Association of substance use disorders with childhood trauma but not African genetic heritage in an African American cohort

Examining the Effects of Adverse Childhood Experiences and Gender on Trauma-Informed Intervention Outcomes

Purpose

The prevalence of Adverse Childhood Experiences (ACEs) and their link to negative behavioral and health outcomes is well documented, but very few studies have empirically examined the effect of ACEs on intervention outcomes. There is also emerging evidence of gender differences in vulnerability to developing traumatic symptoms, which relates to intervention outcomes. The current study examined the effects of ACEs and gender on trauma-informed intervention outcomes in a community-based clinical setting.

Methods

The study includes data from children who were treated with trauma-informed intervention services grounded in the Attachment, Self-Regulation, and Competency (ARC) framework from 2017 to 2019. ACE scores are measured as a total across 10 items and different types, maltreatment versus family dysfunction, at intake. Children's trauma-related symptoms are assessed at intake and every 90 days under the ARC framework. In order to examine the changes of traumatic symptoms over time, a total of 362 children with three time points are included for the current analyses using Multilevel modeling with SAS PROC MIXED.

Results

The study found that a trauma-informed intervention based on the ARC framework was effective in reducing children's trauma related symptoms until they experienced 6 or more ACEs. The intervention effect, however, did not hold when children's ACEs were cumulated to 7 or more. The study also revealed gender differences in intervention outcomes.

Conclusions

The finding has significant implications for early detection and preventative intervention efforts with children's ACEs before their ACEs further cumulate to a higher number. Gender difference should be considered in intervention planning and monitored during the intervention process.

Family, Individual, and Other Risk Factors Contributing to Risk of Substance Abuse in Young Adults: A Narrative Review

Substance use disorder and the availability of certain over-the-counter drugs are worldwide issues that affect many individuals, both mentally and physically. As a result, the frequent use of this substance can lead to substance abuse. This phenomenon is also becoming more prevalent with time, and it does not differentiate between genders, ages, races, or religions. This review aimed to provide an overview of studies related to substance abuse, the individuals who tend to abuse these substances, and their risk factors. We also aimed to discuss, identify, and analyze the factors that increase the risk of substance abuse among young adults. We performed a thorough search for related studies using PubMed to provide a comprehensive review of the risk factors and side effects experienced by young adults. The selected indexing terms included "substance abuse,""risk factors," and "personality traits," among others. Information was gathered from relevant peer-reviewed publications, and thereafter refined, and summarized.

Trauma-Informed Intervention with Children: Integrating the CANS Assessment with the ARC Framework in a Clinical Setting

Ongoing trauma-focused assessment is critical to developing trauma-informed treatment plans. The current study examines the clinical benefits of utilizing the Child and Adolescent Needs and Strengths (CANS) assessment to guide intervention based on the Attachment, Self-Regulation, and Competency (ARC) model to address children's trauma related symptoms in a rural state. WV CANS was developed by adapting the language of original CANS to be culturally specific to the state's unique situation and culture in consultation with the original CANS developer. This study included the data from children who received mental health services under WV CANS-ARC mapping from 2017 to 2019. Children's trauma-related symptoms are assessed using the WV CANS at intake and every 90 days to identify any changes in their symptoms. In order to examine the changes of traumatic symptoms over time, the study was limited to children who have at least three time points, with a total of 362 children used for the current analyses using Multilevel modeling with SAS PROC MIXED. The study found that children's trauma related symptoms significantly decreased in all ARC outcome domains over time after adjusting for basic demographic variables. The current study contributes to the evidence on treatment for children's trauma-related symptoms, especially with the application of the CANS-ARC mapping in a real-world clinical setting. The findings have significant implications for clinicians in integrating the assessment and treatment process using CANS-ARC mapping and for cross-system collaboration with continuity of care serving children who have experienced trauma.

Analyses of polymorphisms of intron 2 of OPRK1 (kappa-opioid receptor gene) in association with opioid and cocaine dependence diagnoses in an African-American population

RATIONALE

The dynorphin/kappa-opioid receptor (KOR) system (encoded by PDYN and OPRK1 genes respectively) is highly regulated by repeated exposure to drugs of abuse, including mu-opioid agonists and cocaine. These changes in the dynorphin/KOR system can then influence the rewarding effects of these drugs of abuse. Activation of the dynorphin/KOR system is also thought to have a role in the pro-addictive effects of stress. Recent in vitro assays showed that the OPRK1 intron 2 may function as a genomic enhancer in the regulation KOR expression, and contains a glucocorticiod-responsive sequence site. We hypothesize that SNPs in intron 2 of OPRK1 are associated with categorical opioid or cocaine dependence diagnoses, as well as with dimensional aspects of drug use (i.e., magnitude of drug exposure).

METHODS

This study includes 577 subjects ≥ 18 years old, with African ancestry (AA) from the USA. They were divided into three groups: 152 control subjects, 142 persons with lifetime opioid dependence diagnosis (OD), and 283 subjects with lifetime cocaine dependence diagnosis (CD). Five SNPs (rs16918909, rs7016778, rs997917, rs6473797, rs10111937) that span 10 Kb nucleotides in intron 2 of OPRK1 were used for the association analyses. Genotyping was performed with the Smokescreen® array or sequencing of PCR-amplified DNA fragments. Association analyses for OD and CD diagnoses and the OPRK1 intron 2 alleles were carried out with Fisher's exact test. The Kreek-McHugh-Schluger-Kellogg (KMSK) scales were used for dimensional measure of maximum exposure to specific drugs, using Mann-Whitney tests.

RESULTS

Two SNPs, rs997917 and rs10111937 showed point-wise significant allelic association (p < 0.05) with CD diagnosis, and rs10111937 showed a point-wise significance in association with OD. None of these single SNP associations with categorical diagnoses were significant after correction for multiple testing (p_corr > 0.05). However, significant associations of several genotype patterns (diplotypes) were found with cocaine dependence, but none for opioid dependence. The most significant genotype pattern with cocaine dependence diagnosis occurred for rs6473797 and rs10111937 (p_corr = 0.036, odds ratio = 1.92, FDR < 0.05), and survived correction for multiple testing. Dimensional analyses with KMSK scores show that persons with either rs997917 or rs10111937 variants had greater exposure to cocaine, compared to those with prototype allele (Mann-Whitney tests, point-wise).

CONCLUSIONS

This study provides additional support of potential importance of regulatory regions of intron 2 of the OPRK1 gene in development of cocaine and opioid dependence diagnoses, in a population with African-American ancestry.

Neurobiological mechanisms of early life adversity, blunted stress reactivity and risk for addiction

Blunted stress reactivity resulting from early exposure to stress during childhood and adolescence may increase vulnerability to addiction. Early life adversity (ELA) affects brain structure and function and results in blunted stress axis reactivity. In this review, we focus on the underlying neurobiological mechanisms associated with a blunted response to stress, ELA, and risk for addictive disorders. ELA and blunted reactivity are accompanied by unstable mood regulation, impulsive behaviors, and reduced cognitive function. Neuroimaging studies reveal cortical and subcortical changes in persons exposed to ELA and those who have a genetic disposition for addiction. We propose a model in which blunted stress reactivity may be a marker of risk for addiction through an altered motivational and behavioral reactivity to stress that contribute to disinhibited behavioral reactivity and impulsivity leading in turn to increased vulnerability for substance use. Evidence supporting this hypothesis in the context of substance use initiation, maintenance, and risk for relapse is presented. The effects of ELA on persons at risk for addiction may lead to early experimentation with drugs of abuse. Early adoption of drug intake may alter neuroregulation in such vulnerable persons leading to a permanent dysregulation of motivational responses consistent with dependence. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Maternal separation increases cocaine intake through a mechanism involving plasticity in glutamate signalling

Early-life stress (ELS) is associated with negative consequences, including maladaptive long-lasting brain effects. These alterations seem to increase the likelihood of developing substance use disorders. However, the molecular consequences of ELS are poorly understood. In the present study, we tested the impact of ELS induced by maternal separation with early weaning (MSEW) in CD1 male mice at different phases of cocaine self-administration (SA). We also investigated the subsequent alterations on GluR2, GluR1, cAMP response element-binding (CREB), and CREB-phosphorylation (pCREB) in ventral tegmental area (VTA) and nucleus accumbens (NAc) induced by both MSEW and cocaine SA. Our results show that MSEW animals expressed a higher cocaine intake, an increased vulnerability to the acquisition of cocaine SA, and incapacity to extinguish cocaine SA behaviour. MSEW mice showed decreased GluR2 and increased GluR1 and pCREB in NAc. Also, results displayed reduction of basal levels of GluR1 and CREB and an elevation of GluR1/GluR2 ratio in the VTA. Such results hint at an enhanced glutamatergic function in NAc and increased excitability of VTA DA neurons in maternally separated mice. Altogether, our results suggest that MSEW induces molecular alterations in the brain areas related to reward processing, increasing the vulnerability to depression and cocaine-seeking behaviour.

Association of Serotonin Transporter (SERT) Polymorphisms with Opioid Dependence and Dimensional Aspects of Cocaine Use in a Caucasian Cohort of Opioid Users

INTRODUCTION

A functional tandem repeat polymorphism in the promoter of the serotonin transporter (SERT) gene (SLC6A4) has been studied for association to neuropsychiatric conditions, including substance use disorders. Short (S) forms of this repeat result in reduced transcription, and presumably greater synaptic levels of serotonin, which are involved in opioid and cocaine-induced reward. Dual exposure to heroin and cocaine is a common pattern of poly-drug use and is associated with considerable morbidity. We hypothesize that SLC6A4 variants are associated with cocaine exposure in subjects with an opioid dependence diagnosis (OD), and also in non-dependent opioid users (NOD). Other single nucleotide polymorphisms (SNPs) of SLC6A4 may also be likewise associated.

MATERIALS AND METHODS

This study determined whether variants of the SLC6A4 promoter repeats and two intronic SNPs, rs16965628 and rs2066713, are associated with categorical diagnoses of opioid dependence (DSM-IV criteria) and with dimensional aspects of cocaine use, in a Caucasian cohort (n=591). Three groups of subjects were examined: (1) 276 subjects with opioid dependence diagnosis (OD); (2) 163 subjects who had used opioids for non-medical reasons but never had an opioid dependence diagnosis (NOD); (3) 152 healthy controls (HC).

RESULTS

Aside from high exposure to heroin in the OD group, relatively high exposure to cocaine was detected in both OD and NOD groups. The SERT repeat genotype (classified as "long-long" [LL] versus "short-long" plus "short-short" [SL+SS]) was not associated with categorical opioid dependence diagnoses. A nominally significant association was identified with the [SL+SS] genotype of SLC6A4 and cocaine KMSK scores ≥"cutpoint" for a cocaine dependence diagnosis (p=0.026). The [SL+SS] genotype was associated with more rapid cocaine escalation than the LL genotype. No significant associations of rs16965628 and rs2066713 SNPs were found overall.

CONCLUSION

The functional SERT promoter tandem repeat genotype may be associated to heavy cocaine exposure and more rapid escalation of cocaine use, in persons with and without opioid dependence diagnosis.

LRRK2 Gene Variants Associated With a Higher Risk for Alcohol Dependence in Multiethnic Populations

Background: Genetics influence the vulnerability to alcohol use disorders, and among the implicated genes, three previous studies have provided evidences for the involvement of LRRK2 in alcohol dependence (AD). LRRK2 expression is broadly dysregulated in postmortem brain from AD humans, as well as in the brain of mice with alcohol dependent-like behaviors and in a zebrafish model of alcohol preference. The aim of the present study was to evaluate the association of variants in the LRRK2 gene with AD in multiethnic populations from South and North America. Methods: Alcohol-screening questionnaires [such as CAGE and Alcohol Use Disorders Identification Test (AUDIT)] were used to determine individual risk of AD. Multivariate logistic regression analyses were done in three independent populations (898 individuals from Bambuí, Brazil; 3,015 individuals from Pelotas, Brazil; and 1,316 from the United States). Linkage disequilibrium and conditional analyses, as well as in silico functional analyses, were also conducted. Results: Four LRRK2 variants were significantly associated with AD in our discovery cohort (Bambuí): rs4768231, rs4767971, rs7307310, and rs1465527. Two of these variants (rs4768231 and rs4767971) were replicated in both Pelotas and US cohorts. The consistent association signal (at the LRRK2 locus) found in populations with different genetic backgrounds reinforces the relevance of our findings. Conclusion: Taken together, these results support the notion that genetic variants in the LRRK2 locus are risk factors for AD in humans.

Further evidence for the association of GAL, GALR1 and NPY1R variants with opioid dependence

Aim: Heroin addiction is a chronic, relapsing disease that has genetic and environmental, including drug-induced, contributions. Stress influences the development of addictions. This study was conducted to determine if variants in stress-related genes are associated with opioid dependence (OD). Patients & methods: One hundred and twenty variants in 26 genes were analyzed in 597 Dutch subjects. Patients included 281 OD in methadone maintenance with or without heroin-assisted treatment and 316 controls. Results: Twelve SNPs in seven genes showed a nominally significant association with OD. Experiment-wise significant associations (p < 0.05) were found for three SNP pairs, through an interaction effect: NPY1R/GAL rs4691910/rs1893679, NPY1R/GAL rs4691910/rs3136541 and GALR1/GAL rs9807208/rs3136541. Conclusion: This study lends more evidence to previous reports of association of stress-related variants with heroin dependence.

Interpersonal Violence Exposure and Chronic Pain in Adult Sickle Cell Patients

Almost half of sickle cell disease (SCD) patients develop chronic, debilitating physical pain with uncertain genesis for which they primarily receive opiate-based palliative treatment. Psychological trauma exposure, especially interpersonal victimization, has been linked to the perception of pain in several medical diseases, but has yet to be examined in SCD patients. This study examines self-reported chronicity of pain and use of prescribed opiates in 50 adult SCD patients with and without a history of interpersonal violence exposure. We conducted a retrospective chart review of 50 consecutive SCD patients seen for medical care in an adult subspecialty hematology clinic. Data collected included demographics, opiate use, pain chronicity, and measures of anxiety, depression, and interpersonal violence exposure. Sixty-eight percent of patients reported past interpersonal violence exposure. The mean number of types of interpersonal violence exposure, including physical, sexual, or emotional abuse, was 2.76 (SD = 1.63). SCD patients with a history of interpersonal violence exposure were almost five times more likely to report chronic pain and more than six times more likely to report use of opiate-based medications on a daily basis compared with SCD patients with no history of violence exposure. Depression and anxiety symptoms were associated with violence exposure, but did not account for the relationship between violence exposure and chronic pain or prescribed opiate use. Screening and assessment of exposure to interpersonal violence may be useful in addition to screening for mental health problems in the management of chronic pain with adults diagnosed with SCD. Such screening may contribute to addressing health care disparities given the preponderance of SCD patients who are of African American ethnoracial background.

A systematic scoping review of research on Black participants in the National Drug Abuse Treatment Clinical Trials Network

Black individuals experience a disproportionate burden of substance-related disabilities and premature death relative to other racial/ethnic groups, highlighting the need for additional research. The National Drug Abuse Treatment Clinical Trials Network (CTN), a research platform for multisite behavioral, pharmacological, and integrated trials designed to evaluate the effectiveness of substance use treatments in community settings with diversified patient populations, provides a wealth of research knowledge on substance use. Although CTN trials have enrolled over 5,000 Black individuals since its inception in 2000, there has been no synthesis of the findings, discussion of the implications, or suggestions for future research for Black individuals. Members of the Minority Interest Group of the CTN conducted a scoping review of published research on Black participants in CTN trials. Studies were included if the sample was more than 75% Black and/or specific findings pertaining to Black participants were reported. The review yielded 50 articles, with studies that mostly focused on baseline characteristics, followed by substance use treatment outcomes, HIV/risky sex behaviors, retention, comorbid conditions and measurement issues. This review highlighted the importance of several issues that are critical to understanding and treating substance misuse among Black people, such as the characteristics of Black people entering treatment, measurement equivalence, and engaging/retaining adolescents and young adults in treatment. There is still a continued need to identify the most effective treatments for Black individuals who use substances. The CTN offers several untapped opportunities to further advance research on Black individuals who use substances (e.g., secondary analyses of publicly available data). (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Management of opioid use disorder in the USA: present status and future directions

Opioid use disorder is characterised by the persistent use of opioids despite the adverse consequences of its use. The disorder is associated with a range of mental and general medical comorbid disorders, and with increased mortality. Although genetics are important in opioid use disorder, younger age, male sex, and lower educational attainment level and income, increase the risk of opioid use disorder, as do certain psychiatric disorders (eg, other substance use disorders and mood disorders). The medications for opioid use disorder, which include methadone, buprenorphine, and extended-release naltrexone, significantly improve opioid use disorder outcomes. However, the effectiveness of medications for opioid use disorder is limited by problems at all levels of the care cascade, including diagnosis, entry into treatment, and retention in treatment. There is an urgent need for expanding the use of medications for opioid use disorder, including training of health-care professionals in the treatment and prevention of opioid use disorder, and for development of alternative medications and new models of care to expand capabilities for personalised interventions.

VMAT2 gene (SLC18A2) variants associated with a greater risk for developing opioid dependence

Aim: To determine if selected serotonergic and noradrenergic gene variants are associated with heroin addiction. Subjects & methods: A total of 126 variants in 19 genes in subjects with Dutch European ancestry from The Netherlands. Subjects included 281 opioid-dependent volunteers in methadone maintenance or heroin-assisted treatment, 163 opioid-exposed but not opioid-dependent volunteers who have been using illicit opioids but never became opioid-dependent and 153 healthy controls. Results: Nominal associations were indicated for 20 variants in six genes including an experiment-wise significant association from the combined effect of three SLC18A2 SNPs (rs363332, rs363334 and rs363338) with heroin dependence (p_final = 0.047). Conclusion: Further studies are warranted to confirm and elucidate the role of these variants in the vulnerability to opioid addiction.

Association of variants of prodynorphin promoter 68-bp repeats in caucasians with opioid dependence diagnosis: Effect on age trajectory of heroin use

The dynorphin/kappa opioid receptor (Dyn/KOR) system is involved in reward processing and dysphoria/anhedonia. Exposure to mu-opioid receptor agonists such as heroin increases expression of the prodynorphin gene (PDYN) in the brain. In this study in a Caucasian cohort, we examined the association of the functional PDYN 68-bp repeat polymorphism with opioid use disorders. In this case-control study, 554 subjects with Caucasian ancestry (142 healthy controls, 153 opioid-exposed, but never opioid dependent, NOD, and 259 with an opioid dependence diagnosis, OD) were examined for association of the PDYN 68-bp repeats with the diagnosis of opioid dependence (DSM-IV criteria), with a dimensional measure of heroin exposure (KMSK scale), and age trajectory parameters of heroin use (age of heroin first use, and age of onset of heaviest use). The PDYN 68-bp repeat genotype (classified as: "short-short" [SS], "long-long" [LL], and "short-long" [SL], based on the number of repeats) was not associated with categorical opioid dependence diagnoses. However, the LL genotype was associated with later age of first heroin use than the SS + SL genotype (19 versus 18 years; p < 0.01). This was also confirmed by a significant positive correlation between the number of repeats and the age of first use of heroin, in volunteers with OD (Spearman r = 0.16; p = 0.01). This suggests that the functional PDYN 68-bp repeat genotype is associated with the age of first use of heroin in Caucasians diagnosed with opioid dependence.

Association of genetic ancestry with striatal dopamine D2/D3 receptor availability

Despite ethnic differences in allele frequencies of variants in dopaminergic genes associated with dopamine D2/D3 receptor availability (D2R), no study to date has investigated the relationship between genetic ancestry and striatal D2R. Here, we show that ancestry-informative markers significantly predict dorsal striatal D2R in 117 healthy ethnically diverse residents of the New York metropolitan area using Positron Emission Tomography (PET) with [¹¹C]raclopride (P<0.0001), while correcting for age, sex, BMI, education, smoking status, and estimated socioeconomic status (ZIP codes). Effects of ethnicity on D2R were not driven by variation in dopaminergic candidate genes. Instead, candidate gene associations with striatal D2R were diminished when correcting for ancestry. These findings imply that future studies investigating D2 receptor genes should covary for genetic ancestry or study homogeneous populations. Moreover, ancestry studies on human neurobiology should control for socioeconomic differences between ethnic groups.

A non-coding CRHR2 SNP rs255105, a cis-eQTL for a downstream lincRNA AC005154.6, is associated with heroin addiction

Dysregulation of the stress response is implicated in drug addiction; therefore, polymorphisms in stress-related genes may be involved in this disease. An analysis was performed to identify associations between variants in 11 stress-related genes, selected a priori, and heroin addiction. Two discovery samples of American subjects of European descent (EA, n = 601) and of African Americans (AA, n = 400) were analyzed separately. Ancestry was verified by principal component analysis. Final sets of 414 (EA) and 562 (AA) variants were analyzed after filtering of 846 high-quality variants. The main result was an association of a non-coding SNP rs255105 in the CRH (CRF) receptor 2 gene (CRHR2), in the discovery EA sample (Pnominal = .00006; OR = 2.1; 95% CI 1.4-3.1). The association signal remained significant after permutation-based multiple testing correction. The result was corroborated by an independent EA case sample (n = 364). Bioinformatics analysis revealed that SNP rs255105 is associated with the expression of a downstream long intergenic non-coding RNA (lincRNA) gene AC005154.6. AC005154.6 is highly expressed in the pituitary but its functions are unknown. LincRNAs have been previously associated with adaptive behavior, PTSD, and alcohol addiction. Further studies are warranted to corroborate the association results and to assess the potential relevance of this lincRNA to addiction and other stress-related disorders.

Genetic variations in genes of the stress response pathway are associated with prolonged abstinence from heroin

AIM

This study assesses whether genetic variants in stress-related genes are associated with prolonged abstinence from heroin in subjects that are not in long-term methadone treatment.

METHODS

Frequencies of 117 polymorphisms in 30 genes were compared between subjects with history of heroin addiction, either without agonist treatment (n = 129) or in methadone maintenance treatment (n = 923).

RESULTS

SNP rs1500 downstream of CRHBP and an interaction of SNPs rs10482672 (NR3C1) and rs4234955 (NPY1R/NPY5R) were significantly associated with prolonged abstinence without agonist treatment.

CONCLUSION

This study suggests that variability in stress-related genes may contribute to the ability of certain subjects to remain in prolonged abstinence from heroin, possibly due to higher resilience to stress.

Dopamine gene variants in opioid addiction: comparison of dependent patients, nondependent users and healthy controls

AIM

To determine whether specific dopaminergic system gene variants are associated with opioid dependence.

PATIENTS & METHODS

Subjects included 153 healthy controls, 163 opioid exposed, but not dependent and 281 opioid dependent. Genotypes of 90 variants in 13 genes were examined.

RESULTS

The most significant results were obtained for DA β-hydroxylase variants, rs2073837 and rs1611131, which were associated with protection from addiction (q = 0.0172, 0.0415, respectively) and the functional TH variant, rs2070762, was associated with more risk (q = 0.0387). The three variants also showed a combined effect that remained significant after correction for multiple testing (p_final = 0.0039).

CONCLUSION

These data offer support that dopaminergic gene variants have a role in opioid dependence and warrant further study.

The μ-opioid receptor nonsynonymous variant 118A>G is associated with prolonged abstinence from heroin without agonist treatment

AIM

This study assesses whether opioid-related gene variants contribute to reduced vulnerability to relapse to heroin in persons who are not treated with μ-opioid receptor agonist.

METHODS

Genotypes of 71 SNPs, in nine genes, were analyzed for association with long-term abstinence in former heroin-dependents of European/Middle Eastern ancestry, either without agonist treatment (n = 129) or in methadone maintenance treatment (n = 922).

RESULTS

The functional OPRM1 nonsynonymous SNP rs1799971 (118A>G) showed significant association with long-term abstinence (P_permutation  = 0.03, dominant model, OR: 2.2; 95% CI: 1.5-3.3).

CONCLUSION

Since the stress axis is regulated in part by β-endorphin, this functional OPRM1 SNP may blunt the endogenous stress response and contribute to reduced vulnerability for relapse.

Childhood Maltreatment and Development of Substance Use Disorders: A Review and a Model of Cognitive Pathways

Exposure to childhood maltreatment (CM) is associated with increased risk for developing substance use disorders (SUDs). CM exerts negative effects on cognitive abilities including intellectual performance, memory, attention, and executive function. Parallel cognitive impairments have been observed in SUDs. Hence, limited studies have examined the mediating effect of cognitive impairments in the relationship between CM and SUDs. In addition, most studies used concurrent self-report assessments in adult populations. Longitudinal studies that investigated the long-term consequences of CM on psychopathology, including SUDs, throughout childhood, adolescence, and adulthood are rare. Thus, the underlying developmental pathways between CM and SUDs are not clearly understood. In this article, we review the evidence that cognitive impairments mediate, at least in part, the relationship between CM and development of SUDs and propose a model that explains how CM increases the risk for SUDs through the development of a cognitive framework of vulnerability.

Variants of opioid system genes are associated with non-dependent opioid use and heroin dependence

BACKGROUND

Heroin addiction is a chronic, relapsing brain disease. Genetic factors are involved in the development of drug addiction. The aim of this study was to determine whether specific variants in genes of the opioid system are associated with non-dependent opioid use and heroin dependence.

METHODS

Genetic information from four subject groups was collected: non-dependent opioid users (NOD) [n=163]; opioid-dependent (OD) patients in methadone maintenance treatment (MMT) [n=143]; opioid-dependent MMT-resistant patients in heroin-assisted treatment (HAT) [n=138]; and healthy controls with no history of opioid use (HC) [n=153]. Eighty-two variants in eight opioid system genes were studied. To establish the role of these genes in (a) non-dependent opioid use, and (b) heroin dependence, the following groups were compared: HC vs. NOD; HC vs. OD (MMT+HAT); and NOD vs. OD (MMT+HAT).

RESULTS

Five unique SNPs in four genes showed nominally significant associations with non-dependent opioid use and heroin dependence. The association of the delta opioid receptor (OPRD1) intronic SNP rs2236861 with non-dependent opioid use (HC vs. NOD) remained significant after correction for multiple testing (OR=0.032; p_corrected=0.015). This SNP exhibited a significant gene-gene interaction with prepronociceptin (PNOC) SNP rs2722897 (OR=5.24; p_corrected=0.041) (HC vs. NOD).

CONCLUSIONS

This study identifies several new and some previously reported associations of variants with heroin dependence and with non-dependent opioid use, an important and difficult to obtain group not extensively studied previously. Further studies are warranted to confirm and elucidate the potential roles of these variants in the vulnerability to illicit drug use and drug addiction.

Trends and Progress in Reducing Teen Birth Rates and the Persisting Challenge of Eliminating Racial/Ethnic Disparities

PURPOSE

We examined progress made by the Milwaukee community toward achieving the Milwaukee Teen Pregnancy Prevention Initiative's aggressive 2008 goal of reducing the teen birth rate to 30 live births/1000 females aged 15-17 years by 2015. We further examined differential teen birth rates in disparate racial and ethnic groups.

METHOD

We analyzed teen birth count data from the Wisconsin Interactive Statistics on Health system and demographic data from the US Census Bureau. We computed annual 2003-2014 teen birth rates for the city and four racial/ethnic groups within the city (white non-Hispanic, black non-Hispanic, Hispanic/Latina, Asian non-Hispanic). To compare birth rates from before (2003-2008) and after (2009-2014) goal setting, we used a single-system design to employ two time series analysis approaches, celeration line, and three standard deviation (3SD) bands.

RESULTS

Milwaukee's teen birth rate dropped 54 % from 54.3 in 2003 to 23.7 births/1000 females in 2014, surpassing the goal of 30 births/1000 females 3 years ahead of schedule. Rate reduction following goal setting was statistically significant, as five of the six post-goal data points were located below the celeration line and points for six consecutive years (2010-2014) fell below the 3SD band. All racial/ethnic groups demonstrated significant reductions through at least one of the two time series approaches. The gap between white and both black and Hispanic/Latina teens widened.

CONCLUSION

Significant reduction has occurred in the overall teen birth rate of Milwaukee. Achieving an aggressive reduction in teen births highlights the importance of collaborative community partnerships in setting and tracking public health goals.

African-specific variability in the acetylcholine muscarinic receptor M4: association with cocaine and heroin addiction

AIM

This study was designed to determine whether polymorphisms in acetylcholine receptors contribute to opioid dependence and/or cocaine dependence.

PATIENTS & METHODS

The sample (n = 1860) was divided by drug and ancestry, and 55 polymorphisms (nine genes) were analyzed.

RESULTS

Of the 20 SNPs that showed nominally significant associations, the association of the African-specific CHRM4 SNP rs2229163 (Asn417=) with cocaine dependence survived correction for multiple testing (Pcorrected = 0.047). CHRM4 is located in a region of strong linkage disequilibrium on chromosome 11 that includes genes associated with schizophrenia. CHRM4 SNP rs2229163 is in strong linkage disequilibrium with several African-specific SNPs in DGKZ and AMBRA1.

CONCLUSION

Cholinergic receptors' variants may contribute to drug addiction and have a potential role as pharmacogenetic markers.

A Prospective Cohort Study of Influences on Externalizing Behaviors Across Childhood: Results From a Nurse Home Visiting Randomized Controlled Trial

OBJECTIVE

This study investigated genetic and environmental influences on behavior in a cohort of 600 children followed prenatally to 18 years.

METHOD

A randomized controlled trial of prenatal/infancy nurse home visits (NHV) was conducted in 600 predominantly African American mothers and their firstborn children from Memphis, TN. Mothers were assessed in pregnancy for mental health (MH), self-efficacy, and mastery. Mothers reported longitudinally on smoking and alcohol/drug use. The functional polymorphisms SLC6A4 5-HTTLPR, FKBP5 rs1360780 and DRD2/ANKK1 rs1800497 were genotyped together with 186 ancestry informative markers. Composite externalizing disorders (ED) continuous total scores from the mother-report Achenbach Child Behavior Checklist were included as dependent variables in regression analyses for time points 2, 6, 12, and 18 years.

RESULTS

Behaviors at younger ages strongly predicted later behaviors (p < .0001). Children whose mothers had high self-efficacy and had received NHV were better behaved at age 2 years. Poorer maternal MH adversely influenced ED up to 12 years, but at age 18 years, maternal mastery exerted a strong, positive effect (p = .0001). Maternal smoking was associated with worse ED at 6 and 18 years. Main and interactive effects of genetic polymorphisms varied across childhood: FKBP5 rs1360780 up to age 6, 5-HTTLPR from 6 to 12, and DRD2/ANKK1 rs1800497 from 2 to 18 years.

CONCLUSION

Our study suggests that maternal MH and resilience measured in pregnancy have long-lasting effects on child behavior. Maternal smoking across childhood and genetic factors also play a role. NHV had a positive effect on early behavior. Our findings have implications for prevention of pathological behaviors in adulthood. Clinical trial registration information-Age-17 Follow-Up of Home Visiting Intervention; http://clinicaltrials.gov/; NCT00708695.

Glutamatergic and GABAergic susceptibility loci for heroin and cocaine addiction in subjects of African and European ancestry

BACKGROUND

Drug addiction, a leading health problem, is a chronic brain disease with a significant genetic component. Animal models and clinical studies established the involvement of glutamate and GABA neurotransmission in drug addiction. This study was designed to assess if 258 variants in 27 genes of these systems contribute to the vulnerability to develop drug addiction.

METHODS

Four independent analyses were conducted in a sample of 1860 subjects divided according to drug of abuse (heroin or cocaine) and ancestry (African and European).

RESULTS

A total of 11 SNPs in eight genes showed nominally significant associations (P<0.01) with heroin and/or cocaine addiction in one or both ancestral groups but the associations did not survive correction for multiple testing. Of these SNPs, the GAD1 upstream SNP rs1978340 is potentially functional as it was shown to affect GABA concentrations in the cingulate cortex. In addition, SNPs GABRB3 rs7165224; DBI rs12613135; GAD1 SNPs rs2058725, rs1978340, rs2241164; and GRIN2A rs1650420 were previously reported in associations with drug addiction or related phenotypes.

CONCLUSIONS

The study supports the involvement of genetic variation in the glutamatergic and GABAergic systems in drug addiction with partial overlap in susceptibility loci between cocaine and heroin addiction.

Stimulants and Cannabis Use Among a Marginalized Population in British Columbia, Canada: Role of Trauma and Incarceration

High rates of substance use, especially cannabis and stimulant use, have been associated with homelessness, exposure to trauma, and involvement with the criminal justice system. This study explored differences in substance use (cannabis vs. stimulants) and associations with trauma and incarceration among a homeless population. Data were derived from the BC Health of the Homeless Study (BCHOHS), carried out in three cities in British Columbia, Canada. Measures included sociodemographic information, the Maudsley Addiction Profile (MAP), the Childhood Trauma Questionnaire (CTQ), and the Mini International Neuropsychiatric Interview (MINI) Plus. Stimulant users were more likely to be female (43%), using multiple substances (3.2), and engaging in survival sex (14%). Cannabis users had higher rates of lifetime psychotic disorders (32%). Among the incarcerated, cannabis users had been subjected to greater emotional neglect (p < .05) and one in two cannabis users had a history of lifetime depressive disorders (p < .05). Childhood physical abuse and Caucasian ethnicity were also associated with greater crack cocaine use. One explanation for the results is that a history of childhood abuse may lead to a developmental cascade of depressive symptoms and other psychopathology, increasing the chances of cannabis dependence and the development of psychosis.

Synaptic Plasticity and Signal Transduction Gene Polymorphisms and Vulnerability to Drug Addictions in Populations of European or African Ancestry

AIM

Drug addiction is characterized, in part, by deregulation of synaptic plasticity in circuits involved in reward, stress, cue learning, and memory. This study was designed to assess whether 185 variants in 32 genes central to synaptic plasticity and signal transduction contribute to vulnerability to develop heroin and/or cocaine addiction.

METHODS

Analyses were conducted in a sample of 1860 subjects divided according to ancestry (African and European) and drug of abuse (heroin or cocaine).

RESULTS

Eighteen SNPs in 11 genes (CDK5R1, EPHA4, EPHA6, FOSL2, MAPK3, MBP, MPDZ, NFKB1, NTRK2, NTSR1, and PRKCE) showed significant associations (P < 0.01), but the signals did not survive correction for multiple testing. SNP rs230530 in the NFKB1 gene, encoding the transcription regulator NF-kappa-B, was the only SNP indicated in both ancestry groups and both addictions. This SNP was previously identified in association with alcohol addiction. SNP rs3915568 in NTSR1, which encodes neurotensin receptor, and SNP rs1389752 in MPDZ, which encodes the multiple PDZ domain protein, were previously associated with heroin addiction or alcohol addiction, respectively.

CONCLUSIONS

The study supports the involvement of genetic variation in signal transduction pathways in heroin and cocaine addiction and provides preliminary evidence suggesting several new risk or protective loci that may be relevant for diagnosis and treatment success.

Dopaminergic pathway polymorphisms and heroin addiction: further support for association of CSNK1E variants

BACKGROUND & AIM

The dopaminergic pathways have been implicated in the etiology of drug addictions. The aim of this study was to determine if variants in dopaminergic genes are associated with heroin addiction.

MATERIALS & METHODS

The study includes 828 former heroin addicts and 232 healthy controls, of predominantly European ancestry. Ninety seven SNPs (13 genes) were analyzed.

RESULTS

Nine nominally significant associations were observed at CSNK1E, ANKK1, DRD2 and DRD3.

CONCLUSION

The results support our previous report of association of CSNK1E SNP rs1534891 with protection from heroin addiction. CSNK1E interacts with circadian rhythms and DARPP-32 and has been implicated in negative regulation of sensitivity to opioids in rodents. It may be a target for drug addiction treatment. Original submitted 8 August 2014; Revision submitted 8 October 2014.

Susceptibility loci for heroin and cocaine addiction in the serotonergic and adrenergic pathways in populations of different ancestry

BACKGROUND

Drug addiction is influenced by genetic factors.

AIM

To determine if genetic variants in the serotonergic and adrenergic pathways are associated with heroin and/or cocaine addiction.

SUBJECTS & METHODS

The study examined 140 polymorphisms in 19 genes in 1855 subjects with predominantly European or African ancestries.

RESULTS

A total of 38 polymorphisms (13 genes) showed nominal associations, including novel associations in S100A10 (p11) and SLC18A2 (VMAT2). The association of HTR3B SNP rs11606194 with heroin addiction in the European ancestry subgroup remained significant after correction for multiple testing (p(corrected) = 0.04).

CONCLUSION

The study strengthens our previous findings of association of polymorphisms in HTR3A, HTR3B and ADRA1A. The study suggests partial overlap in genetic susceptibility between populations of different ancestry and between heroin and cocaine addiction.

Dissociation of heroin-induced emotional dysfunction from psychomotor activation and physical dependence among inbred mouse strains

RATIONALE

Opiate addiction is a brain disorder emerging through repeated intoxication and withdrawal episodes. Epidemiological studies also indicate that chronic exposure to opiates may lead in susceptible individuals to the emergence of depressive symptoms, strongly contributing to the severity and chronicity of addiction. We recently established a mouse model of heroin abstinence, characterized by the development of depressive-like behaviors following chronic heroin exposure.

OBJECTIVES

While genetic factors regulating immediate behavioral responses to opiates have been largely investigated, little is known about their contribution to long-term emotional regulation during abstinence. Here, we compared locomotor stimulation and physical dependence induced by heroin exposure, as well as emotional dysfunction following abstinence, across mice strains with distinct genetic backgrounds.

METHODS

Mice from three inbred strains (C57BL/6J, Balb/cByJ, and 129S2/SvPas) were exposed to an escalating chronic heroin regimen (10-50 mg/kg). Independent cohorts were used to assess drug-induced locomotor activity during chronic treatment, naloxone-precipitated withdrawal at the end of chronic treatment, and emotional-like responses after a 4-week abstinence period.

RESULTS

Distinct behavioral profiles were observed across strains during heroin treatment, with no physical dependence and low locomotor stimulation in 129S2/SvPas. In addition, different behavioral impairments developed during abstinence across the three strains, with increased despair-like behavior in 129S2/SvPas and Balb/cByJ, and low sociability in 129S2/SvPas and C57BL/6J.

CONCLUSIONS

Our results indicate that depressive-like behaviors emerge during heroin abstinence, whatever the severity of immediate behavioral responses to the drug. In addition, inbred mouse strains will allow studying several aspects of mood-related deficits associated with addiction.

Associations between childhood trauma and non-fatal overdose among people who inject drugs

INTRODUCTION

Although people who inject drugs (IDU) remain at a high risk of accidental overdose, interventions that address overdose remain limited. Accordingly there is a continuing need to identify psychological and social factors that shape overdose risk. Despite being reported frequently among IDU, childhood trauma has received little attention as a potential risk factor for overdose. This study aims to evaluate relationships between non-fatal overdose and five forms of childhood maltreatment among a cohort of IDU in Vancouver, Canada.

METHODS

Data was obtained from two prospective cohorts of IDU between December 2005 and May 2013. Multivariate generalized estimating equations (GEEs) were used to explore relationships between five forms of childhood trauma and non-fatal overdose, adjusting for potential confounders.

RESULTS

During the study period, 1697 IDU, including 552 (32.5%) women, were followed up. At baseline, 1136 (67.0%) participants reported at least one form of childhood trauma, while 4-9% reported a non-fatal overdose at each semi-annual follow-up. In multivariate analyses, physical [adjusted odds ratio (AOR): 1.36, 95% confidence interval (CI): 1.08-1.71], sexual (AOR: 1.48, CI: 1.17-1.87), and emotional abuse (AOR: 1.54, CI: 1.22-1.93) and physical neglect (AOR: 1.28, CI: 1.01-1.62) were independently associated with non-fatal overdose (all p<0.05).

CONCLUSIONS

Childhood trauma was common among participants, and reporting an experience of trauma was positively associated with non-fatal overdose. These findings highlight the need to provide intensive overdose prevention to trauma survivors and to incorporate screening for childhood trauma into health and social programs tailored to IDU.

Overlapping dopaminergic pathway genetic susceptibility to heroin and cocaine addictions in African Americans

Drugs of abuse activate the mesolimbic dopaminergic pathway. Genetic variations in the dopaminergic system may contribute to drug addiction. Several processes are shared between cocaine and heroin addictions but some neurobiological mechanisms may be specific. This study examined the association of 98 single nucleotide polymorphisms in 13 dopamine-related genes with heroin addiction (OD) and/or cocaine addiction (CD) in a sample of 801 African Americans (315 subjects with OD ± CD, 279 subjects with CD, and 207 controls). Single-marker analyses provided nominally significant evidence for associations of 24 SNPs) in DRD1, ANKK1/DRD2, DRD3, DRD5, DBH, DDC, COMT and CSNK1E. A DRD2 7-SNPs haplotype that includes SNPs rs1075650 and rs2283265, which were shown to alter D2S/D2L splicing, was indicated in both addictions. The Met allele of the functional COMT Val158Met was associated with protection from OD. None of the signals remained significant after correction for multiple testing. The study results are in accordance with the results of previous studies, including our report of association of DRD1 SNP rs5326 with OD. The findings suggest the presence of an overlap in genetic susceptibility for OD and CD, as well as shared and distinct susceptibility for OD in subjects of African and European descent.

Consequences of repeated ethanol exposure during early or late adolescence on conditioned taste aversions in rats

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Adolescent Intermittent Ethanol (AIE) resulted in attenuated CTA in adulthood.

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AIE in late adolescence resulted in greater CTA attenuation 2 days post-exposure.

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All AIE animals were equally insensitive when tested 3 weeks post-exposure.

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No metabolic tolerance was noted following AIE.

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AIE results in a decreased sensitivity to aversive effects of ethanol in adulthood.

Alcohol use is prevalent during adolescence, yet little is known about possible long-lasting consequences. Recent evidence suggests that adolescents are less sensitive than adults to ethanol's aversive effects, an insensitivity that may be retained into adulthood after repeated adolescent ethanol exposure. This study assessed whether intermittent ethanol exposure during early or late adolescence (early-AIE or late-AIE, respectively) would affect ethanol conditioned taste aversions 2 days (CTA1) and >3 weeks (CTA2) post-exposure using supersaccharin and saline as conditioning stimuli (CS), respectively. Pair-housed male Sprague-Dawley rats received 4 g/kg i.g. ethanol (25%) or water every 48 h from postnatal day (P) 25–45 (early AIE) or P45-65 (late AIE), or were left non-manipulated (NM). During conditioning, 30 min home cage access to the CS was followed by 0, 1, 1.5, 2 or 2.5 g/kg ethanol i.p., with testing 2 days later. Attenuated CTA relative to controls was seen among early and late AIE animals at both CTA1 and CTA2, an effect particularly pronounced at CTA1 after late AIE. Thus, adolescent exposure to ethanol was found to induce an insensitivity to ethanol CTA seen soon after exposure and lasting into adulthood, and evident with ethanol exposures not only early but also later in adolescence.

Co-occurrence of psychotic experiences and common mental health conditions across four racially and ethnically diverse population samples

BACKGROUND

Prior research with racially/ethnically homogeneous samples has demonstrated widespread co-occurrence of psychotic experiences (PEs) and common mental health conditions, particularly multi-morbidity, suggesting that psychosis may be related to the overall severity of psychiatric disorder rather than any specific subtype. In this study we aimed to examine whether PEs are associated with the presence of specific disorders or multi-morbidity of co-occurring disorders across four large racially/ethnically diverse samples of adults in the USA.

METHOD

Data were drawn from the National Comorbidity Survey Replication (NCS-R), the National Survey of American Life (NSAL) and separately from the Asian and Latino subsamples of the National Latino and Asian American Study (NLAAS). Logistic regression models were used to examine the relationship between PEs and individual subtypes of DSM-IV disorder, and to test for a linear dose-response relationship between the number of subtypes and PEs.

RESULTS

Prevalence of PEs was moderately greater among individuals with each subtype of disorder in each data set [odds ratios (ORs) 1.8-3.8], although associations were only variably significant when controlling for clinical and demographic variables. However, the sum of disorder subtypes was related to odds for PEs in a linear dose-response fashion across all four samples.

CONCLUSIONS

PEs are related primarily to the extent or severity of psychiatric illness, as indicated by the presence of multiple psychiatric disorders, rather than to any particular subtype of disorder in these data. This relationship applies to the general population and across diverse racial/ethnic groups.

Family history of alcohol and drug abuse, childhood trauma, and age of first drug injection

BACKGROUND

Childhood maltreatment may lead to development of future substance use; however the contributions of a family history of substance use is unclear.

OBJECTIVES

To better understand the relationship between childhood abuse, family history of alcohol and drug abuse, and injecting drug use initiation in a cohort of chronic opioid users.

METHODS

A cross-sectional survey of long-term and difficult to treat intravenous opiate users of the North American Opiate Medication Initiative (NAOMI) cohort was conducted in two Canadian cities (Vancouver and Montreal). For the analysis, we selected a subsample (n = 87) of the population reported experiencing childhood abuse and completed a 12-month follow up. The sample was 41.4% female and 14.9% First Nations, with a mean age of 38 years. This sample then completed the Childhood Trauma Questionnaire (CTQ) and the Addiction Severity Index (ASI) beside others.

RESULTS

Maternal alcohol and drug use was significantly associated with childhood sexual abuse, emotional abuse, and physical neglect. Paternal alcohol and drug use was significantly associated with childhood physical abuse. Increased severity of all types of childhood trauma was related to an earlier age of first injection. CONCLUSIONS/IMPORTANCE: Family history of drug and alcohol use is strongly associated with childhood trauma, which may, in turn, lead to an earlier initiation to the dangerous routes of drug injection.

Stress-related genes and heroin addiction: a role for a functional FKBP5 haplotype

BACKGROUND

Stress is a critical risk factor affecting both the development of and the relapse to drug addictions. Drug addictions are caused by genetic, environmental and drug-induced factors. The objective of this hypothesis-driven association study was to determine if genetic variants in stress-related genes are associated with heroin addiction.

METHODS

112 selected genetic variants in 26 stress-related genes were genotyped in 852 case subjects and 238 controls of predominantly European ancestry. The case subjects are former heroin addicts with a history of at least one year of daily multiple uses of heroin, treated at a methadone maintenance treatment program (MMTP). The two most promising SNPs were subsequently tested in an African-American sample comprising of 314 cases and 208 control individuals.

RESULTS

Nineteen single nucleotide polymorphisms (SNPs) in 9 genes (AVP, AVPR1A, CRHR1, CRHR2, FKBP5, GAL, GLRA1, NPY1R and NR3C2) showed nominally significant association with heroin addiction. The associations of two FKBP5 SNPs that are part of one haplotype block, rs1360780 (intron 2) and rs3800373 (the 3' untranslated region), remained significant after correction for multiple testing (Pcorrected=0.03; OR=2.35, Pcorrected=0.0018; OR=2.85, respectively). The two SNPs also showed nominally significant association (P<0.05) with heroin addiction in an independent African-American cohort. FKBP5 is a co-chaperone that regulates glucocorticoid sensitivity. These FKBP5 SNPs were previously associated with diverse affective disorders and showed functional differences in gene expression and stress response. This study also supports our and others' previous reports of association of the GAL SNP rs694066 and the AVPR1A SNPs rs11174811, rs1587097 and rs10784339 with heroin and general drug addiction, respectively.

CONCLUSIONS

This study suggests that variations in the FKBP5 gene contribute to the development of opiate addiction by modulating the stress response. These findings may enhance the understanding of the interaction between stress and heroin addiction.

Drug addiction and stress-response genetic variability: association study in African Americans

Stress is a significant risk factor in the development of drug addictions and in addiction relapse susceptibility. This hypothesis-driven study was designed to determine if specific SNPs in genes related to stress response are associated with heroin and/or cocaine addiction in African Americans. The analysis included 27 genes (124 SNPs) and was performed independently for each addiction. The sample consisted of former heroin addicts in methadone maintenance treatment (n = 314), cocaine addicts (n = 281), and controls (n = 208). Fourteen SNPs showed nominally significant association with heroin addiction (p < 0.05), including the African-specific, missense SNP rs5376 (Asn334Ser) in the galanin receptor type 1 gene (GALR1) and the functional FKBP5 intronic SNP rs1360780. Thirteen SNPs showed association with cocaine addiction, including the synonymous SNPs rs237902, in the oxytocin receptor gene (OXTR), and rs5374 in GALR1. No signal remained significant after correction for multiple testing. Four additional SNPs (GALR1 rs2717162, AVP rs2282018, CRHBP rs1875999, and NR3C2 rs1040288) were associated with both addictions and may indicate common liability. The study provides preliminary evidence for novel association of variants in several stress-related genes with heroin and/or cocaine addictions and may enhance the understanding of the interaction between stress and addictions.

Association of genetic variation in pharmacodynamic factors with methadone dose required for effective treatment of opioid addiction

AIM

The interindividual variability in the dose required for effective methadone maintenance treatment (MMT) for opioid addiction may be influenced in part by genetic variations in genes encoding pharmacodynamic factors of methadone. This study was conducted to identify some of these variants.

MATERIALS & METHODS

This study focused on 11 genes encoding components of the opioidergic (OPRM1, POMC and ARRB2), the dopaminergic (ANKK1 and DRD2) and the glutamatergic pathways (GRIN1 and GRIN2A), as well as the neurotrophin system (NGFB, BDNF, NTRK1 and NTRK2). The study includes 227 Israeli patients undergoing stable MMT.

RESULTS

Out of the 110 variants analyzed, 12 SNPs (in BDNF, NTRK2, OPRM1, DRD2 and ANKK1) were associated with methadone dose (nominal p < 0.05). Of these SNPs, ANKK1 rs7118900 and DRD2 rs2283265 are known to affect gene expression. Logistic regression of five representative SNPs discriminated between individuals requiring a methadone dose of >120 mg/day and <120 mg/day (p = 0.019), and showed moderate sensitivity and specificity (AUC of 0.63 in receiver operating characteristic analysis).

CONCLUSION

This data should stimulate further research on the potential influence and clinical significance of these variants on MMT.

The impact of childhood emotional abuse on violence among people who inject drugs

INTRODUCTION AND AIMS

Childhood emotional abuse is a known risk factor for various poor social and health outcomes. While people who inject drugs (IDU) report high levels of violence, in addition to high rates of childhood maltreatment, the relationship between childhood emotional abuse and later life violence within this population has not been examined.

DESIGN AND METHODS

Cross-sectional data were derived from an open prospective cohort of IDU in Vancouver, Canada. Childhood emotional abuse was measured using the Childhood Trauma Questionnaire. We used multivariate logistic regression to examine potential associations between childhood emotional abuse and being a recent victim or perpetrator of violence.

RESULTS

Between December 2005 and May 2013, 1437 IDU were eligible for inclusion in this analysis, including 465 (32.4%) women. In total, 689 (48.0%) reported moderate to severe history of childhood emotional abuse, whereas 333 (23.2%) reported being a recent victim of violence and 173 (12.0%) reported being a recent perpetrator of violence. In multivariate analysis, being a victim of violence (adjusted odds ratio = 1.49, 95% confidence interval 1.15-1.94) and being a perpetrator of violence (adjusted odds ratio = 1.58, 95% confidence interval 1.12-2.24) remained independently associated with childhood emotional abuse.

DISCUSSION AND CONCLUSIONS

We found high rates of childhood emotional abuse and subsequent adult violence among this sample of IDU. Emotional abuse was associated with both victimisation and perpetration of violence. These findings highlight the need for policies and programmes that address both child abuse and historical emotional abuse among adult IDU.

Genetic influences on the development of alcoholism

Alcoholism has a substantial heritability yet the detection of specific genetic influences has largely proved elusive. The strongest findings are with genes encoding alcohol metabolizing enzymes. A few candidate genes such as GABRA2 have shown robust associations with alcoholism. Moreover, it has become apparent that variants in stress-related genes such as CRHR1, may only confer risk in individuals exposed to trauma, particularly in early life. Over the past decade there have been tremendous advances in large scale SNP genotyping technologies allowing for genome-wide associations studies (GWAS). As a result, it is now recognized that genetic risk for alcoholism is likely to be due to common variants in very many genes, each of small effect, although rare variants with large effects might also play a role. This has resulted in a paradigm shift away from gene centric studies toward analyses of gene interactions and gene networks within biologically relevant pathways.

Longitudinal associations between types of childhood trauma and suicidal behavior among substance users: a cohort study

OBJECTIVES

We examined the longitudinal associations between different types and severities of childhood trauma and suicide attempts among illicit drug users.

METHODS

Data came from 2 prospective cohort studies of illicit drug users in Vancouver, Canada, in 2005 to 2010. We used recurrent event proportional means models to estimate adjusted and weighted associations between types and severities of childhood maltreatment and suicide attempts.

RESULTS

Of 1634 participants, 411 (25.2%) reported a history of suicidal behavior at baseline. Over 5 years, 80 (4.9%) participants reported 97 suicide attempts, a rate of 2.6 per 100 person-years. Severe to extreme levels of sexual abuse (adjusted hazard ratio [AHR] = 2.5; 95% confidence interval [CI] = 1.4, 4.4), physical abuse (AHR = 2.0; 95% CI = 1.1, 3.8), and emotional abuse (AHR = 3.5; 95% CI = 1.4, 8.7) predicted suicide attempts. Severe forms of physical and emotional neglect were not significantly associated with an increased risk of suicidal behavior.

CONCLUSIONS

Severe sexual, physical, and emotional childhood abuse confer substantial risk of repeated suicidal behavior in adulthood. Illicit drug users require intensive secondary suicide prevention efforts, particularly among those with a history of childhood trauma.

Case-control association analysis of polymorphisms in the δ-opioid receptor, OPRD1, with cocaine and opioid addicted populations

BACKGROUND

Addiction susceptibility and treatment responsiveness are greatly influenced by genetic factors. Sequence variation in genes involved in the mechanisms of drug action have the potential to influence addiction risk and treatment outcome. The opioid receptor system is involved in mediating the rewarding effects of cocaine and opioids. The μ-opioid receptor (MOR) has traditionally been considered the primary target for opioid addiction. The MOR, however, interacts with and is regulated by many known MOR interacting proteins (MORIPs), including the δ-opioid receptor (DOR).

METHODS

The present study evaluated the contribution of OPRD1, the gene encoding the DOR, to the risk of addiction to opioids and cocaine. The association of OPRD1 polymorphisms with both opioid addiction (OA) and cocaine addiction (CA) was analyzed in African American (OA n=336, CA n=503) and European American (OA n=1007, CA n=336) populations.

RESULTS

The primary finding of this study is an association of rs678849 with cocaine addiction in African Americans (allelic p=0.0086). For replication purposes, this SNP was analyzed in a larger independent population of cocaine addicted African Americans and controls and the association was confirmed (allelic p=4.53 × 10(-5); n=993). By performing a meta-analysis on the expanded populations, the statistical evidence for an association was substantially increased (allelic p=8.5 × 10(-7)) (p-values non-FDR corrected).

CONCLUSION

The present study suggests that polymorphisms in OPRD1 are relevant for cocaine addiction in the African American population and provides additional support for a broad role for OPRD1 variants in drug dependence.

Estimating ancestral proportions in a multi-ethnic US sample: implications for studies of admixed populations

This study was designed to determine the ancestral composition of a multi-ethnic sample collected for studies of drug addictions in New York City and Las Vegas, and to examine the reliability of self-identified ethnicity and three-generation family history data. Ancestry biographical scores for seven clusters corresponding to world major geographical regions were obtained using STRUCTURE, based on genotypes of 168 ancestry informative markers (AIMs), for a sample of 1,291 African Americans (AA), European Americans (EA), and Hispanic Americans (HA) along with data from 1,051 HGDP-CEPH ‘diversity panel’ as a reference. Self-identified ethnicity and family history data, obtained in an interview, were accurate in identifying the individual major ancestry in the AA and the EA samples (approximately 99% and 95%, respectively) but were not useful for the HA sample and could not predict the extent of admixture in any group. The mean proportions of the combined clusters corresponding to European and Middle Eastern populations in the AA sample, revealed by AIMs analysis, were 0.13. The HA subjects, predominantly Puerto Ricans, showed a highly variable hybrid contribution pattern of clusters corresponding to Europe (0.27), Middle East (0.27), Africa (0.20), and Central Asia (0.14). The effect of admixture on allele frequencies is demonstrated for two single-nucleotide polymorphisms (118A > G, 17 C > T) of the mu opioid receptor gene (OPRM1). This study reiterates the importance of AIMs in defining ancestry, especially in admixed populations.

The genetic basis of addictive disorders

Addictions are common, chronic, and relapsing diseases that develop through a multistep process. The impact of addictions on morbidity and mortality is high worldwide. Twin studies have shown that the heritability of addictions ranges from 0.39 (hallucinogens) to 0.72 (cocaine). Twin studies indicate that genes influence each stage from initiation to addiction, although the genetic determinants may differ. Addictions are by definition the result of gene × environment interaction. These disorders, which are in part volitional, in part inborn, and in part determined by environmental experience, pose the full range of medical, genetic, policy, and moral challenges. Gene discovery is being facilitated by a variety of powerful approaches, but is in its infancy. It is not surprising that the genes discovered so far act in a variety of ways: via altered metabolism of drug (the alcohol and nicotine metabolic gene variants), via altered function of a drug receptor (the nicotinic receptor, which may alter affinity for nicotine but as discussed may also alter circuitry of reward), and via general mechanisms of addiction (genes such as monoamine oxidase A and the serotonin transporter that modulate stress response, emotion, and behavioral control). Addiction medicine today benefits from genetic studies that buttress the case for a neurobiologic origin of addictive behavior, and some general information on familially transmitted propensity that can be used to guide prevention. A few well-validated, specific predictors such as OPRM1, ADH1B, ALDH2, CHRNA5, and CYP26 have been identified and can provide some specific guidance, for example, to understand alcohol-related flushing and upper GI cancer risk (ADH1B and AKLDH2), variation in nicotine metabolism (CYP26), and, potentially, naltrexone treatment response (OPRM1). However, the genetic predictors available are few in number and account for only a small portion of the genetic variance in liability, and have not been integrated into clinical nosology or care.

The influence of gene-environment interactions on the development of alcoholism and drug dependence

Alcoholism and drug dependence are common psychiatric disorders with a heritability of about 50%; therefore genetic and environmental influences are equally important. Early-life stress is a predictor of adolescent problem drinking/drug use and alcohol/drug dependence in adulthood, but moderating factors governing the availability of alcohol/drug are important. The risk-resilience balance for addiction may be due in part to the interaction between genetic variation and environment stressors (G × E); this has been confirmed by twin studies of inferred genetic risk. Measured genotype studies to detect G × E effects have used a range of alcohol consumption and diagnostic phenotypes and stressors ranging from early-life to adulthood past year life events. In this article, the current state of the field is critically reviewed and suggestions are put forth for future research.

A C17T polymorphism in the mu opiate receptor is associated with quantitative measures of drug use in African American women

Previous studies of the association of the C17T polymorphism of the mu opiate receptor gene with substance dependence compared cases with substance dependence to controls and usually found no significant association. However, the studies were limited by small sample size-no study had more than 12 subjects with the TT genotype, a genotype that is rare in white and Asian subjects. Moreover, drug use is not dichotomous but follows a spectrum from non-use to modest, intermittent use, to use several times daily. We asked whether the Kreek-McHugh-Schluger-Kellogg (KMSK) scales for alcohol, cocaine, opiates and tobacco that quantify substance use during the time of a subject's maximal use might be more sensitive measures than dichotomous outcomes. We administered the KMSK scales and completed C17T genotyping on 1009 human immunodeficiency virus (HIV)-infected and 469 HIV-uninfected women in The Women's Interagency HIV Study, an ongoing study of HIV in women. Forty-two of the 697 African American, 1 of the 182 Hispanic and none of the 161 white women had the TT genotype. KMSK cocaine, alcohol and tobacco scores were significantly higher in the African American women with the TT genotype (P = 0.008, 0.0001, and 0.006, respectively), but opiate scores were not. Ordinal regression models controlling for HIV serostatus, age, education, and income had odds ratios for the TT genotype for predicting alcohol, tobacco, cocaine and opiates scores of 2.1 (P = 0.02), 2.4 (P = 0.0004), 2.0 (P = 0.03) and 1.9 (P = 0.07). We conclude that the TT genotype of OPRM1 may increase the risk of substance use and abuse.

Genetic and environmental determinants of stress responding

The risk for alcohol dependence throughout development is determined by both genetic and environmental factors. Genetic factors that are thought to modulate this risk act on neurobiological pathways regulating reward, impulsivity, and stress responses. For example, genetic variations in pathways using the brain signaling molecule (i.e., neurotransmitter) dopamine, which likely mediate alcohol's rewarding effects, and in two hormonal systems involved in the stress response (i.e., the hypothalamic-pituitary-adrenal axis and the corticotropin-releasing factor system) affect alcoholism risk. This liability is modified further by exposure to environmental risk factors, such as environmental stress and alcohol use itself, and the effects of these factors may be enhanced in genetically vulnerable individuals. The transition from alcohol use to dependence is the result of complex interactions of genes, environment, and neurobiology, which fluctuate throughout development. Therefore, the relevant genetic and environmental risk factors may differ during the different stages of alcohol initiation, abuse, and dependence. The complex interaction of these factors is yet to be fully elucidated, and translational studies, ranging from animal studies to research in humans, and well-characterized longitudinal studies are necessary to further understand the development of alcohol dependence.