were less likely to use cocaine heavily; this lower intensity of cocaine use was in turn associated with decreased risk of CocUD. Future research is warranted to determine the nature of the association between CM PSU and reduced CocUD.

Effect of chronic cocaine use on fine motor coordination tested during ophthalmic vitreoretinal simulated performance

We conducted a case-control study using the Eyesi simulator to assess the surgical performance of 24 chronic cocaine users (CCUs) and 24 sex-/age-matched controls to numerically quantify ophthalmic microsurgical simulator performance and fine motor deficiencies. The inclusion criteria were no exposure to illicit drugs other than cocaine, marijuana, or alcohol within the previous month and no health conditions that could impact manual task performance. The outcomes included surgical scores (0-100, worst-best) and task completion time (minutes). Fisher's exact test, analysis of variance, Mann-Whitney U test, and Kruskal-Wallis test followed by Dunn-Bonferroni post-hoc were conducted for statistical analysis. The Eyesi scores were lower among CCUs compared to controls for bimanual tasks (4.50 ± 14.30 vs. 18.46 ± 26.64, p = 0.012), for exercises demanding upper and lower limb coordination (both hands and two foot pedals, respectively) (74.13 ± 35.01 vs. 85.21 ± 24.1, p = 0.045), and in the overall score for all three tasks (27.38 ± 15.06 vs. 39.5 ± 18.66, p = 0.021). CCUs took longer to complete tasks when performing exercises demanding upper and lower limb coordination compared to controls (1.26 ± 0.38 vs. 1.02 ± 0.44 min, p = 0.006). Individuals who used cocaine during the previous month had an independent lower bimanual score compared to controls (1.42 ± 4.91 vs. 18.46 ± 26.64, p = 0.018). No differences in performance among the CCUs were attributable to sporadic cannabis or alcohol use. Chronic use of cocaine negatively impacted fine dexterity as measured by bimanual tasks or maneuvers that required simultaneous coordination of the upper and lower limbs. This was most notable among individuals who used cocaine during the 1-month period before the simulation.

Cognitive dysfunction in individuals with cocaine use disorder: Potential moderating factors and pharmacological treatments

It is well-documented in the literature that individuals repeatedly exposed to cocaine exhibit cognitive impairment and that cognitive dysfunction is a risk factor for poor treatment outcomes in those with cocaine use disorder (CUD). Specific deficits related to attention, episodic memory, working memory, and executive functioning are the most common deficits noted in this population. Given that cognitive impairment is a risk factor for poor treatment outcomes in those with CUD, identifying possible moderating factors contributing to and/or exacerbating cocaine-related cognitive deficits is of great importance. Some of these factors may include premorbid intellectual functioning, cocaine use patterns, polysubstance use, comorbid emotional symptoms, and sleep dysfunction. It is plausible that by identifying moderating factors impacting cognition, behavioral interventions can then be modified accordingly and/or treatment regimens can be augmented with pharmacological interventions (e.g., cognitive enhancing agents), leading to a reduction in treatment attrition and improved treatment outcomes. The currently available treatments for CUD are mainly behavioral with variable efficacy, and even though there have been great preclinical and clinical research efforts focused on medication development for CUD, there are currently no Food and Drug Administration-approved medications for CUD. A description of some of the several potential moderating factors, along with some pharmacological treatments which have been shown to ameliorate, at least to some extent, cognitive dysfunction in those with CUD are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Blunted Frontostriatal Blood Oxygen Level-Dependent Signals Predict Stimulant and Marijuana Use

BACKGROUND

Occasional recreational stimulant (amphetamine and cocaine) use is an important public health problem among young adults because 16% of those who experiment develop stimulant use disorder. This study aimed to determine whether behavioral and/or neural processing measures can forecast the transition from occasional to problematic stimulant use.

METHODS

Occasional stimulant users completed a Risky Gains Task during functional magnetic resonance imaging and were followed up 3 years later. Categorical analyses tested whether blood oxygen level-dependent (BOLD) responses differentiated occasional stimulant users who became problem stimulant users (n = 35) from those who desisted from stimulant use (n = 75) at follow-up. Dimensional analyses (regardless of problem stimulant user or desisted stimulant use status; n = 144) tested whether BOLD responses predicted baseline and follow-up stimulant and marijuana use.

RESULTS

Categorical results indicated that relative to those who desisted from stimulant use, problem stimulant users 1) made riskier decisions after winning feedback; 2) exhibited lower frontal, insular, and striatal BOLD responses to win/loss feedback after making risky decisions; and 3) displayed lower thalamic but greater temporo-occipital BOLD responses to risky losses than to risky wins. In comparison, dimensional results indicated that lower BOLD signals to risky choices than to safe choices in frontal, striatal, and additional regions predicted greater marijuana use at follow-up.

CONCLUSIONS

Taken together, blunted frontostriatal signals during risky choices may quantify vulnerability to future marijuana consumption, whereas blunted frontostriatal signals to risky outcomes mark risk for future stimulant use disorder. These behavioral and neural processing measures may prove to be useful for identifying ultra-high risk individuals prior to onset of problem drug use.

The importance of considering polysubstance use: lessons from cocaine research

BACKGROUND

Polysubstance use (PSU) is prevalent among individuals with substance use disorders, but the vast majority of preclinical substance use research has focused on individual substances in isolation. Cocaine has been prevalent in the repertoire of persons who use more than one illicit substance.

METHODS

We conducted a meta-analysis combining results from literature searches and secondary data analyses to estimate the prevalence of simultaneous and concurrent cocaine + alcohol and cocaine + cannabis use among cocaine users. We next summarized the small body of literature on behavioral, cognitive and neurobiological consequences of cocaine PSU across species, with a focus on alcohol and cannabis. Finally, we used systematic literature searches to assess the extent to which human and animal studies on the neurobiological consequences of cocaine include PSU subjects.

RESULTS

The estimated prevalence of simultaneous and concurrent alcohol use among human cocaine users was 74% and 77%, respectively. The estimated prevalence of simultaneous and concurrent cannabis use among cocaine users was 38% and 64%, respectively. Consumption of alcohol or cannabis with cocaine enhances subjective responses to cocaine, concomitant with changes in cocaine metabolism that increase blood cocaine levels, and, in the case of alcohol, produce the psychoactive metabolite cocaethylene. There is also consistent evidence for neurobiological effects of cocaine + alcohol combinations. However, animal PSU research with cocaine lags behind human research.

CONCLUSION

Based on the prevalence and known consequences of PSU, consideration of PSU in both human and animal research is vital for understanding patterns of substance use.

Exposure to Advertisements and Marijuana Use Among US Adolescents

Introduction

This study examined whether exposure to marijuana advertisements was associated with current marijuana use and frequency of use among US adolescents in grades 8, 10, and 12.

Methods

Weighted estimates of exposure to marijuana advertisements and marijuana use from the 2014 and 2015 Monitoring the Future studies were investigated. Factors associated with the prevalence and frequency of marijuana use were analyzed by using logistic regression and linear regression models, respectively.

Results

Of all respondents (n = 12,988), 13.8% reported marijuana use in the past 30 days. Exposure to marijuana advertisements was prevalent among adolescents, with 52.8% reporting exposure from internet advertisements, 32.1% from television advertisements, 24.1% from magazine or newspaper advertisements, 19.7% from radio advertisements, 19.0% from advertisements on storefronts, and 16.6% from billboards. In the multivariable analysis, current use of marijuana among adolescents was associated with exposure to marijuana advertisements on storefronts (adjusted odds ratio [OR] = 1.4, P < .001), magazines or newspapers (adjusted OR = 1.6, P < .001), billboards (adjusted OR = 1.4, P = .002), internet (adjusted OR = 1.8, P < .001), television (adjusted OR = 1.4, P < .001) and radio (adjusted OR = 1.7, P < .001). Exposure to marijuana advertisements from the internet was associated with increased use of marijuana (β = 0.3, P = .04).

Conclusion

Exposure to marijuana advertisements was associated with higher odds of current marijuana use among adolescents. Regulations that limit marijuana advertisements to adolescents and educational campaigns on harmfulness of illicit marijuana use are needed.

Demographic and clinical characteristics of treatment seeking women with full and subthreshold PTSD and concurrent cannabis and cocaine use disorders

While the detrimental effects of concurrent substance use disorders (SUDs) are now being well documented, very few studies have examined this comorbidity among women with posttraumatic stress disorder (PTSD). Data for these analyses were derived from the "Women and Trauma" study conducted within the National Drug Abuse Treatment Clinical Trials Network. Women with full or subthreshold PTSD and co-occurring cannabis use disorder (CUD) and cocaine use disorder (COD; N=99) were compared to their counterparts with co-occurring CUD only (N=26) and co-occurring COD only (N=161) on rates of trauma exposure, psychiatric disorders, psychosocial problems, and other substance use utilizing a set of multivariate logistic regressions. In models adjusted for age and race/ethnicity, women with PTSD and COD only were significantly older than their counterparts with CUD only and concurrent CUD+COD. Relative to those with CUD only, women with concurrent CUD+COD had higher odds of adult sexual assault. Relative to those with COD only, women with concurrent CUD+COD had higher odds of alcohol use disorder in the past 12months. Finally, relative to those with CUD only, women with COD only had higher odds of ever being arrested/convicted and adult sexual assault. The higher rates of adult sexual assault and alcohol use disorder among those with concurrent CUD+COD suggest the need for trauma-informed approaches that can respond to the needs of this dually-diagnosed population. Moreover, the causal link between repeated traumatic stress exposure and polysubstance use requires further examination.

Impact of Cannabis Use on Treatment Outcomes among Adults Receiving Cognitive-Behavioral Treatment for PTSD and Substance Use Disorders

BACKGROUND

Research has demonstrated a strong link between trauma, posttraumatic stress disorder PTSD and substance use disorders (SUDs) in general and cannabis use disorders in particular. Yet, few studies have examined the impact of cannabis use on treatment outcomes for individuals with co-occurring PTSD and SUDs.

METHODS

Participants were 136 individuals who received cognitive-behavioral therapies for co-occurring PTSD and SUD. Multivariate regressions were utilized to examine the associations between baseline cannabis use and end-of-treatment outcomes. Multilevel linear growth models were fit to the data to examine the cross-lagged associations between weekly cannabis use and weekly PTSD symptom severity and primary substance use during treatment.

RESULTS

There were no significant positive nor negative associations between baseline cannabis use and end-of-treatment PTSD symptom severity and days of primary substance use. Cross-lagged models revealed that as cannabis use increased, subsequent primary substance use decreased and vice versa. Moreover, results revealed a crossover lagged effect, whereby higher cannabis use was associated with greater PTSD symptom severity early in treatment, but lower weekly PTSD symptom severity later in treatment.

CONCLUSION

Cannabis use was not associated with adverse outcomes in end-of-treatment PTSD and primary substance use, suggesting independent pathways of change. The theoretical and clinical implications of the reciprocal associations between weekly cannabis use and subsequent PTSD and primary substance use symptoms during treatment are discussed.

Marijuana and Other Substance Use Among Motor Vehicle Operators: A Latent Class Analysis

OBJECTIVE

The deleterious effect of multiple-substance use on driving performance is well established, but relatively little research has examined the patterns of drug use among multiple-substance users and its relationship to both alcohol use and adverse driving outcomes.

METHOD

The current study used latent class analysis to examine subgroups of substance users among a population of drivers who screened positively for 2 or more of 13 substances other than alcohol (N = 250). A series of logistic regression analyses was conducted to examine demographic predictors of latent class assignment and class association with adverse driving outcomes.

RESULTS

Four distinct subclasses of users were identified among multiple-substance-using drivers: Class 1 consisted of individuals who demonstrated high levels of all substances indicators (5%). The second class demonstrated high levels of marijuana and cocaine use and lower levels of all other substances (27%). The third class screened high for marijuana and nonmedical prescription opiate analgesics use (36%), whereas the last class demonstrated high nonmedical prescription opiate analgesics and benzodiazepine use (32%). Drivers in Class 2 (marijuana and cocaine users) were more likely to be younger and have a positive breath alcohol concentration than drivers in any other class.

CONCLUSIONS

Because multidrug users show dissimilar characteristics, the propensity of researchers to lump all multiple-substance users together may either erroneously attribute the potentially profound impact of those in the marijuana and cocaine use class to all multiple-substance users or dilute their specific contribution to crash risk.

Utility of Machine-Learning Approaches to Identify Behavioral Markers for Substance Use Disorders: Impulsivity Dimensions as Predictors of Current Cocaine Dependence

BACKGROUND

Identifying objective and accurate markers of cocaine dependence (CD) can innovate its prevention and treatment. Existing evidence suggests that CD is characterized by a wide range of cognitive deficits, most notably by increased impulsivity. Impulsivity is multidimensional and it is unclear which of its various dimensions would have the highest predictive utility for CD. The machine-learning approach is highly promising for discovering predictive markers of disease. Here, we used machine learning to identify multivariate predictive patterns of impulsivity phenotypes that can accurately classify individuals with CD.

METHODS

Current cocaine-dependent users (N = 31) and healthy controls (N = 23) completed the self-report Barratt Impulsiveness Scale-11 and five neurocognitive tasks indexing different dimensions of impulsivity: (1) Immediate Memory Task (IMT), (2) Stop-Signal Task, (3) Delay-Discounting Task (DDT), (4) Iowa Gambling Task (IGT), and (5) Probabilistic Reversal-Learning task. We applied a machine-learning algorithm to all impulsivity measures.

RESULTS

Machine learning accurately classified individuals with CD and predictions were generalizable to new samples (area under the curve of the receiver-operating characteristic curve was 0.912 in the test set). CD membership was predicted by higher scores on motor and non-planning trait impulsivity, poor response inhibition, and discriminability on the IMT, higher delay discounting on the DDT, and poor decision making on the IGT.

CONCLUSION

Our results suggest that multivariate behavioral impulsivity phenotypes can predict CD with high degree of accuracy, which can potentially be used to assess individuals' vulnerability to CD in clinical settings.

Anti-saccade error rates as a measure of attentional bias in cocaine dependent subjects

Cocaine-dependent (CD) subjects show attentional bias toward cocaine-related cues, and this form of cue-reactivity may be predictive of craving and relapse. Attentional bias has previously been assessed by models that present drug-relevant stimuli and measure physiological and behavioral reactivity (often reaction time). Studies of several CNS diseases outside of substance use disorders consistently report anti-saccade deficits, suggesting a compromise in the interplay between higher-order cortical processes in voluntary eye control (i.e., anti-saccades) and reflexive saccades driven more by involuntary midbrain perceptual input (i.e., pro-saccades). Here, we describe a novel attentional-bias task developed by using measurements of saccadic eye movements in the presence of cocaine-specific stimuli, combining previously unique research domains to capitalize on their respective experimental and conceptual strengths. CD subjects (N = 46) and healthy controls (N = 41) were tested on blocks of pro-saccade and anti-saccade trials featuring cocaine and neutral stimuli (pictures). Analyses of eye-movement data indicated (1) greater overall anti-saccade errors in the CD group; (2) greater attentional bias in CD subjects as measured by anti-saccade errors to cocaine-specific (relative to neutral) stimuli; and (3) no differences in pro-saccade error rates. Attentional bias was correlated with scores on the obsessive-compulsive cocaine scale. The results demonstrate increased saliency and differential attentional to cocaine cues by the CD group. The assay provides a sensitive index of saccadic (visual inhibitory) control, a specific index of attentional bias to drug-relevant cues, and preliminary insight into the visual circuitry that may contribute to drug-specific cue reactivity.

Prevalence of traumatic brain injury in cocaine-dependent research volunteers

BACKGROUND

There is a high prevalence of traumatic brain injury (TBI) among those with substance dependence. However, TBI often remains undiagnosed in these individuals, due to lack of routine screening in substance use treatment settings or due to overlap in some of the cognitive sequelae (eg impulsivity, disinhibition) of TBI and cocaine dependence.

METHODS

The prevalence of self-reported mild to moderate TBI in a group of cocaine-dependent (n = 95) and a group of healthy volunteers (n = 75) enrolled at the same facility was assessed. Additionally, the relationship between TBI and clinically relevant correlates, including impulsivity, cocaine use history, and treatment outcome in the cocaine-dependent group was also examined.

RESULTS

A higher proportion of individuals with cocaine dependence (29.5%) reported having suffered a TBI in their lifetime compared to controls (8%) on a Closed Head Injury scale. Among cocaine users, the average age of sustaining TBI was significantly lower than the age of initiating cocaine use. Presence of TBI was not associated with higher impulsivity on the Barratt Impulsiveness Scale-11 or self-reported years of cocaine use. No differences were noted on treatment outcome for cocaine dependence as measured by treatment effectiveness scores (TES) between cocaine users with TBI and their non-TBI counterparts.

CONCLUSIONS

These results are the first to highlight the high prevalence of TBI among individuals with cocaine dependence. This study underscores the possible role of TBI history as a risk factor for onset of cocaine use, however, more research is needed to determine the impact of co-morbid TBI as a complicating factor in the substance abuse treatment setting.

Prescribing smoked cannabis for chronic noncancer pain: preliminary recommendations

OBJECTIVE

To offer preliminary guidance on prescribing smoked cannabis for chronic pain before the release of formal guidelines.

QUALITY OF EVIDENCE

We reviewed the literature on the analgesic effectiveness of smoked cannabis and the harms of medical and recreational cannabis use. We developed recommendations on indications, contraindications, precautions, and dosing of smoked cannabis, and categorized the recommendations based on levels of evidence. Evidence is mostly level II (well conducted observational studies) and III (expert opinion).

MAIN MESSAGE

Smoked cannabis might be indicated for patients with severe neuropathic pain conditions who have not responded to adequate trials of pharmaceutical cannabinoids and standard analgesics (level II evidence). Smoked cannabis is contraindicated in patients who are 25 years of age or younger (level II evidence); who have a current, past, or strong family history of psychosis (level II evidence); who have a current or past cannabis use disorder (level III evidence); who have a current substance use disorder (level III evidence); who have cardiovascular or respiratory disease (level III evidence); or who are pregnant or planning to become pregnant (level II evidence). It should be used with caution in patients who smoke tobacco (level II evidence), who are at increased risk of cardiovascular disease (level III evidence), who have anxiety or mood disorders (level II evidence), or who are taking higher doses of opioids or benzodiazepines (level III evidence). Cannabis users should be advised not to drive for at least 3 to 4 hours after smoking, for at least 6 hours after oral ingestion, and for at least 8 hours if they experience a subjective "high" (level II evidence). The maximum recommended dose is 1 inhalation 4 times per day (approximately 400 mg per day) of dried cannabis containing 9% delta-9-tetrahydrocannabinol (level III evidence). Physicians should avoid referring patients to "cannabinoid" clinics (level III evidence).

CONCLUSION

Future guidelines should be based on systematic review of the literature on the safety and effectiveness of smoked cannabis. Further research is needed on the effectiveness and long-term safety of smoked cannabis compared with pharmaceutical cannabinoids, opioids, and other standard analgesics.

Testing the drug substitution switching-addictions hypothesis. A prospective study in a nationally representative sample

IMPORTANCE

Adults who remit from a substance use disorder (SUD) are often thought to be at increased risk for developing another SUD. A greater understanding of the prevalence and risk factors for drug substitution would inform clinical monitoring and management.

OBJECTIVE

To determine whether remission from an SUD increases the risk of onset of a new SUD after a 3-year follow-up compared with lack of remission from an SUD and whether sociodemographic characteristics and psychiatric disorders, including personality disorders, independently predict a new-onset SUD.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study where data were drawn from a nationally representative sample of 34 653 adults from the National Epidemiologic Survey on Alcohol and Related Conditions. Participants were interviewed twice, 3 years apart (wave 1, 2001-2002; wave 2, 2004-2005).

MAIN OUTCOMES AND MEASURES

We compared new-onset SUDs among individuals with at least 1 current SUD at wave 1 who did not remit from any SUDs at wave 2 (n = 3275) and among individuals with at least 1 current SUD at wave 1 who remitted at wave 2 (n = 2741).

RESULTS

Approximately one-fifth (n = 2741) of the total sample had developed a new-onset SUD at the wave 2 assessment. Individuals who remitted from 1 SUD during this period were significantly less likely than those who did not remit to develop a new SUD (13.1% vs 27.2%, P < .001). Results were robust to sample specification. An exception was that remission from a drug use disorder increased the odds of a new SUD (odds ratio [OR] = 1.46; 95% CI, 1.11-1.92). However, after adjusting for the number of SUDs at baseline, remission from drug use disorders decreased the odds of a new-onset SUD (OR = 0.66; 95% CI, 0.46-0.95) whereas the number of baseline SUDs increased those odds (OR=1.68; 95% CI, 1.43-1.98). Being male, younger in age, never married, having an earlier age at substance use onset, and psychiatric comorbidity significantly increased the odds of a new-onset SUD during the follow-up period.

CONCLUSIONS AND RELEVANCE

As compared with those who do not remit from an SUD, remitters have less than half the risk of developing a new SUD. Contrary to clinical lore, achieving remission does not typically lead to drug substitution but rather is associated with a lower risk of new SUD onsets.

Marijuana as a predictor of concurrent substance use among motor vehicle operators

Despite the adverse effects associated with marijuana abuse and dependence, marijuana is becoming more common-place in activities such as driving. Previous literature has discussed the high rates of cocaine, opioid and benzodiazepine use among users of marijuana, but no research has addressed the rates of concurrent use among drivers meeting abuse or dependence criteria. Each of these substances may produce effects detrimental to driving safety which may be compounded by concurrent substance use. This research examines rates of marijuana use, abuse, and dependence among an active sample of drivers (N = 7,734) in the 2007 National Roadside Survey. Mean age of participants was 36.89 years, and the majority were male (60.1%) and identified as White (59.2%). Participants who used marijuana but did not meet diagnostic criteria for abuse (n = 165) or dependence (n = 112) were significantly more likely to test positive for all substances than were those who did not use marijuana. Further, those that met criteria for marijuana abuse or dependence were more likely than those who did not meet criteria to test positive for THC, cocaine, and benzodiazepines and THC, cocaine, and opioids, respectively. The current research has implications for policy development and drugged driving interventions.

Marijuana use is associated with risky sexual behaviors in treatment-seeking polysubstance abusers

BACKGROUND

Multiple types of substance use are associated with HIV risk behaviors, but relatively little research has examined the association between marijuana use and risky sexual activities in treatment-seeking polysubstance abusing patients.

OBJECTIVES

This study evaluated the relationship between marijuana use and sexual behaviors in 239 patients with cocaine, opioid or alcohol use disorders who were initiating outpatient substance use treatment.

METHODS

Participants completed the HIV Risk Behavior Scale and were classified into one of three groups based on their marijuana use histories: never (n = 66), past but not current use (n = 124) or current use (n = 49).

RESULTS

Compared to never marijuana users, current and former marijuana users had a greater likelihood of having more than 50 lifetime sexual partners (odds ratio [OR] and 95% confidence interval [CI] = 3.9 [1.0-15.7] and 5.2 [1.6-17.3], respectively). Former marijuana users had increased risk of low frequency condom use with casual partners relative to never users (OR [95% CI] = 2.9 [1.1-7.6]). Moreover, current marijuana users were more likely than never users to have had more than two recent sexual partners (OR [95% CI] = 8.1 [1.94-33.44]).

CONCLUSION

Treatment-seeking polysubstance abusers with current or past marijuana use histories may be at greater risk of HIV infection than their counterparts who do not use marijuana. These data underscore the importance of increasing awareness about the potential association between marijuana use and increased high-risk sexual behavior among polysubstance abusing patients.

The influence of baseline marijuana use on treatment of cocaine dependence: application of an informative-priors bayesian approach

BACKGROUND

Marijuana use is prevalent among patients with cocaine dependence and often non-exclusionary in clinical trials of potential cocaine medications. The dual-focus of this study was to (1) examine the moderating effect of baseline marijuana use on response to treatment with levodopa/carbidopa for cocaine dependence; and (2) apply an informative-priors, Bayesian approach for estimating the probability of a subgroup-by-treatment interaction effect.

METHOD

A secondary data analysis of two previously published, double-blind, randomized controlled trials provided complete data for the historical (Study 1: N = 64 placebo), and current (Study 2: N = 113) data sets. Negative binomial regression evaluated Treatment Effectiveness Scores (TES) as a function of medication condition (levodopa/carbidopa, placebo), baseline marijuana use (days in past 30), and their interaction.

RESULTS

Bayesian analysis indicated that there was a 96% chance that baseline marijuana use predicts differential response to treatment with levodopa/carbidopa. Simple effects indicated that among participants receiving levodopa/carbidopa the probability that baseline marijuana confers harm in terms of reducing TES was 0.981; whereas the probability that marijuana confers harm within the placebo condition was 0.163. For every additional day of marijuana use reported at baseline, participants in the levodopa/carbidopa condition demonstrated a 5.4% decrease in TES; while participants in the placebo condition demonstrated a 4.9% increase in TES.

CONCLUSION

The potential moderating effect of marijuana on cocaine treatment response should be considered in future trial designs. Applying Bayesian subgroup analysis proved informative in characterizing this patient-treatment interaction effect.

Contingency management is efficacious and improves outcomes in cocaine patients with pretreatment marijuana use

BACKGROUND

Marijuana use is common in patients seeking treatment for cocaine use. Nevertheless, few studies have examined effects of marijuana use on treatment outcomes in general, and even fewer with respect to contingency management (CM) treatment, which has been criticized for potentially increasing non-reinforced drug use.

METHODS

Data from three randomized clinical trials of CM versus standard treatment (ST) in cocaine-abusing patients were examined (Petry et al., 2004, 2005a, 2006a; N=393) to assess effects of pretreatment marijuana use on outcomes. Patients were divided into two groups: (1) no self-reported marijuana use (No Pre-M; n=315) and (2) any self-reported marijuana use (Pre-M; n=78) in the 30 days pretreatment.

RESULTS

CM was especially efficacious in enhancing retention in Pre-M patients such that retention nearly doubled among Pre-M patients assigned to CM versus those assigned to ST. In contrast, CM exerted only modest benefits on retention in No Pre-M patients. Pretreatment marijuana use was not related to during-treatment abstinence from cocaine, opioids, and alcohol, or abstinence at a Month 9 follow-up. However, CM treatment and longest duration of abstinence achieved during treatment were significant predictors of Month 9 abstinence. Pre-M patients also evidenced more improvements in drug problems over time when randomized to CM.

CONCLUSIONS

CM was especially efficacious in facilitating retention and improving severity of drug-related problems in those who used marijuana in the month before initiating treatment.

Attention-deficit/hyperactivity disorder subtypes in adolescents with comorbid substance-use disorder

BACKGROUND

Little is known about the relationship between attention-deficit/hyperactivity disorder (ADHD) subtypes and substance-use disorder (SUD). As there is literature suggesting different subtype phenotypes, there may be subtype differences in regard to the risk for developing SUD and substance treatment response.

OBJECTIVES

To characterize the sample in a Clinical Trials Network (CTN) study according to ADHD subtypes and baseline psychosocial and substance-use characteristics and to compare subtypes on response to treatment.

METHODS

Secondary analyses on data collected from adolescents (n = 276) diagnosed with ADHD and SUD (non-nicotine) and treated with stimulant medication or placebo and cognitive behavioral therapy (CBT) for substance use. Participants were characterized as inattentive or combined ADHD subtype and compared on baseline characteristics and treatment outcome.

RESULTS

The combined subtype presented with more severe SUDs and higher rates of conduct disorder. There were a greater proportion of boys with inattentive subtype. The inattentive subtype appeared less ready for treatment (greater University of Rhode Island Change Assessment precontemplation scores) with poorer coping skills (poorer problem-solving and abstinence focused coping) at baseline. However, the two subtypes responded equally to treatment even after controlling for baseline differences.

CONCLUSIONS

Findings from this large community sample indicate that there were no subtype differences in treatment response, although there were differences in terms of substance use, antisocial behavior, readiness for treatment, and gender prior to treatment.

SCIENTIFIC SIGNIFICANCE

This study is the first to report on subtype differences for treatment response for non-nicotine SUD in a comorbid ADHD-SUD population. Despite some baseline differences, both subtypes responded equally to treatment, suggesting limited relevance for subtype designation on treatment planning.