Sex, drugs, and rock 'n' roll: hypothesizing common mesolimbic activation as a function of reward gene polymorphisms

Optimal sexual frequency may exist and help mitigate depression odds in young and middle-aged U.S. citizens: A cross-sectional study

BACKGROUND

While sexual activity is known to benefit physical health, its connection to psychological well-being is less studied. We hypothesized that lower self-reported sexual frequency would be independently associated with higher odds of depression, as assessed by the Patient Health Questionnaire-9 (PHQ-9).

METHODS

We included 15,794 U.S. adults aged 20-59, reporting sexual frequency and complete PHQ-9 scores, from the National Health and Nutrition Examination Survey (2005-2016). Logistic regression models evaluated the independent association between sexual frequency and depression, while restricted cubic spline models explored potential non-linear associations.

RESULTS

The analysis revealed a significant negative association between sexual frequency and the odds of depression. Compared to those engaging in sexual activity less than once per month, participants reporting sexual activity once per month but less than once per week (OR: 0.58; 95 % CI: 0.48-0.70) and at least once per week (OR: 0.6; 95 % CI: 0.51-0.69) had lower odds of depressive symptoms. The restricted cubic spline model indicated a saturation effect (P for nonlinearity = 0.002), suggesting an optimal sexual frequency of 52 to 103 times per year (1-2 times per week) to reduce depression odds.

CONCLUSION

We revealed a significant negative association between self-reported sexual frequency and the odds of depression. A sexual frequency of 1-2 times per week showed the greatest protective effects on psychological well-being and may serve as a reference standard for mental health evaluation and monitoring during depression treatment. Further research is needed to determine directionality, causality, and potential modifiers of this association.

Genomic factors associated with substance use disorder relapse: A critical review

Several genetic and epigenetic factors contribute to the elevated substance use disorder (SUD) relapse vulnerability, yet a comprehensive investigation into these factors is lacking. This review aims to delve into current literature to highlight key genomic factors associated with SUD relapse. Focusing on genetic predisposition and epigenetic modifications the review synthesized research findings of several genetic polymorphisms, histone modifications and DNA methylation patterns contributing to the initiation of SUD and the elevated relapse susceptibility. Notably, specific gene polymorphisms, such as Dopamine Receptor D2 gene (DRD2), Gamma-Aminobutyric Acid Receptor Alpha gene (GABRA2), Catechol-O-methyltransferase (COMT) gene, Dopamine Transporter (DAT1) gene and others were identified to be connected to various patterns of SUD relapse. Furthermore, SUD initiation and relapse has been shown to be influenced by epigenetics. Specifically, CpG hypermethylation has been associated with severe alcohol use disorder in the 5' untranslated region of the Bladder Cancer Associated Protein gene (BLCAP) and the upstream region of the Active BCR Related gene (ABR). Co-users of cannabis and tobacco showed notable variations in CpG site methylation, especially at the Aryl Hydrocarbon Receptor Repressor (AHRR), and factor II receptor-like 3 gene sites (F2RL3). In conclusion, there is good evidence of certain associations between genomic factors and relapse to SUD. However, further research is needed to ascertain causality effects of these factors and develop novel interventions for effective treatment and relapse prevention.

Solving the Global Opioid Crisis: Incorporating Genetic Addiction Risk Assessment with Personalized Dopaminergic Homeostatic Therapy and Awareness Integration Therapy

Objectives

The opioid crisis in the last few decades has mounted to a global level, impacting all areas of socioeconomic, demographic, geographic, and cultural boundaries. Traditional treatments have not been deemed to show the degree of efficacy necessary to address the crisis. The authors of this review paper have set forth an unprecedented and in-depth look into multi-factorial determinants that have contributed to the opioid crisis becoming global and multi-faceted.

Methods

For this narrative review/opinion article, we searched PsychINFO, PubMed, Google Scholar, and Web of Science databases to identify relevant articles on topics including the "opioid crisis," "opioid mechanisms," "genetics and epigenetics," "neuropharmacology," and "clinical aspects of opioid treatment and prevention." Since this was not a systematic review the articles selected could represent unitential bias.

Results

Despite some success achieved through Opioid Substitution Therapy (OST) in harm reduction, the annual mortality toll in the US alone surpasses 106,699 individuals, a figure expected to climb to 165,000 by 2025. Data from the Substance Abuse and Mental Health Services Administration's (SAMHSA) National Survey on Drug Abuse and Health (NSDUH) reveals that approximately 21.4% of individuals in the US engaged in illicit drug use in 2020, with 40.3 million individuals aged 12 or older experiencing a Substance Use Disorder (SUD). Provisional figures from the Centers for Disease Control and Prevention (CDC) indicate a troubling 15% increase in overdose deaths in 2021, rising from 93,655 in 2020 to 107,622, with opioids accounting for roughly 80,816 of these deaths.

Conclusions

We advocate reevaluating the "standard of care" and shifting towards inducing dopamine homeostasis by manipulating key neurotransmitter systems within the brain's reward cascade. We propose a paradigm shift towards a novel "standard of care" that begins with incorporating Genetic Addiction Risk Severity (GARS) testing to assess pre-addiction risk and vulnerability to opioid-induced addiction; emphasis should be placed on inducing dopamine homeostasis through safe and non-addictive alternatives like KB220, and comprehensive treatment approaches that address psychological, spiritual, and societal aspects of addiction through Awareness Integration Therapy (AIT).

Dynamic regulation of the extracellular matrix in reward memory processes: a question of time

Substance use disorders are a global health problem with increasing prevalence resulting in significant socioeconomic burden and increased mortality. Converging lines of evidence point to a critical role of brain extracellular matrix (ECM) molecules in the pathophysiology of substance use disorders. An increasing number of preclinical studies highlight the ECM as a promising target for development of novel cessation pharmacotherapies. The brain ECM is dynamically regulated during learning and memory processes, thus the time course of ECM alterations in substance use disorders is a critical factor that may impact interpretation of the current studies and development of pharmacological therapies. This review highlights the evidence for the involvement of ECM molecules in reward learning, including drug reward and natural reward such as food, as well as evidence regarding the pathophysiological state of the brain's ECM in substance use disorders and metabolic disorders. We focus on the information regarding time-course and substance specific changes in ECM molecules and how this information can be leveraged for the development of therapeutic strategies.

Striatal dopamine D2-like receptors availability in obesity and its modulation by bariatric surgery: a systematic review and meta-analysis

There is significant evidence linking a 'reward deficiency syndrome' (RDS), comprising decreased availability of striatal dopamine D2-like receptors (DD2lR) and addiction-like behaviors underlying substance use disorders and obesity. Regarding obesity, a systematic review of the literature with a meta-analysis of such data is lacking. Following a systematic review of the literature, we performed random-effects meta-analyses to determine group differences in case-control studies comparing DD2lR between individuals with obesity and non-obese controls and prospective studies of pre- to post-bariatric surgery DD2lR changes. Cohen's d was used to measure effect size. Additionally, we explored factors potentially associated with group differences in DD2lR availability, such as obesity severity, using univariate meta-regression. In a meta-analysis including positron emission tomography (PET) and single-photon emission computed tomography (SPECT) studies, striatal DD2lR availability did not significantly differ between obesity and controls. However, in studies comprising patients with class III obesity or higher, group differences were significant, favoring lower DD2lR availability in the obesity group. This effect of obesity severity was corroborated by meta-regressions showing inverse associations between the body mass index (BMI) of the obesity group and DD2lR availability. Post-bariatric changes in DD2lR availability were not found, although a limited number of studies were included in this meta-analysis. These results support lower DD2lR in higher classes of obesity which is a more targeted population to explore unanswered questions regarding the RDS.

Stress, psychiatric disease, and obesity: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

Previous Obesity Medicine Association (OMA) Clinical Practice Statements (CPS) included topics such as behavior modification, motivational interviewing, and eating disorders, as well as the effect of concomitant medications on weight gain/reduction (i.e., including psychiatric medications). This OMA CPS provides clinicians a more focused overview of stress and psychiatric disease as they relate to obesity.

Methods

The scientific support for this CPS is based upon published citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

Topics in this CPS include the relationship between psychological stress and obesity, including both acute and chronic stress. Additionally, this CPS describes the neurobiological pathways regarding stress and addiction-like eating behavior and explores the relationship between psychiatric disease and obesity, with an overview of psychiatric medications and their potential effects on weight gain and weight reduction.

Conclusions

This Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) on stress and psychiatric disease is one of a series of OMA CPSs designed to assist clinicians in the care of patients with the disease of obesity. Knowledge of stress, addiction-like eating behavior, psychiatric disease, and effects of psychiatric medications on body weight may improve the care obesity medicine clinicians provide to their patients with obesity.

Should Reward Deficiency Syndrome (RDS) Be Considered an Umbrella Disorder for Mental Illness and Associated Genetic and Epigenetic Induced Dysregulation of Brain Reward Circuitry?

Reward Deficiency Syndrome (RDS) is defined as a breakdown of reward neurotransmission that results in a wide range of addictive, compulsive, and impulsive behaviors. RDS is caused by a combination of environmental (epigenetic) influences and DNA-based (genetic) neurotransmission deficits that interfere with the normal satisfaction of human physiological drives (i.e., food, water, and sex). An essential feature of RDS is the lack of integration between perception, cognition, and emotions that occurs because of (1) significant dopaminergic surges in motivation, reward, and learning centers causing neuroplasticity in the striato-thalamic-frontal cortical loop; (2) hypo-functionality of the excitatory glutamatergic afferents from the amygdala-hippocampus complex. A large volume of literature regarding the known neurogenetic and psychological underpinnings of RDS has revealed a significant risk of dopaminergic gene polymorphic allele overlap between cohorts of depression and subsets of schizophrenia. The suggestion is that instead of alcohol, opioids, gambling disorders, etc. being endophenotypes, the true phenotype is RDS. Additionally, reward deficiency can result from depleted or hereditary hypodopaminergia, which can manifest as a variety of personality traits and mental/medical disorders that have been linked to genetic studies with dopamine-depleting alleles. The carrying of known DNA antecedents, including epigenetic insults, results in a life-long vulnerability to RDS conditions and addictive behaviors. Epigenetic repair of hypodopaminergia, the causative basis of addictive behaviors, may involve precision DNA-guided therapy achieved by combining the Genetic Addiction Risk Severity (GARS) test with a researched neutraceutical having a number of variant names, including KB220Z. This nutraceutical formulation with pro-dopamine regulatory capabilities has been studied and published in peer-reviewed journals, mostly from our laboratory. Finally, it is our opinion that RDS should be given an ICD code and deserves to be included in the DSM-VI because while the DSM features symptomology, it is equally important to feature etiological roots as portrayed in the RDS model.

Historical and Modern Evidence for the Role of Reward Circuitry in Emergence

Increasing evidence supports a role for brain reward circuitry in modulating arousal along with emergence from anesthesia. Emergence remains an important frontier for investigation, since no drug exists in clinical practice to initiate rapid and smooth emergence. This review discusses clinical and preclinical evidence indicating a role for two brain regions classically considered integral components of the mesolimbic brain reward circuitry, the ventral tegmental area and the nucleus accumbens, in emergence from propofol and volatile anesthesia. Then there is a description of modern systems neuroscience approaches to neural circuit investigations that will help span the large gap between preclinical and clinical investigation with the shared aim of developing therapies to promote rapid emergence without agitation or delirium. This article proposes that neuroscientists include models of whole-brain network activity in future studies to inform the translational value of preclinical investigations and foster productive dialogues with clinician anesthesiologists.

“Sax for Sex”: A Brief Narrative Review Exploring the Music-Sex Connect

Context:

The assertion that music has an impact on sexual performance is a popular one. However, music is seldom used in clinical settings for enhancement of sexual problems and little is known regarding its scientific proof.

Aim:

To explore available literature on: the interplay between sex and music in the human evolution; brain basis for music and sex; and studies using music to therapeutically enhance sexual performance.

Conclusions:

Evidence suggests an evolutionary basis for the relationship between music and sex. There is converging neurobiological understanding that posits both music and sex to have common brain substrates—the reward pathway, diencephalic structures, limbic system, and prefrontal cortex. Psychological mechanisms hypothesized for a positive role of music in enhancing the act of sex need systematic evaluation. The empirical evidence for the use of music as an adjunct strategy in the treatment of sexual dysfunctions, though positive and encouraging, is still sparse.

The interaction between sexual reward/ deprivation and the acquisition, extinction and reinstatement of morphine-seeking behavior

Natural rewards and abused drugs affect the function of the common brain's reward system. Interaction between social and drug rewards can change the vulnerability to development of drug addiction. Here, we investigate the effects of sexual experience and sex deprivation on the acquisition, maintenance, and drug prime-induced reinstatement of morphine-seeking behavior in male mice using conditioned place preference (CPP). CPP induced with morphine (3, 5, 7 mg/kg, s.c. for 3 days) lasted for 10 days after cessation of morphine treatment and priming dose of morphine (2 mg/kg, s.c.) reinstated the extinguished CPP. In the post-test phase, sexually experienced animals showed a lower preference for morphine compared to sex-deprived males. In the extinction phase, sex deprivation shortened maintenance time compared to control animals. The preference for morphine in sexually experienced animals did not diminish by the seventeenth extinction day. In both groups, the priming injection of morphine after the extinction period could reinstate the extinguished morphine-induced CPP. Together, these data showed the interaction between sex and drug reward and that sexual behavior -a natural rewarding stimulus- can prolong, whereas sex deprivation can block the maintenance of morphine-seeking behaviors. Sexual experience may induce functional and morphological alterations in brain reward areas particularly the mesolimbic system similar to repeated exposure to abused drugs which can affect morphine-seeking behaviors.

Neurological correlates of brain reward circuitry linked to opioid use disorder (OUD): Do homo sapiens acquire or have a reward deficiency syndrome?

The extant literature confirms that an array of polymorphic genes related to- neurotransmitters and second messengers govern the net release of dopamine in the Nucleus Accumbens (NAc) in the mesolimbic region of the brain. They are linked predominantly to motivation, anti-stress, incentive salience (wanting), and wellbeing. Notably, in 2000 the Nobel Prize was awarded to Carlsson, Greengard, and Kandel for their work on the molecular and cellular function of dopaminergic activity at neurons. This historical psychopharmacological work involved neurotransmission of serotonin, endorphins, glutamate, and dopamine, and the seminal work of Blum, Gold, Volkow, Nestler, and others related to neurotransmitter function and related behaviors. Currently, Americans are facing their second and worst opioid epidemic, prescribed opioids, and easy access drive this epidemic of overdoses, and opioid use disorders (OUDs). Presently the clinical consensus is to treat OUD, as if it were an opioid deficiency syndrome, with long-term to life-long opioid substitution therapy. Opioid agonist administration is seen as necessary to replace missing opioids, treat OUD, and prevent overdoses, like insulin is used to treat diabetes. Treatment of OUD and addiction, in general, is similar to the endocrinopathy conceptualization in that it views opioid agonist MATs as an essential core to therapy. Is this approach logical? Other than as harm reduction, is using opioids to treat OUD therapeutic or harmful in the long term? This historical Trieste provides a molecular framework to understand the current underpinnings of endorphinergic/dopaminergic mechanisms related to opioid deficiency syndrome and generalized reward processing depletion. WC 249.

Trends in Sexual Activity and Associations With All-Cause and Cause-Specific Mortality Among US Adults

BACKGROUND

Sexual activity can be referred to as a health behavior and may also act as an indicator of health status.

AIM

To evaluate temporal trends in sexual activity and to examine associations of sexual activity with all-cause and cause-specific mortality risk.

METHODS

We examined the trends and prevalence of sexual activity and association of sexual activity with all-cause and cause-specific mortality in a nationally representative sample using data from the US National Health and Nutrition Examination Survey from 2005 to 2016 and the National Health and Nutrition Examination Survey 2005-2014 Linked Mortality File (through December 31, 2015).

OUTCOMES

All-cause, cardiovascular disease, and cancer mortality.

RESULTS

A total of 15,269 US adults (mean age, 39.1 years [standard error, 0.18 years]) were included in the trend analysis. In the 2015-2016 cycle, while 71.7% (95% CI, 67.7-75.7%) US adults aged 20-59 years engaged in sexual activity ≥ 12 times/year (monthly), only 36.1% (95% CI, 31.6-40.7%) of them engaged in sexual activity ≥ 52 times/year (weekly). Since the 2005-2006 cycle, the estimated prevalence of sexual activity, ≥52 times/year and ≥12 times/year, were both stable over time among overall and each age group (all P for trend >0.1). During a median follow-up of 5.7 years (range, 1-11 years) and 71,960 person-years of observation, among 12,598 participants with eligible information on mortality status, 228 deaths occurred, including 29 associated with cardiovascular disease and 62 associated with cancer. Overall, participants with higher sexual activity frequency were at a lower risk of all-cause death in a dose-response manner (P for trend = 0.020) during the follow-up period. In addition, the multivariable-adjusted hazard ratios for all-cause mortality, CVD mortality, cancer mortality, and other cause mortality among participants who had sex ≥52 times/year compared with those having sex 0-1 time/year were 0.51 (95% CI, 0.34 to 0.76), 0.79 (95% CI, 0.19 to 3.21), 0.31 (95% CI, 0.11 to 0.84), and 0.52 (95% CI, 0.28 to 0.96), respectively.

CLINICAL IMPLICATIONS

Sexual activity appears to be a health indicator of all-cause and cancer mortality in US middle-aged adults.

STRENGTHS & LIMITATIONS

Clear strengths of the present study include the large representative sample of the noninstitutionalized US population as well as the identification of precise estimates in relation to sexual activity and mortality. However, because of the observational nature of the study design, causality could not be determined.

CONCLUSIONS

Sexual activity was found to be associated with a lower risk of mortality from all cause and cancer. Cao C, Yang L, Xu T, et al. Trends in Sexual Activity and Associations With All-Cause and Cause-Specific Mortality Among US Adults. J Sex Med 2020;17:1903-1913.

Are sweetened drinks a gateway to alcohol, opiate and stimulant addiction? Summary of evidence and therapeutic strategies

1. Drinks sweetened with both sugar and artificial additives lead to dopamine release at the nucleus accumbens (NAc) in rat models; the basis of experiences of pleasure in humans, resulting in impulsive binging behaviour at times. 2. Evidence from rat models show cross sensitisation between sweetened drinks, alcohol, opiates and stimulants. Therefore, it could be hypothesised that sweetened drinks could be a gateway to multiple substance abuse among humans via 'alcopops'. 3. Identification of an allelic variant of the cyclic adenosine monophosphate responsive element modulator gene (CREM), linking impulsivity and multiple substance abuse, opens up prospects of mass screening to advice on harm reduction. 4. Furthermore, therapies involving cannabinoid receptor antagonists and transcranial brain stimulation are being currently investigated; of benefit to limit binge use of sweetened drinks.

[Sex addiction: losing its taboo]

Sex addiction or dependency is a complex and debilitating pathology characterised by a disproportionate preoccupation with sex or sexual activity. The aim of scientific research carried out into this disorder is both nosographic, to establish which subtype of mental disorder it belongs to, and physiopathological, to explain its origin and develop potential therapies. A state of the science on sexual dependency is charted, in the world of psychiatry, based on its very first mention to the present day.

Effects of long-term high-fat food or methamphetamine intake and serotonin 2C receptors on reversal learning in female rhesus macaques

Perseverative behavior has been highly implicated in addiction. Activation of serotonin 2C receptors (5-HT_2CRs) attenuates cocaine and high caloric food intake, but whether a 5-HT_2CR agonist can reduce high caloric diet (HCD) or methamphetamine (METH) intake and response perseveration remains unknown. Clarifying the role of 5-HT_2CRs in these behaviors will improve knowledge of neurochemical processes that regulate flexible decision-making and whether improvements in decision-making are accompanied by decreases in HCD or METH intake. This study evaluated the effects of long-term HCD and METH intake on reversal learning in female rhesus monkeys. The effects of the 5-HT_2CR agonist WAY163909 on reversal learning before and after extended HCD or METH intake, and on food intake, was also tested. Moreover, we examined whether the 5-HT_2CR is necessary for the effects of WAY163909. WAY163909 was given prior to reversal learning at baseline and after extended HCD or METH intake, and prior to measures of food intake. Extended intake of METH or the HCD increased perseverative errors during reversal. WAY163909 increased correct responses and decreased perseverative errors, both before and after extended HCD or METH intake. Similarly, WAY163909 decreased consumption of a HCD, but not a low caloric diet. The effects of WAY163909 on all these measures were blocked by co-administration with a 5-HT_2CR antagonist. These data indicate that long-term HCD or METH intake disrupts flexible decision-making. Further, the results suggest that reductions in food intake produced by WAY163909 are associated with parallel improvements in decision-making strategies, underscoring the role of the 5-HT_2CR for these behavioral effects.

Online Porn Addiction: What We Know and What We Don't-A Systematic Review

In the last few years, there has been a wave of articles related to behavioral addictions; some of them have a focus on online pornography addiction. However, despite all efforts, we are still unable to profile when engaging in this behavior becomes pathological. Common problems include: sample bias, the search for diagnostic instrumentals, opposing approximations to the matter, and the fact that this entity may be encompassed inside a greater pathology (i.e., sex addiction) that may present itself with very diverse symptomatology. Behavioral addictions form a largely unexplored field of study, and usually exhibit a problematic consumption model: loss of control, impairment, and risky use. Hypersexual disorder fits this model and may be composed of several sexual behaviors, like problematic use of online pornography (POPU). Online pornography use is on the rise, with a potential for addiction considering the "triple A" influence (accessibility, affordability, anonymity). This problematic use might have adverse effects in sexual development and sexual functioning, especially among the young population. We aim to gather existing knowledge on problematic online pornography use as a pathological entity. Here we try to summarize what we know about this entity and outline some areas worthy of further research.

Effects of Sexual Arousal and Alcohol Cues on Acute Motivation for Alcohol

Reward-related stimuli can induce motivation to obtain rewards both within and across domains. We tested within- and cross-domain effects of environmental context (mock bar vs. laboratory) and sexually arousing stimuli (pornography vs. nature film) on acute motivation for alcohol as measured by a state-based alcohol purchase task in 109 male and female college students. Our results showed significant effects of both sexual arousal and environmental context on acute motivation for alcohol. A limited subsample analysis (N = 84) revealed significant effects of both sexual arousal and environmental context conditions on elasticity. Consistent with hypotheses, the presence of either sex- or alcohol-related cues increased acute motivation for alcohol and decreased sensitivity to costs of drinking. Furthermore, there was a significant video × laboratory condition interaction in the elasticity analysis. Our findings suggest that both sexually arousing stimuli and incidental environmental alcohol cues may significantly increase the effort one will expend to consume alcohol and thus the potential for risky drinking behavior. We believe this is the first experiment to use demand curves to present evidence of cross-domain effects of sexually arousing stimuli on acute motivation for alcohol.

Our evolved unique pleasure circuit makes humans different from apes: Reconsideration of data derived from animal studies

The brain regions tied to pleasure can be triggered by engaging in sex, eating tasty food, watching a movie, accomplishments at school and athletics, consuming drugs, and noble efforts to help the community, the country, and the world. It is noteworthy that research suggests that the latter type of satisfaction, supporting the community, may result in the most substantial positive effects on our immune system. However, these pathways for these effects are not understood. Berridge and Kringelbach have suggested that pleasure is mediated by well-developed mesocorticolimbic circuitry and serves adaptive functions. In affective disorders, anhedonia (lack of pleasure) or dysphoria (negative affect) can result from a breakdown of that hedonic system. Most importantly, human neuroimaging investigations indicate that surprisingly similar circuitry is activated by quite diverse pleasures, suggesting a common neural pathway shared by all rewarding stimuli and behaviors.

Over many years the controversy of dopamine involvement in pleasure/reward has led to confusion in terms, such as trying to separate motivation from pure pleasure (i.e., wanting versus liking). We take the position that animal studies cannot provide real clinical information that is described by self-reports in humans. On November 23^rd, 2017, evidence for our concerns was revealed. A brain system involved in everything from addiction to autism appears to have evolved differently in humans than in apes, as reported by a large research team in the journal Science. To reiterate, the new findings by Sousa et al., also suggest the importance of not over-relying on rodent and even non-human primate studies. Extrapolations, when it comes to the concept of pleasure, dopamine, and reinforcement, are not supported by these data. Human experience and study are now much more critical and important. Extrapolations from non-humans to humans may be more fiction than fact. While this statement is bold it should not at all suggest that animal date is unimportant, that is not the case. It is extremely valuable in many aspects and we must encourage the development of animal models for disease. However, we must be cautious in our interpretation of results without leaping to conclusions that may be explained by follow-up human experiments and subsequent data.

We are further proposing that in terms of overcoming a never –ending battle related to the current drug epidemic, the scientific community should realize that disturbing dopamine homeostasis by taking drugs or having a system compromised by genes or other epigenetic experiences, should be treated by alternative therapeutic modalities, expressed in this article as a realistic key goal. Application of genetic addiction risk (GARS™) testing and pro-dopamine regulation (KB220) should be considered along with other promising technologies including cognitive behavioral therapy, mind fullness, brain spotting and trauma therapy. Basic scientists have worked very hard to dis-entangle pleasure from incentive salience and learning signals in brain reward circuitry, but this work may be limited to animal models and rodents. A different consideration regarding the human reward systems is required.

Sexual addiction in drug addicts: The impact of drug of choice and poly-addiction

Objective:

To compare the risk of comorbid sexual addiction in a sample of individuals with a diagnosis of substance dependence, stratifying the sample by drug of choice as well as by mono versus polysubstance addiction.

Method:

All data were collected at Santa Casa de São Paulo, Brazil. The study sample comprised all alcohol or drug dependents admitted to the Addiction Treatment Unit between November 2013 and August 2014. A generalized linear model with a binomial distribution was performed to compare the odds of having a Sexual Addiction Screening Test (SAST) score greater than 6 points in the subgroups analyzed.

Results:

A total of 133 participants were included in our analysis, all reporting cocaine/crack and/or alcohol as drug of choice. Polysubstance addicts had a significant higher risk of a positive screening for sexual addiction compared to monosubstance addicts, age-sex adjusted odds ratios of sexual addiction being respectively 2.72 (95CI 1.1-6.71) and 0.37 (95CI 0.15-0.91). The odds of a SAST score greater than 6 was not statistically different between the cocaine/crack and alcohol groups, respectively 0.38 (95CI 0.14-1.02) and 2.67 (95CI 0.98-7.25). We found a significant relation between stronger drug addiction and greater levels of sexual addiction in the cocaine/crack group (p=0.0012), but not in the alcohol group.

Conclusion:

Our study reinforces the importance of assessing sexual behavior of drug addicts in clinical practice, especially considering users of multiple substances or with severe dependence.

The effect of 8-OH-DPAT and dapoxetine on gene expression in the brain of male rats during ejaculation

The 5-HT_1A receptor agonist 8-hydroxy-2-[di-n-propylamino] tetralin (8-OH-DPAT) promotes ejaculation of male rats, whereas dapoxetine delays this process. However, the gene expression profile of the brain at ejaculation following administrationof these two compounds has not been fully elucidated. In the present study, a transcriptomic BodyMap was generated by conducting mRNA-Seq on brain samples of male Sprague–Dawley rats. The study included four groups: pre-copulatory control (CK) group, ejaculation (EJ) group, 0.5 mg/kg 8-OH-DPAT-ejaculation group (DPAT), and 60 mg/kg dapoxetine-ejaculation (DAP) group. The resulting analysis generated an average of approximately 47 million sequence reads. Significant differences in the gene expression profiles of the aforementioned groups were observed in the EJ (257 genes), DPAT (349 genes) and the DAP (207 genes) compared with the control rats. The results indicate that the expression of Drd1 and Slc6a3 was significantly different after treatment with 8-OH-DPAT, whereas the expression of Drd4 was significantly different after treatment with dapoxetine. Other genes, such as Wnt9b, Cdkn1a and Fosb, exhibited significant differences in expression after the two treatments and are related to bladder cancer, renal cell carcinoma and sexual addiction. The present study reveals the basic pattern of gene expression that was activated at ejaculation in the presence of 8-OH-DPAT or dapoxetine, providing preliminary gene expression information during rat ejaculation.

Addicted to love: What is love addiction and when should it be treated?

Recent research suggests that romantic love can be literally addictive. Although the exact nature of the relationship between love and addiction has been described in inconsistent terms throughout the literature, we offer a framework that distinguishes between a narrow view and a broad view of love addiction. The narrow view counts only the most extreme, harmful forms of love or love-related behaviors as being potentially addictive in nature. The broad view, by contrast, counts even basic social attachment as being on a spectrum of addictive motivations, underwritten by similar neurochemical processes as more conventional addictions. We argue that on either understanding of love-as-addiction, treatment decisions should hinge on considerations of harm and well-being rather than on definitions of disease. Implications for the ethical use of anti-love biotechnology are considered.

Are Borderline Personality Symptoms Associated With Compulsive Sexual Behaviors Among Women in Treatment for Substance Use Disorders? An Exploratory Study

OBJECTIVE

Extant literature has documented a significant relationship between borderline symptoms and substance use disorders. As supported in past work, there is a significant theoretical relationship between borderline symptoms and compulsive sexual behaviors because both disorders share common underlying behaviors and traits. There is no known research that has examined the empirical relationship between borderline symptoms and compulsive sexual behaviors in a population with substance use disorders. To fill this important gap in the literature, this relationship was examined in the current study.

METHOD

Medical records from 120 women admitted to a private, residential treatment program for substance use disorders were reviewed for the current study.

RESULTS

Hierarchical multiple regression analysis demonstrated that borderline symptoms were significantly associated with compulsive sexual behaviors after controlling for alcohol use and problems, drug use and problems, age, and positive impression management.

CONCLUSION

Results from this study provide potentially important research and clinical implications, which could ultimately aid treatment and reduce relapse. However, continued research is needed to further examine the relationship between symptoms and compulsive sexual behaviors.

The Relation Between Compulsive Sexual Behaviors and Aggression in a Substance-Dependent Population

Research supports a high comorbidity between compulsive sexual behaviors (CSBs) and SUDs, which are both classified by increased impulsivity. Literature has also indicated that increased impulsivity and substance use are associated with aggression. However, no known research has examined the relationship between CSBs and aggression among a substance dependent population. The purpose of the current study was to examine this relationship. Participants included 349 male patients in treatment for SUDs. Results indicated that after controlling for alcohol and drug use and problems and age, CSBs were significantly associated with total aggression, aggressive attitudes, physical aggression, and verbal aggression. This is the first known study to examine this relationship, thus continued research is needed to extend and replicate these findings.

A preliminary investigation of the relationship between early maladaptive schemas and compulsive sexual behaviors in a substance-dependent population

Past research has consistently demonstrated high co-occurrence between substance use disorders (SUDs) and compulsive sexual behaviors (CSBs). Numerous studies have also indicated that maladaptive core beliefs and early maladaptive schemas (EMS) are prevalent among individuals with SUDs and CSBs. However, research has yet to examine the relationship between EMS and CSBs among substance-dependent populations. Thus, the purpose of the current study was to examine this relationship in a sample of 198 men and 62 women in residential treatment for SUDs. Findings demonstrated that the five EMS domains were positively associated with CSBs. Results further demonstrated that patients meeting the cutoff score for CSBs scored significantly higher than patients not meeting the cutoff score for CSBs on the EMS domains of disconnection/rejection, impaired autonomy, and impaired limit. These findings suggest that there is an important and significant relationship between EMS and CSBs among adults in substance use treatment. Results from the current study indicate that EMS may provide a potentially important focus for treatment, particularly among individuals with co-morbid CSBs and SUDs. Given the preliminary nature of this study, continued research is needed to replicate and extend the findings from the current study.

Hypersexuality Addiction and Withdrawal: Phenomenology, Neurogenetics and Epigenetics

Hypersexuality has been defined as abnormally increased sexual activity. Epidemiological and clinical studies have shown that this non-paraphilic condition consists of "excessive" sexual behaviors and disorders accompanied by personal distress and social and medical morbidity. It is a very controversial and political topic in terms of how best to categorize it as similar or not similar to addictive behaviors including substance abuse. Hypersexual disorder is conceptualized as a non-paraphilic sexual desire disorder with impulsivity. Pathophysiological perspectives include dysregulation of sexual arousal and desire, sexual impulsivity, and sexual compulsivity. The nucleus accumbens, situated within the ventral striatum, mediates the reinforcing effects of drugs of abuse, such as cocaine, alcohol, nicotine, and food as well as music. Indeed, it is believed that this structure mandates behaviors elicited by incentive stimuli. These behaviors include natural rewards like feeding, drinking, sexual behavior, and exploratory locomotion. An essential rule of positive reinforcement is that motor responses will increase in magnitude and vigor if followed by a rewarding event. Here, we are hypothesizing that there is a common mechanism of action (MOA) for the powerful effects drugs, music, food, and sex have on human motivation. The human drive for the three necessary motivational behaviors "hunger, thirst, and sex" may all have common molecular genetic antecedents that, if impaired, lead to aberrant behaviors. We hypothesize that based on a plethora of scientific support hypersexual activity is indeed like drugs, food, and music that activate brain mesolimbic reward circuitry. Moreover, dopaminergic gene and possibly other candidate neurotransmitter-related gene polymorphisms affect both hedonic and anhedonic behavioral outcomes. There is little known about both the genetics and epigenetics of hypersexuality in the current literature. However, we anticipate that future studies based on assessments with clinical instruments combined with genotyping of sex addicts will provide evidence for specific clustering of sexual typologies with polymorphic associations. There have been some studies using electrophysiological techniques that do not support the view that hypersexuality is indeed similar to substance abuse and other behavioral addictions. The authors are also encouraging both clinical and academic scientists to embark on research using neuroimaging tools to examine natural dopaminergic agonistic agents targeting specific gene polymorphisms to "normalize" hypersexual behavior.

Neuroscience of Internet Pornography Addiction: A Review and Update

Many recognize that several behaviors potentially affecting the reward circuitry in human brains lead to a loss of control and other symptoms of addiction in at least some individuals. Regarding Internet addiction, neuroscientific research supports the assumption that underlying neural processes are similar to substance addiction. The American Psychiatric Association (APA) has recognized one such Internet related behavior, Internet gaming, as a potential addictive disorder warranting further study, in the 2013 revision of their Diagnostic and Statistical Manual. Other Internet related behaviors, e.g., Internet pornography use, were not covered. Within this review, we give a summary of the concepts proposed underlying addiction and give an overview about neuroscientific studies on Internet addiction and Internet gaming disorder. Moreover, we reviewed available neuroscientific literature on Internet pornography addiction and connect the results to the addiction model. The review leads to the conclusion that Internet pornography addiction fits into the addiction framework and shares similar basic mechanisms with substance addiction. Together with studies on Internet addiction and Internet Gaming Disorder we see strong evidence for considering addictive Internet behaviors as behavioral addiction. Future research needs to address whether or not there are specific differences between substance and behavioral addiction.

A Shared Molecular and Genetic Basis for Food and Drug Addiction: Overcoming Hypodopaminergic Trait/State by Incorporating Dopamine Agonistic Therapy in Psychiatry

This article focuses on the shared molecular and neurogenetics of food and drug addiction tied to the understanding of reward deficiency syndrome. Reward deficiency syndrome describes a hypodopaminergic trait/state that provides a rationale for commonality in approaches for treating long-term reduced dopamine function across the reward brain regions. The identification of the role of DNA polymorphic associations with reward circuitry has resulted in new understanding of all addictive behaviors.

Hypersexuality Addiction and Withdrawal: Phenomenology, Neurogenetics and Epigenetics

Hypersexuality is now part of the DSM-V and has been defined as abnormally increased sexual activity. Epidemiological and clinical studies have shown that this non-paraphilic condition consists of “excessive” sexual behaviors and disorders accompanied by personal distress and social and medical morbidity. Hypersexual disorder is conceptualized as primarily a non-paraphilic sexual desire disorder with impulsivity. Pathophysiological perspectives include dysregulation of sexual arousal and desire, sexual impulsivity, sexual addiction, and sexual compulsivity. The nucleus accumbens, situated within the ventral striatum, mediates the reinforcing effects of drugs of abuse, such as cocaine, alcohol, nicotine, and food as well as music. Indeed, it is believed that this structure mandates behaviors elicited by incentive stimuli. These behaviors include natural rewards like feeding, drinking, sexual behavior, and exploratory locomotion. An essential rule of positive reinforcement is that motor responses will increase in magnitude and vigor if followed by a rewarding event. Here, we are hypothesizing that there is a common mechanism of action (MOA) for the powerful effects drugs, music, food, and sex have on human motivation. The human drive for the three necessary motivational behaviors “hunger, thirst, and sex” may all have common molecular genetic antecedents that, if impaired, lead to aberrant behaviors. We hypothesize that based on a plethora of scientific support hypersexual activity is indeed like drugs, food, and music that activate brain mesolimbic reward circuitry. Moreover, dopaminergic gene and possibly other candidate neurotransmitter-related gene polymorphisms affect both hedonic and anhedonic behavioral outcomes. There is little known about both the genetics and epigenetics of hypersexuality in the current literature. However, we anticipate that future studies based on assessments with clinical instruments combined with genotyping of sex addicts will provide evidence for specific clustering of sexual typologies with polymorphic associations. The authors are also encouraging both clinical and academic scientists to embark on research using neuroimaging tools to examine natural dopaminergic agonistic agents targeting specific gene polymorphisms to “normalize” hyper- or hyposexual response.

Effects of number of cagemates on home cage ethanol drinking during proximal cagemate drinking (PCD) procedures in male and female CD-1 mice

The present experiment evaluated the effects of the Number of Cagemates (0 vs 1 vs 2) on home cage ethanol drinking during Proximal Cagemate Drinking (PCD) procedures in Male and Female CD-1 mice. Continuous-access home cage 2-bottle (ethanol vs. water) free-choice procedures were employed. PCD procedures eliminate the distracting effects of direct physical contact between Drinkers and their Cagemates on ethanol drinking by imposing a translucent plastic barrier strip between them. If direct physical contact distracts from drinking, then one Cagemate would drink more ethanol and more water than two Cagemates housed together on the same side of the barrier. This would be the case even if two Cagemates stimulated more ethanol drinking in the Drinker housed on the other side of the barrier, due to the social stimulation effects of additional Cagemates. Results revealed that the ethanol intake of Female Drinkers was directly related to the number of Cagemates on the other side of the barrier strip, but this social stimulation effect was not observed in Male Drinkers. For Male Cagemates and Female Cagemates, the single Cagemate provided elevated ethanol intake and elevated water intake relative to the ethanol intake and water intake of each Cagemate in the two Cagemates condition. The data revealed that direct physical contact between Cagemates reduced their ethanol intake, even while stimulating ethanol intake of the Drinker on the other side of the barrier, indicating that the effects of social stimulation on ethanol drinking are not entirely due to effects of modeling or peer pressure. The PCD procedures allow the evaluation of effects of a broad range of social factors on home cage ethanol drinking in mice.

Endogenous opioid-induced neuroplasticity of dopaminergic neurons in the ventral tegmental area influences natural and opiate reward

Natural reward and drugs of abuse converge on the mesolimbic pathway and activate common mechanism of neural plasticity in the nucleus accumbens. Chronic exposure to opiates induces plasticity in dopaminergic neurons of the ventral tegmental area (VTA), which regulates morphine reward tolerance. Here, we test the hypotheses that mating-induced release of endogenous opioids in the VTA causes morphological changes of VTA dopamine cells in male rats, which in-turn regulate the long-term expression of experience-induced reinforcement of sexual behavior. First, sexual experience decreased VTA dopamine soma size 1 and 7 days, but not 30 days after the last mating session. This effect was blocked with naloxone before each mating session; thus, VTA dopamine cell plasticity was dependent on action of endogenous opioids. In turn, VTA plasticity was associated with altered opiate reward, as sexually experienced males did not form conditioned place preference for 0.5 mg/kg morphine. Next, it was determined whether endogenous opioid action mediates sexual reward and memory in male rats treated with naloxone during mating experience, either systemically or intra-VTA. Naloxone did not prevent the initial experience-induced facilitation of sexual behavior over repeated mating sessions, or conditioned place preference for mating. However, naloxone treatment attenuated the longer-term expression of experience-induced facilitation of sexual behavior and neural activation in mesolimbic areas induced by mating-associated conditioned cues. Together, these data demonstrate that endogenous opioids during mating induce neural plasticity in VTA dopamine neurons that appear critical for morphine reward and long-term memory for natural reward behavior.

"Jello® shots" and cocktails as ethanol vehicles: parametric studies with high- and low-saccharin-consuming rats

Naïve humans and rats voluntarily consume little ethanol at concentrations above ~6% due to its aversive flavor. Developing procedures that boost intake of ethanol or ethanol-paired flavors facilitates research on neural mechanisms of ethanol-associated behaviors and helps identify variables that modulate ethanol intake outside of the lab. The present study explored the impact on consumption of ethanol and ethanol-paired flavors of nutritionally significant parametric variations: ethanol vehicle (gelatin or solution, with or without polycose); ethanol concentration (4% or 10%); and feeding status (chow deprived or ad lib.) during flavor conditioning and flavor preference testing. Individual differences were modeled by testing rats of lines selectively bred for high (HiS) or low (LoS) saccharin intake. A previously reported preference for ethanol-paired flavors was replicated when ethanol had been drunk during conditioning. However, indifference or aversion to ethanol-paired flavors generally obtained when ethanol had been eaten in gelatin during conditioning, regardless of ethanol concentration, feeding status, or caloric value of the vehicle. Modest sex and line variations occurred. Engaging different behavioral systems when eating gelatin, rather than drinking solution, may account for these findings. Implications for parameter selection in future neurobiological research and for understanding conditions that influence ethanol intake outside of the lab are discussed.

Effectively addressing addiction requires changing the language of addiction

Public knowledge and attitudes about addiction are largely inconsistent with scientific evidence. The gap between the facts and public and professional perceptions is due in part to the language used to describe the disease and those who have it. A key step in modifying public attitudes and improving how health professionals and policymakers address addiction is to better align the language of addiction with the scientific evidence. Unless we clarify the language, those with the disease will continue to experience the stigma associated with it and attempts to deliver comprehensive and effective evidence-based prevention, treatment, and disease management will be profoundly compromised.

Hypothesizing repetitive paraphilia behavior of a medication refractive Tourette's syndrome patient having rapid clinical attenuation with KB220Z-nutrigenomic amino-acid therapy (NAAT)

Background and aims Many patients presenting multiple behaviors including drug and food abuse as well as other pathological repetitive unwanted activities such as gambling, self-mutilation and paraphilias may not be appropriately diagnosed. Here we present a case of a male presenting many of these seemingly diverse behaviors and finally diagnosed with reward deficiency syndrome (RDS) by his attending physician. Methods The use of the dopamine agonist, ropinirole after two weeks showed improvement in terms of sexual behavior but tolerance set in and was discontinued especially when an infraction occurred with the patient's insurance. In this article, we carefully explore the potential of ropinirole to downregulate dopamine receptors causing adenylate cyclase receptor supersensitivity and tolerance a feature of neurotransmitter cross-talk. Based on previous scientific evidence showing KB220Znutrigenomic amino-acid therapy (NAAT) to rapidly (post one-hour) activate dopaminergic pathways in both the pre-frontal cortex cingulate gyrus (relapse loci) and ventral tegmental area-caudate-accumbens-putamen (craving and emotion loci) the patient was prescribed NAAT. Results and discussion Within one week of utilization the repetitive paraphilia was eliminated. There were also a number of other positive effects such as enhanced focus that persisted even after the patient stopped using KB220Z suggesting neuroplasticity (e.g. altruistic thoughts). However, these observed profound benefits require more in-depth study, especially in a large cohort against a placebo. While this report focused on a rapid response rather than long-term benefits previously associated with NAAT, it is somewhat encouraging and longer term required follow-up and larger placebo controlled studies are warranted before any definitive conclusions could be gleaned from this case report.

Dopamine Genetics and Function in Food and Substance Abuse

Having entered the genomics era with confidence in the future of medicine, including psychiatry, identifying the role of DNA and polymorphic associations with brain reward circuitry has led to a new understanding of all addictive behaviors. It is noteworthy that this strategy may provide treatment for the millions who are the victims of "Reward Deficiency Syndrome" (RDS) a genetic disorder of brain reward circuitry. This article will focus on drugs and food being mutuality addictive, and the role of dopamine genetics and function in addictions, including the interaction of the dopamine transporter, and sodium food. We will briefly review our concept that concerns the genetic antecedents of multiple-addictions (RDS). Studies have also shown that evaluating a panel of established reward genes and polymorphisms enables the stratification of genetic risk to RDS. The panel is called the "Genetic Addiction Risk Score (GARS)", and is a tool for the diagnosis of a genetic predisposition for RDS. The use of this test, as pointed out by others, would benefit the medical community by identifying at risk individuals at a very early age. We encourage, in depth work in both animal and human models of addiction. We encourage further exploration of the neurogenetic correlates of the commonalities between food and drug addiction and endorse forward thinking hypotheses like "The Salted Food Addiction Hypothesis".

Common Phenotype in Patients with Both Food and Substance Dependence: Case Reports

The understanding that genes play a significant role in reward dependence and associated behavioral and drug addictions is highlighted in the emergence of Reward Deficiency Syndrome (RDS). Here we show two case reports that unequivocally indicate the definite commonality between food and drug addiction. These human cases not atypically raise the question as to how to treat these two seemingly diverse addictions. We suggest that research directed in an attempt to induce natural activation of dopaminergic reward circuitry as a form of common therapy may indeed be parsimonious.

Pharmacotherapies for Overeating and Obesity

Obesity has become pandemic, and the annual cost in related illnesses and loss of productivity is already over $100 billion and rising. Research has shown that obesity can and does cause changes in behavior and in the brain itself that are very similar to changes caused by drugs of abuse. While food addiction is not the causal agent of all obesity, it is clear that many people no longer eat to survive, but instead survive to eat. This review considers the importance of the brain's reward system in food intake. The review also examines research developments and current treatments for obesity, including diet and exercise, psychotherapy, surgical interventions, and pharmacotherapies. Finally we discuss alterations in American society that are necessary for change to occur, and the diffculties therein.

Neurogenetic Impairments of Brain Reward Circuitry Links to Reward Deficiency Syndrome (RDS): Potential Nutrigenomic Induced Dopaminergic Activation

Work from our laboratory in both in-patient and outpatient facilities utilizing the Comprehensive Analysis of Reported Drugs (CARD)(™) found a significant lack of compliance to prescribed treatment medications and a lack of abstinence from drugs of abuse during active recovery. This unpublished, ongoing research provides an impetus to develop accurate genetic diagnosis and holistic approaches that will safely activate brain reward circuitry in the mesolimbic dopamine system. This editorial focuses on the neurogenetics of brain reward systems with particular reference to genes related to dopaminergic function. The terminology "Reward Deficiency Syndrome" (RDS), used to describe behaviors found to have an association with gene-based hypodopaminergic function, is a useful concept to help expand our understanding of Substance Use Disorder (SUD), process addictions, and other obsessive, compulsive and impulsive behaviors. This editorial covers the neurological basis of pleasure and the role of natural and unnatural reward in motivating and reinforcing behaviors. Additionally, it briefly describes the concept of natural dopamine D2 receptor agonist therapy coupled with genetic testing of a panel of reward genes, the Genetic Addiction Risk Score (GARS). It serves as a spring-board for this combination of novel approaches to the prevention and treatment of RDS that was developed from fundamental genomic research. We encourage further required studies.

Custom genotyping for substance addiction susceptibility genes in Jordanians of Arab descent

Background

Both environmental and genetic factors contribute to individual susceptibility to initiation of substance use and vulnerability to addiction. Determining genetic risk factors can make an important contribution to understanding the processes leading to addiction. In order to identify gene(s) and mechanisms associated with substance addiction, a custom platform array search for a genetic association in a case/control of homogenous Jordanian Arab population was undertaken. Patients meeting the DSM-VI criteria for substance dependence (n = 220) and entering eight week treatment program at two Jordanian Drug Rehabilitation Centres were genotyped. In addition, 240 healthy controls were also genotyped. The sequenom MassARRAY system (iPLEX GOLD) was used to genotype 49 single nucleotide polymorphisms (SNPs) within 8 genes (DRD1, DRD2, DRD3, DRD4, DRD5, BDNF, SLC6A3 and COMT).

Results

This study revealed six new associations involving SNPs within DRD2 gene on chromosome 11. These six SNPs within the DRD2 were found to be most strongly associated with substance addiction in the Jordanian Arabic sample. The strongest statistical evidence for these new association signals were from rs1799732 in the C/−C promoter and rs1125394 in A/G intron 1 regions of DRD2, with the overall estimate of effects returning an odds ratio of 3.37 (χ2 (2, N = 460) = 21, p-value = 0.000026) and 1.78 (χ2 (2, N = 460) = 8, p-value = 0.001), respectively. It has been suggested that DRD2, dopamine receptor D2, plays an important role in dopamine secretion and the signal pathways of dopaminergic reward and drug addiction.

Conclusion

This study is the first to show a genetic link to substance addiction in a Jordanian population of Arab descent. These findings may contribute to our understanding of drug addiction mechanisms in Middle Eastern populations and how to manage or dictate therapy for individuals. Comparative analysis with different ethnic groups could assist further improving our understanding of these mechanisms.

The addictive brain: all roads lead to dopamine

This article will touch on theories, scientific research and conjecture about the evolutionary genetics of the brain function and the impact of genetic variants called polymorphisms on drug-seeking behavior. It will cover the neurological basis of pleasure-seeking and addiction, which affects multitudes in a global atmosphere where people are seeking "pleasure states".