Causal pathways between impulsiveness, cocaine use consequences, and depression

Mediational pathways among drug use initiation, use-related consequences, and quit attempts

Background

Factors that predict attempts to discontinue drug use are clinically relevant and may inform treatment. This study investigated drug use-related consequences as a predictor of drug quit attempts and treatment seeking among two cohorts of persons who use drugs.

Methods

Drug use and clinical characteristics were assessed among persons who use cocaine (N=176; urine-verified; 'Cocaine Cohort') and among those who use heroin (N=166; urine-verified; 'Heroin Cohort'). Mediation analyses assessed relationships among age at initial drug use, adverse drug-specific use-related consequences, and drug-specific quit attempts, separately for each cohort. Forward conditional logistic regression models evaluated drug use and clinical symptom scores as predictors of drug-specific treatment seeking.

Results

Controlling for age, mediation models showed that drug use consequences fully mediated the relationship between age at initial drug use and number of drug-specific quit attempts for the 'Cocaine Cohort' and 'Heroin Cohort' (R2=0.30, p<.001; R2=0.17, p<.001; respectively). Reporting more consequences predicted more quit attempts in each cohort, accounting for duration of use (ps<.001). Reporting more consequences also predicted greater likelihood of seeking drug use treatment (ps<.001) and was associated with more severe clinical symptoms in each cohort (ps<.05).

Conclusions

Using a parallel analysis design, we showed that reporting more drug-specific use-related consequences predicted more drug-specific quit attempts and greater likelihood to seek treatment in two cohorts: persons who use cocaine and those who use heroin. Our findings suggest that experiencing more drug use consequences predicts more attempts to seek drug abstinence and that assessment of consequences may be informative for treatment.

Characteristics and circumstances of cocaine-related completed suicide in Australia, 2000-2021

BACKGROUND

There has been a substantial global increase in cocaine use and associated harms. The current study aimed to: 1. Determine the case characteristics and circumstances of death of cocaine-related suicide in Australia 2000-2021; and 2. Determine the toxicological profiles of cases.

METHODS

Retrospective study of cocaine-related death in Australia, 2000-2021, retrieved from the National Coronial Information System (NCIS). Suicide intent was based upon the NCIS code for "Intentional Self-harm", derived from case circumstances and coroners' conclusions. Sex comparisons were made for all major variables.

RESULTS

A total of 157 cases were identified, 82.2% male, 79.5% employed, with a mean age of 32.3 years. Concerns for mental health were documented in 65.6%, a previous suicide attempt in 21.0%, a history of substance use treatment and/or negative consequences of substance use in 45.9% and injecting drug use in 14.6%. Manner of death amongst both sexes was predominantly by physical means (82.8%). Written intent was documented in 29.3%. Intense agitation prior to the incident was noted in 28.0% and conflict in 24.8%. The median blood cocaine concentration was 0.060 mg/L (range 0.007-5.500). Other drugs were present in 95.5%, most commonly alcohol (63.1%) with a median concentration of 0.140 g/100 ml. Psychostimulants other than cocaine were present in 31.2%.

CONCLUSIONS

The 'typical' cocaine-related suicide case was a male, aged in their early thirties, who was highly likely to be employed. The majority of cases used physical means, and a substantial minority were highly agitated and engaged in conflict prior to the fatal incident.

Rates, characteristics and toxicology of cocaine-related deaths in Australia, 2000-2021

AIMS

To (i) assess the population mortality rates of cocaine-related deaths in Australia, 2000 to 2021; (ii) determine the circumstances of death and case characteristics; and (iii) determine their toxicological profile.

DESIGN

Retrospective study of cocaine-related deaths in Australia, 2000 to 2021, retrieved from the National Coronial Information System.

SETTING

Australia-wide.

CASES

A total of 884 cases, mean age = 33.8 (SD, 10.0) years and 86.5% (n = 765) male.

MEASUREMENTS

Information was collected on characteristics, manner of death and toxicology. Only cases in which the presence of blood cocaine and/or metabolites were included.

FINDINGS

Population rates did not significantly increase during 2001-2011 (annual percentage change [APC] = 1.5; CI, -3.2, 6.5), but from 2012, there was a marked acceleration (APC = 20.0, 95% CI, 15.5, 25.3). Circumstances of death were unintentional drug toxicity (70.7%, n = 625), intentional self-harm (17.8%, n = 157), traumatic accident (11.5%, n = 102). The proportion of cases constituted by unintentional toxicity declined across the study period (APC = -2.6; CI, -3.1, -2.1). There was a substantial decline in the proportion of cases with a history of injecting drug use (APC = -5.7; CI, -6.5, -4.9) and with a history of substance use problems (APC = -3.2; CI, -3.9, -2.5). Both cocaine (0.100 vs 0.050 mg/L, P < 0.001) and benzoylecgonine (0.590 vs 0.240 mg/L, P < 0.001) concentrations were higher amongst toxicity cases than in cases of death from traumatic injury. Cocaethylene was present in 26.4% (n = 233), levamisole in 18.6% (n = 164) and lignocaine in 11.5% (n = 102). Psychoactive drugs in addition to cocaine were present in 92.9% (n = 821), most commonly opioids (50.5%, n = 446), alcohol (47.1%, n = 416), hypnosedatives (43.2%, n = 382) and psychostimulants (30.3%, n = 268). There was a steady decline in the proportion of opioid positive cases (APC = -5.4; CI, -6.3, -4.5).

CONCLUSIONS

There was a large increase in cocaine-related deaths across Australia from 2000 to 2021. This was accompanied by changes in case profiles, with histories of injecting drug use and substance use problems, as well as recent opioid use, becoming less prominent.

A randomised, double-blind, sham-controlled study of left prefrontal cortex 15 Hz repetitive transcranial magnetic stimulation in cocaine consumption and craving

Background

Cocaine use disorder (CUD) is a global health issue with no effective treatment. Repetitive Transcranial Magnetic Stimulation (rTMS) is a recently proposed therapy for CUD.

Methods

We conducted a single-center, randomised, sham-controlled, blinded, parallel-group research with patients randomly allocated to rTMS (15 Hz) or Sham group (1:1) using a computerised block randomisation process. We enrolled 62 of 81 CUD patients in two years. Patients were followed for eight weeks after receiving 15 15 Hz rTMS/sham sessions over the left dorsolateral prefrontal cortex (DLPFC) during the first three weeks of the study. We targeted the DLFPC following the 5 cm method. Cocaine lapses in twice a week urine tests were the primary outcome. The secondary outcomes were craving severity, cocaine use pattern, and psychometric assessments.

Findings

We randomly allocated patients to either an active rTMS group (32 subjects) or a sham treatment group (30 subjects). Thirteen (42%) and twelve (43.3%) of the subjects in rTMS and sham groups, respectively, completed the full trial regimen, displaying a high dropout rate. Ten/30 (33%) of rTMS-treated patients tested negative for cocaine in urine, in contrast to 4/27 of placebo controls (p = 0.18, odd ratio 2.88, CI 0.9–10). The Kaplan-Meier survival curve did not state a significant change between the treated and sham groups in the time of cocaine urine negativisation (p = 0.20). However, the severity of cocaine-related cues mediated craving (VAS peak) was substantially decreased in the rTMS treated group (p<0.03) after treatment at T1, corresponding to the end of rTMS treatment. Furthermore, in the rTMS and sham groups, self-reported days of cocaine use decreased significantly (p<0.03). Finally, psychometric impulsivity parameters improved in rTMS-treated patients, while depression scales improved in both groups.

Conclusions

In CUD, rTMS could be a useful tool for lowering cocaine craving and consumption.

Trial registration

The study number on clinicalTrials.gov is NCT03607591.

Impulsivity in cocaine users compared to matched controls: Effects of sex and preferred route of cocaine use

BACKGROUND

Impulsivity has been identified as playing a role in cocaine use. The purpose of this study was to explore self-report measures of impulsivity in large groups of male and female cocaine users and matched controls and to determine if differences in impulsivity measures within a group of cocaine users related to self-reported money spent on cocaine and route of cocaine use.

METHODS

Eight self-report impulsivity measures yielding 34 subscales were obtained in 230 cocaine users (180 M, 50 F) and a matched group of 119 healthy controls (89 M, 30 F). Correlational analysis of the questionnaires revealed 2 factors: Impulsive Action (Factor 1) consisting of many traditional impulsivity measures and Thrill-seeking (Factor 2) consisting of delay discounting, sensation and thrill seeking.

RESULTS

Sex influenced within group comparisons. Impulsive Action scores did not vary as a function of sex within either group. But, male controls and male cocaine users had greater Thrill-seeking scores than females within the same group. Sex also influenced between group comparisons. Male cocaine users had greater Impulsive Action scores while female cocaine users had greater Thrill-seeking scores than their sex-matched controls. Among cocaine users, individuals who preferred insufflating ("snorting") cocaine had greater Thrill-seeking scores and lower Impulsive Action scores than individuals who preferred smoking cocaine. Individuals who insufflate cocaine also spent less money on cocaine.

CONCLUSIONS

Greater Impulsive Action scores in males and Thrill-seeking scores in females were associated with cocaine use relative to controls.

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.

Demographic, Cannabis Use, and Depressive Correlates of Cannabis Use Consequences in Regular Cannabis Users

BACKGROUND AND OBJECTIVES

Regular cannabis users experience cannabis-related consequences across many domains of functioning. The present study examined demographic, cannabis use, and depressive correlates of cannabis consequences. We hypothesized that (1) earlier onset of use would predict greater psychological and functional consequences; and (2) women would endorse more psychological and withdrawal consequences.

METHODS

Data were collected from an urban sample of 184 adults who reported regular cannabis use. Seventeen items from a cannabis consequence checklist were grouped into three domains: Psychological Consequences, Cannabis Withdrawal, and Functional Consequences. Three multiple regressions were performed to explore demographic and cannabis use correlates of each domain. Correlations between domains and depressive symptoms were assessed using Pearson's r.

RESULTS

Greater endorsement on the Psychological Consequence subgroup was predicted by female sex, lower educational attainment, and treatment-seeking history for cannabis abuse/dependence. Individuals with greater number of quit attempts or treatment-seeking history endorsed more items in the Cannabis Withdrawal domain. Although the model failed to reach significance for Functional Consequences, age at onset of regular and daily cannabis use were negatively associated with this domain. Correlational analyses demonstrated higher Beck Depression Inventory-Second Edition scores were related to greater endorsement of Psychological Consequence and Cannabis Withdrawal items.

DISCUSSION AND CONCLUSIONS

Regular cannabis users report consequences of use, which can be grouped into content-specific subgroups. Individual characteristics are differentially associated with these subgroups.

SCIENTIFIC SIGNIFICANCE

Understanding which individual characteristics are related to cannabis use sequelae could help identify those at risk for greater consequences, thus leading to improved assessment and treatment interventions. (Am J Addict 2019;28:295-302).

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.