Association between DRD2, 5-HTTLPR, and ALDH2 genes and specific personality traits in alcohol- and opiate-dependent patients

Oxytocin level among patients with opioid use disorder and its correlation with personality traits and perceived childhood trauma

Background

Personality traits and perceived childhood maltreatment are of the predictors of substance use disorder development. Many studies have discussed oxytocin effect on personality traits and its relation with childhood trauma and how both affect the addictive process. The main aim was to compare oxytocin level between patients with opioid use disorder and controls and the potential association of oxytocin level with the basic dimensions of personality traits and perceived childhood adverse experiences in patients group. Forty male patients with opioid use disorder and 40 healthy controls matched in age and gender were assessed and compared regarding serum oxytocin level by ELISA, personality traits using Temperament and character inventory - revised (TCI- R) scale, and childhood adverse events using childhood trauma questionnaire.

Results

A significant difference between the patient group and the control group regarding the serum oxytocin level was found. Negative correlation with p-value <0.05 between oxytocin level and each of novelty seeking, and harm avoidance, in addition to a positive correlation between oxytocin level and each of reward dependence, self-directedness, and cooperativeness items of (TCR-R), among cases were found. Cases did not show statistically significant difference in oxytocin level between different Childhood Trauma Questionnaire (CTQ) items.

Conclusions

The interaction between serum oxytocin levels, personality traits, and childhood trauma has to be considered in management with heroin-dependent patients as it plays a crucial role.

Relationship of DRD5 and MAO-B VNTR polymorphisms with paranoid and antisocial personality disorders in polydrug users

Although multiple studies have shown the role genetics plays in personality disorders and in addictions, few have studied the genetic aspects of their comorbidity. Here, we carried out a cross-sectional study in a sample comprising 303 Caucasian polydrug-consuming patients. The presence of personality disorders was evaluated using the International Personality Disorder Examination, and genes related to dopamine, serotonin and monoamine oxidase (MAO) were genotyped. A significant relationship was observed between the bp 279 DRD5 variable number of tandem repeat (VNTR) polymorphism and paranoid personality disorder OR 95 % CI = 2.186 1.074 ; 4.449 ; p = 0.006 . The bp 182 OR 95 % CI = 0.407 0.178 ; 0.931 ; p = 0.033 and bp 184 OR 95 % CI = 0.391 0.188 ; 0.813 ; p = 0.012 alleles of the MAOB VNTR were also associated with antisocial personality disorder. Among patients with addictions, paranoid personality disorder should also be considered in addition to the importance of antisocial and borderline personality disorders. The higher frequency of the bp 279 DRD5 VNTR allele found in patients with paranoid personality disorder, as well as the associations between alleles of the MAOB VNTR and antisocial personality disorder, support the monoaminergic bases of these personality disorders, especially when dealing with patients with addictions.

Positive associations between cannabis and alcohol use polygenic risk scores and phenotypic opioid misuse among African-Americans

BACKGROUND

This study examined whether polygenic risk scores (PRS) for lifetime cannabis and alcohol use were associated with misusing opioids, and whether sex differences existed in these relations in an urban, African-American sample.

METHODS

Data were drawn from three cohorts of participants (N = 1,103; 45% male) who were recruited in first grade as part of a series of elementary school-based, universal preventive intervention trials conducted in a Mid-Atlantic region of the U.S. In young adulthood, participants provided a DNA sample and reported on whether they had used heroin or misused prescription opioids in their lifetime. Three substance use PRS were computed based on prior GWAS: lifetime cannabis use from Pasman et al. (2018), heavy drinking indexed via maximum number of drinks from Gelernter et al. (2019), and alcohol consumption from Kranzler et al. (2019).

RESULTS

Higher PRS for lifetime cannabis use, greater heavy drinking, and greater alcohol consumption were associated with heightened risk for misusing opioids among the whole sample. Significant sex by PRS interactions were also observed such that higher PRS for heavy drinking and alcohol consumption were associated with a greater likelihood of opioid misuse among males, but not females.

CONCLUSION

Our findings further elucidate the genetic contributions to misusing opioids by showing that the genetics of cannabis and alcohol consumption are associated with lifetime opioid misuse among young adults, though replication of our findings is needed.

Association of Serotonergic Pathway Gene Polymorphisms With Behavioral Parameters in Patients With Opioid Dependence

Background and aims Opioid dependence is a chronic, relapsing substance use disorder with a multifactorial etiology, including a genetic component. Serotonin pathway gene polymorphisms have been an important focus of research for psychiatric disorders, including substance use disorders. This study aimed to identify the association of serotonin pathway gene polymorphisms with self-harm, depressive symptoms, impulsiveness, and aggression in patients with opioid dependence. Method The study group comprised 366 subjects with opioid dependence and 200 healthy volunteers. Patients were assessed for a history of self-harm, depressive symptoms, impulsiveness, and aggression using standard tools. Genomic DNA was used for genotyping of four polymorphisms - 5-HTTLPR, STin2 VNTR, TPH1 A218C, and TPH2 G703T. Results The short allele of 5-HTTLPR polymorphism showed a significant difference between cases (59.8%) and controls (40.1%) (p=0.001) and revealed an association with age at opioid dependence (p=0.033). There was a borderline significance of the short allele of 5-HTTLPR with the duration of opioid use (p=0.061) and non-plan impulsivity (p=0.076), suggesting a role of 5-HTTLPR in the susceptibility of opioid dependence. The other markers did not differ between cases and controls. However, the STin2A polymorphism revealed a significant association with anger scores, which may indicate its role in aggressive behavior. Conclusions The present study, the first of its kind, suggests an association of 5-HTTLPR polymorphism with opioid dependence and STin2A polymorphism with aggressive behavior among opioid-dependence patients, signifying the role of these markers in our patient population.

Molecular genetics of neurotransmitters and neuropeptides involved in Internet use disorders including first insights on a potential role of hypothalamus' oxytocin hormone

This chapter covers the phenomenon of Internet use disorders (IUDs) and putative associations with different neurotransmitter and neuropeptide systems. Genes coding for such messengers can be seen as an important starting point in the complicated quest to understand human behavior including new phenomena such as IUDs. Therefore, a special focus of this chapter will lie on individual differences in molecular genetic underpinnings of neurotransmitter and neuropeptide systems and their associations with individual differences in tendencies towards IUDs. By shedding light on these associations, putative predisposing molecular genetic factors for the emergence and maintenance of IUDs can be carved out. Therefore, first an introduction to IUDs and a model that can guide research on putative associations of IUDs with different specific neurotransmitters and neuropeptides will be presented. Subsequently, twin studies on the heritability of IUDs are reviewed. Finally, studies on differences in molecular genetic predispositions and their associations with differences in IUDs will be presented and discussed, including targets related to the dopaminergic and serotonergic system as well as the hypothalamic neuropeptide oxytocin. The chapter closes with a conclusion about what is already known and what needs to be investigated in future studies to gain further insights into putative associations between molecular genetic markers and IUDs.

Pharmacotherapeutic management of co-morbid alcohol and opioid use

Opioid use disorder (OUD) and alcohol use disorder (AUD) are two highly prevalent substance-related disorders worldwide. Co-use of the substances is also quite prevalent, yet there are no pharmacological treatment approaches specifically designed to treat co-morbid OUD and AUD. Here, the authors critically summarize OUD, AUD and opioid/alcohol co-use and their current pharmacotherapies for treatment. They also review the mechanisms of action of opioids and alcohol within the brain reward circuitry and discuss potential combined mechanisms of action and resulting neuroadaptations. Pharmacotherapies that aim to treat AUD or OUD that may be beneficial in the treatment of co-use are also highlighted. Preclinical models assessing alcohol and opioid co-use remain sparse. Lasting neuroadaptations in brain reward circuits caused by co-use of alcohol and opioids remains largely understudied. In order to fully understand the neurobiological underpinnings of alcohol and opioid co-use and develop efficacious pharmacotherapies, the preclinical field must expand its current experimental paradigms of 'single drug' use to encompass polysubstance use. Such studies will provide insights on the neural alterations induced by opioid and alcohol co-use, and may help develop novel pharmacotherapies for individuals with co-occurring alcohol and opioid use disorders.

Serotonin transporter gene (5-HTT) rs6354 polymorphism, job-related stress, and their interaction in burnout in healthcare workers in a Chinese hospital

OBJECTIVE

Many studies have reported that long-term exposure to job-related stress can lead to burnout, which may be influenced by genetic and environmental factors. Burnout correlates with depression. This study investigated whether one tag polymorphism rs6354 in 5-HTT gene modulated the influence of job-related stress on burnout in the medical professionals in a Chinese Han population, which to our best knowledge has not been explored.

METHODS

Seven hundred twelve subjects were recruited from a general hospital and measured for burnout symptoms using the Maslach Burnout Inventory (MBI), the stress using the House and Rizzo's Work Stress Scale, and the stressors using the Evers, Frese, and Cooper's Sources of Pressure Scale. The 5-HTT rs6354 polymorphism was genotyped in 376 subjects.

RESULTS

The majority of correlations between the work stress score or the six stressor scores and three burnout subscores were significant (all p < 0.05). There was no significant main effect of the 5-HTT rs6354 genotype on burnout symptoms; however, there was a statistically significant interaction between 5-HTT rs6354 and work stress on burnout (F = 5.08, df = 2, 369, p = 0.007). In the low stress group, G allele carriers had significantly higher burnout level than TT homozygote (F = 11.60, df = 1, 48, p < 0.001). On the contrary, in the high stress group, G allele carriers exhibited significantly lower burnout level compared to TT homozygote (F = 3.86, df = 1, 103, p = 0.025).

CONCLUSIONS

Our findings suggest that the 5-HTT rs6354 polymorphism may modulate the influence of job-related stress on burnout by adjusting serotonin transporter function and neurotransmission, showing that individuals with TT genotype displayed a greater susceptibility to both the detrimental effects of higher stress and the beneficial effects of lower stress compared to those with G allele, which supports the differential-susceptibility hypothesis.

Personality as an intermediate phenotype for genetic dissection of alcohol use disorder

Genetic and environmental interactive influences on predisposition to develop alcohol use disorder (AUD) account for the high heterogeneity among AUD patients and make research on the risk and resiliency factors complicated. Several attempts have been made to identify the genetic basis of AUD; however, only few genetic polymorphisms have consistently been associated with AUD. Intermediate phenotypes are expected to be in-between proxies of basic neuronal biological processes and nosological symptoms of AUD. Personality is likely to be a top candidate intermediate phenotype for the dissection of the genetic underpinnings of different subtypes of AUD. To date, 38 studies have investigated personality traits, commonly assessed by the Cloninger's Tridimensional Personality Questionnaire (TPQ) or Temperament and Character Inventory (TCI), in relation to polymorphisms of candidate genes of neurotransmitter systems in alcohol-dependent patients. Particular attention has been given to the functional polymorphism of the serotonin transporter gene (5-HTTLPR), however, leading to contradictory results, whereas results with polymorphisms in other candidate monoaminergic genes (e.g., tryptophan hydroxylase, serotonin receptors, monoamine oxidases, dopamine receptors and transporter) are sparse. Only one genome-wide association study has been performed so far and identified the ABLIM1 gene of relevance for novelty seeking, harm avoidance and reward dependence in alcohol-dependent patients. Studies investigating genetic factors together with personality could help to define more homogenous subgroups of AUD patients and facilitate treatment strategies. This review also urges the scientific community to combine genetic data with psychobiological and environmental data to further dissect the link between personality and AUD.

A systematic review and secondary data analysis of the interactions between the serotonin transporter 5-HTTLPR polymorphism and environmental and psychological factors in eating disorders

OBJECTIVES

To summarize and synthesize the growing gene x environment (GxE) research investigating the promoter region of the serotonin transporter gene (5-HTTLPR) in the eating disorders (ED) field, and overcome the common limitation of low sample size, by undertaking a systematic review followed by a secondary data meta-analysis of studies identified by the review.

METHOD

A systematic review of articles using PsycINFO, PubMed, and EMBASE was undertaken to identify studies investigating the interaction between 5-HTTLPR and an environmental or psychological factor, with an ED-related outcome variable. Seven studies were identified by the systematic review, with complete data sets of five community (n = 1750, 64.5% female) and two clinical (n = 426, 100% female) samples combined to perform four secondary-data analyses: 5-HTTLPR x Traumatic Life Events to predict ED status (n = 909), 5-HTTLPR x Sexual and Physical Abuse to predict bulimic symptoms (n = 1097), 5-HTTLPR x Depression to predict bulimic symptoms (n = 1256), and 5-HTTLPR x Impulsiveness to predict disordered eating (n = 1149).

RESULTS

Under a multiplicative model, the low function (s) allele of 5-HTTLPR interacted with traumatic life events and experiencing both sexual and physical abuse (but not only one) to predict increased likelihood of an ED and bulimic symptoms, respectively. However, under an additive model there was also an interaction between sexual and physical abuse considered independently and 5-HTTLPR, and no interaction with traumatic life events. No other GxE interactions were significant.

CONCLUSION

Early promising results should be followed-up with continued cross-institutional collaboration in order to achieve the large sample sizes necessary for genetic research.

Alcohol Dependence and Genetic Variability in the Serotonin Pathway among Currently and Formerly Alcohol-Dependent Males

BACKGROUND

Genes involved in the serotonin pathway may determine the susceptibility to alcohol dependence and its severity. The present study explored whether specific polymorphisms in the serotonin pathway could be associated with alcohol dependence or alcohol-related psychopathological symptoms.

METHODS

The cohort comprised 101 currently and 100 formerly alcohol-dependent males, as well as 97 male healthy blood donors. The following questionnaires were employed: the Alcohol Use Disorders Identification Test, the Zung Depression and Anxiety Scale, the Brief Social Phobia Scale, the Yale-Brown Obsessive Compulsive Scale and Obsessive Compulsive Drinking Scale, and the Buss-Durkee Hostility Inventory. Subjects were genotyped for bi- and triallelic SLC6A4 5-HTTLPR,HTR1A rs6295, and HTR1B rs13212041.

RESULTS

Statistical differences in bi- and triallelic SLC6A4 5-HTTLPR genotype distribution were observed between the 3 groups investigated (p = 0.008 and p = 0.023, respectively); however, no gene-dose effect was observed. The severity of the alcohol problems was higher in currently alcohol-dependent subjects with the 5-HTTLPR LL (p = 0.039) and L′L′ genotypes (p = 0.027). Formerly dependent subjects with the 5-HTTLPR S′S′ genotype showed more social anxiety, depressive, and anxiety traits (p = 0.009, p = 0.006, and p = 0.036, respectively). Healthy controls with the 5-HTTLPR SS genotype showed more traits of social anxiety (p = 0.020).

CONCLUSIONS

Our findings suggest that bi- and triallelic SLC6A4 5-HTTLPR has some effects on the severity of alcohol dependence. Triallelic 5-HTTLPR was associated with social anxiety, anxiety, and depressive traits in alcohol-dependent subjects.

Association between serotonin transporter gene polymorphisms and heroin dependence: a meta-analytic study

BACKGROUND

Studies have examined the association between heroin dependence and serotonin transporter gene polymorphisms but yielded inconsistent results. The purpose of current study is to determine the overall effect of these polymorphisms on the risk for heroin dependence through a meta-analytic method.

METHODS

A meta-analysis was conducted to examine the association of heroin dependence with two common polymorphisms of serotonin transporter gene, in the promoter (5-hydroxytryptamine transporter-linked promotor region [5-httlpr]) and intron 2 (a various number tandem repeat in serotonin transporter intron 2 [STin2]). Data from studies with 5-httlpr (6 studies) and STin2 (8 studies) were synthesized by random effects model.

RESULTS

In the analysis, heroin dependence was found to be significantly associated with the S allele of 5-httlpr (odds ratio [OR] =1.22, 95% confidence interval [CI] =1.08-1.41, P=0.002). The association between the S allele of 5-httlpr and heroin dependence was significant in Caucasian subjects (OR =1.37, 95% CI =1.12-1.68, P=0.003), but not in non-Caucasian subjects. On the other hand, no association with STin2 polymorphism was found (OR =1.14, 95% CI =0.91-1.42, P=0.242).

CONCLUSION

The results suggest an ethnic-specific effect of the 5-httlpr polymorphism on the risk for heroin dependence, but the influence of the genetic variance in the patients with comorbidities or intermediate phenotypes of heroin dependence needs to be further examined.

Predictors of heroin relapse: Personality traits, impulsivity, COMT gene Val158met polymorphism in a 5-year prospective study in Shanghai, China

Relapse is a typical feature of heroin addiction and rooted in genetic and psychological determinants. The aim of this study was to evaluate the effect of personality traits, impulsivity, and COMT gene polymorphism (rs4680) on relapse to heroin use during 5-year follow up. 564 heroin dependent patients were enrolled in compulsory drug rehabilitation center. 12 months prior to their release, personality traits were measured by BIS-11 (Barratt Impulsiveness Scale-11) and Temperament and Character Inventory (TCI). The COMT gene rs4680 polymorphism was genotyped using a DNA sequence detection system. The heroin use status was evaluated for 5 years after discharged. Among the 564 heroin-dependent patients, 500 were followed for 5 years after discharge and 53.0% (n = 265) were considered as relapsed to heroin use according to a strict monitor system. Univariate analysis showed that age, having ever been in methadone maintenance treatment (MMT), the total scores and non-planning scores of BIS-11, and the COMT rs4680 gene variants were different between relapse and abstinent groups. Logistic regression analysis showed higher BIS total score, having ever been in MMT and younger first heroin use age are the predictors of relapse to heroin use during 5 years follow-up, and the COMT rs4680 gene had an interaction with BIS scores. Our findings indicated that the impulsive personality traits, methadone use history, and onset age could predict relapse in heroin-dependent patients during 5 year's follow up. The COMT gene showed a moderational effect in part the relationship of impulsivity with heroin relapse.

Endogenous opiates and behavior: 2013

This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.

Hatching the behavioral addiction egg: Reward Deficiency Solution System (RDSS)™ as a function of dopaminergic neurogenetics and brain functional connectivity linking all addictions under a common rubric

BACKGROUND

Following the first association between the dopamine D2 receptor gene polymorphism and severe alcoholism, there has been an explosion of research reports in the psychiatric and behavioral addiction literature and neurogenetics. With this increased knowledge, the field has been rife with controversy. Moreover, with the advent of Whole Genome-Wide Studies (GWAS) and Whole Exome Sequencing (WES), along with Functional Genome Convergence, the multiple-candidate gene approach still has merit and is considered by many as the most prudent approach. However, it is the combination of these two approaches that will ultimately define real, genetic allelic relationships, in terms of both risk and etiology. Since 1996, our laboratory has coined the umbrella term Reward Deficiency Syndrome (RDS) to explain the common neurochemical and genetic mechanisms involved with both substance and non-substance, addictive behaviors.

METHODS

This is a selective review of peer-reviewed papers primary listed in Pubmed and Medline.

RESULTS

A review of the available evidence indicates the importance of dopaminergic pathways and resting-state, functional connectivity of brain reward circuits.

DISCUSSION

Importantly, the proposal is that the real phenotype is RDS and impairments in the brain's reward cascade, either genetically or environmentally (epigenetically) induced, influence both substance and non-substance, addictive behaviors. Understanding shared common mechanisms will ultimately lead to better diagnosis, treatment and prevention of relapse. While, at this juncture, we cannot as yet state that we have "hatched the behavioral addiction egg", we are beginning to ask the correct questions and through an intense global effort will hopefully find a way of "redeeming joy" and permitting homo sapiens live a life, free of addiction and pain.

DRD2/CHRNA5 interaction on prefrontal biology and physiology during working memory

BACKGROUND

Prefrontal behavior and activity in humans are heritable. Studies in animals demonstrate an interaction between dopamine D2 receptors and nicotinic acetylcholine receptors on prefrontal behavior but evidence in humans is weak. Therefore, we hypothesize that genetic variation regulating dopamine D2 and nicotinic acetylcholine receptor signaling impact prefrontal cortex activity and related cognition. To test this hypothesis in humans, we explored the interaction between functional genetic variants in the D2 receptor gene (DRD2, rs1076560) and in the nicotinic receptor α5 gene (CHRNA5, rs16969968) on both dorsolateral prefrontal cortex mediated behavior and physiology during working memory and on prefrontal gray matter volume.

METHODS

A large sample of healthy subjects was compared for genotypic differences for DRD2 rs1076560 (G>T) and CHNRA5 rs16969968 (G>A) on prefrontal phenotypes, including cognitive performance at the N-Back task, prefrontal physiology with BOLD fMRI during performance of the 2-Back working memory task, and prefrontal morphometry with structural MRI.

RESULTS

We found that DRD2 rs1076560 and CHNRA5 rs16969968 interact to modulate cognitive function, prefrontal physiology during working memory, and prefrontal gray matter volume. More specifically, CHRNA5-AA/DRD2-GT subjects had greater behavioral performance, more efficient prefrontal cortex activity at 2Back working memory task, and greater prefrontal gray matter volume than the other genotype groups.

CONCLUSIONS

The present data extend previous studies in animals and enhance our understanding of dopamine and acetylcholine signaling in the human prefrontal cortex, demonstrating interactions elicited by working memory that are modulated by genetic variants in DRD2 and CHRNA5.

A retrospective analysis focusing on a group of patients with dual diagnosis treated by both mental health and substance use services

OBJECTIVE

To highlight which demographic, familial, premorbid, clinical, therapeutic, rehabilitative, and assistance factors were related to dual diagnosis, which, in psychiatry, means the co-occurrence of both mental disorder and substance use in the same patient.

METHODS

Our sample (N=145) was chosen from all outpatients with a dual diagnosis treated from January 1, 2012 to July 31, 2012 by both the Mental Health Service and the Substance Use Service of Modena and Castelfranco Emilia, Italy. Patients who dropped out during the study period were excluded. Demographic data and variables related to familial and premorbid history, clinical course, rehabilitative programs, social support and nursing care, and outcome complications were collected. The patients' clinical and functioning conditions during the study period were evaluated.

RESULTS

Our patients were mostly men suffering from a cluster B personality disorder. Substance use was significantly more likely to precede psychiatric disease (P<0.001), and 60% of the sample presented a positive familial history for psychiatric or addiction disease or premorbid traumatic factors. The onset age of substance use was related to the period of psychiatric treatment follow-up (P<0.001) and the time spent in rehabilitative facilities (P<0.05), which, in turn, was correlated with personality disorder diagnosis (P<0.05). Complications, which presented in 67% of patients, were related to the high number of psychiatric hospitalizations (P<0.05) and professionals involved in each patient's treatment (P<0.05). Males more frequently presented familial, health, and social complications, whereas females more frequently presented self-threatening behavior (P<0.005).

CONCLUSION

It was concluded that the course of dual diagnosis may be chronic, severe, and disabling, requiring many long-term therapeutic and rehabilitative programs to manage various disabilities.