Longitudinal Outcomes Among a Cohort of Crack Users After 12 Years from Treatment Discharge

Health outcomes associated with crack-cocaine use: Systematic review and meta-analyses

BACKGROUND

Crack-cocaine use is prevalent largely in socio-economically marginalized populations in the Americas. Its use has been associated with diverse health outcomes, yet no recent or systematic reviews of these exist.

METHODS

A systematic review of health outcomes associated with crack-cocaine use was performed, using MEDLINE, Scopus, Web of Science, CINAHL, PsycINFO, and LILACS up to October 2016. Search terms included crack-cocaine and health outcome-related keywords, targeting peer-reviewed studies on quantified health outcomes associated with crack-cocaine use. Random effects meta-analyses produced pooled odds ratios. Levels of evidence for major results were assessed using the GRADE approach. A review protocol was registered with PROSPERO (CRD42016035486).

RESULTS

Of 4700 articles returned, 302 met eligibility criteria, reporting on health outcomes for 14 of 22 ICD-10 chapters. Conclusive evidence and meta-analyses showed positive associations between crack-cocaine use and blood/sexually transmitted diseases (HIV and hepatitis C virus, others); moderate evidence and meta-analyses supported associations with neonatal health, and violence. There were mixed associations for mental and other health outcomes, yet insufficient evidence to perform meta-analyses for many categories (e.g., mortality). Most underlying research was of limited or poor quality, with crack-cocaine commonly assessed as a secondary covariate.

CONCLUSIONS

Crack-cocaine use was associated with a range of health outcomes, although it was unclear if there was direct causal impact, interactions between risk factors, or external drivers of both crack-cocaine use and outcomes. Rigorous epidemiological studies are needed to systematically assess health outcomes of crack-cocaine use and underlying pathways, also to inform evidence-based interventions.

Behavioural, biochemical and molecular changes induced by chronic crack-cocaine inhalation in mice: The role of dopaminergic and endocannabinoid systems in the prefrontal cortex

Crack-cocaine addiction has increasingly become a public health problem worldwide, especially in developing countries. However, no studies have focused on neurobiological mechanisms underlying the severe addiction produced by this drug, which seems to differ from powder cocaine in many aspects. This study investigated behavioural, biochemical and molecular changes in mice inhaling crack-cocaine, focusing on dopaminergic and endocannabinoid systems in the prefrontal cortex. Mice were submitted to two inhalation sessions of crack-cocaine a day (crack-cocaine group) during 11 days, meanwhile the control group had no access to the drug. We found that the crack-cocaine group exhibited hyperlocomotion and a peculiar jumping behaviour ("escape jumping"). Blood collected right after the last inhalation session revealed that the anhydroecgonine methyl ester (AEME), a specific metabolite of cocaine pyrolysis, was much more concentrated than cocaine itself in the crack-cocaine group. Most genes related to the endocannabinoid system, CB1 receptor and cannabinoid degradation enzymes were downregulated after 11-day crack-cocaine exposition. These changes may have decreased dopamine and its metabolites levels, which in turn may be related with the extreme upregulation of dopamine receptors and tyrosine hydroxylase observed in the prefrontal cortex of these animals. Our data suggest that after 11 days of crack-cocaine exposure, neuroadaptive changes towards downregulation of reinforcing mechanisms may have taken place as a result of neurochemical changes observed on dopaminergic and endocannabinoid systems. Successive changes like these have never been described in cocaine hydrochloride models before, probably because AEME is only produced by cocaine pyrolysis and this metabolite may underlie the more aggressive pattern of addiction induced by crack-cocaine.

Oxidative stress and BDNF as possible markers for the severity of crack cocaine use in early withdrawal

RATIONALE

An important goal of addiction research is to discover neurobiological markers that could predict the severity of addiction and help to determine appropriate treatment. Brain-derived neurotrophic factor (BDNF) and thiobarbituric acid reactive substances (TBARS) are being related to cerebral plasticity and impairment caused by substance abuse.

OBJECTIVES

This study aims to evaluate alteration of TBARS and BDNF levels among crack cocaine users during early drug withdrawal and its relationship to severity of drug use.

METHODS

Forty-nine adults crack cocaine users were recruited at a public psychiatric hospital with a specialized addiction treatment unit. Blood sample was collected at intake and discharge for the analysis of TBARS and BDNF measures. Information about drug use was assessed by the Addiction Severity Index 6th Version (ASI-6). Detailed information about crack cocaine use was obtained through the "Profile of the crack cocaine user." Severity of crack use was estimated using information from age of first crack use, years of crack use, and crack rocks used in the previous 30 days.

RESULTS

There is a positive correlation between TBARS levels and severity of crack cocaine use (R = 0.304, p = 0.04) and a negative correlation between BDNF and severity of crack cocaine use (R = -0.359, p = 0.01) at discharge. Also, we found an inverse correlation between TBARS and BDNF levels (R = -0.294, p = 0.004) at discharge.

CONCLUSIONS

Our findings suggest that BDNF and TBARS could be possible markers for the severity of drug use. Further studies may show how those markers could be related to staging, prognosis, and treatment in crack cocaine dependence.

Increase in brain-derived neurotrophic factor expression in early crack cocaine withdrawal

Recent reports suggest that brain-derived neurotrophic factor (BDNF) could be a biomarker for relapse, drug craving and withdrawal severity. In particular, elevated BDNF levels among former cocaine users have been associated with higher rates of relapse in 90 d. However, no data are available on BDNF levels at baseline and during crack cocaine withdrawal. This study evaluated BDNF among crack cocaine users during inpatient treatment, before and after withdrawal, vs. healthy controls. Clinical correlates with changes in BDNF levels were also assessed. Serum BDNF was evaluated in 49 male crack users on the first and last days of hospitalization and in 97 healthy controls. Serum BDNF was assayed using a sandwich ELISA kit. BDNF levels were significantly lower upon admission when compared to controls, even after adjustment for age, length of inpatient treatment, number of crack rocks used in the last 30 d, years of crack use and interaction between the latter two variables. At discharge, BDNF levels between patients and controls were similar. Number of crack rocks used in the last 30 d and years of crack use were inversely correlated with the outcome. Our findings show that BDNF levels increase during early crack cocaine withdrawal, at an inverse correlation with number of crack rocks used in the last 30 d and years of crack use.

Patterns, determinants and barriers of health and social service utilization among young urban crack users in Brazil

Background

Crack use is prevalent across the Americas, and specifically among marginalized urban street drug users in Brazil. Crack users commonly feature multiple physical and mental health problems, while low rates of and distinct barriers to help service use have been observed in these populations. This study examined profiles and determinants of social and health service utilization, and unmet service needs, in a two-city sample of young (18–24 years), marginalized crack users in Brazil.

Methods

N = 160 study participants were recruited by community-based methods from impoverished neighborhoods in the cities of Rio de Janeiro (n = 81) and Salvador (n = 79). A mixed methods protocol was used. Participants’ drug use, health, and social and health service utilization characteristics were assessed by an anonymous interviewer-administered questionnaire completed in a community setting; descriptive statistics on variables of interest were computed. Service needs and barriers were further assessed by way of several focus groups with the study population; narrative data were qualitatively analyzed. The study protocol was approved by institutional ethics review boards; data were collected between November 2010 and June 2011.

Results

The majority of the sample was male, without stable housing, and used other drugs (e.g., alcohol, marijuana). About half the sample reported physical and mental health problems, yet most had not received medical attention for these problems. Only small minorities had utilized locally available social or health services; utilization appeared to be influenced by sex, race and housing characteristics in both sites. Participants cited limited service resources, lack of needs-specific professional skills, bureaucratic barriers and stigma as obstacles to better service access. However, most respondents stated strong interest and need for general social, health and treatment services designed for the study population, for which various key features were emphasized as important.

Conclusions

The study contributes substantive evidence to current discussions about the development and utilization of health and treatment interventions for crack use in Brazil. Based on our data, crack users’ social, service needs are largely unmet; these gaps appear to partly root in systemic barriers of access to existing services, while improved targeted service offers for the target population seem to be needed also.