Genetic polymorphisms related to behavioral approach and behavioral inhibition scales

Dissecting the Hippocampal Regulation of Approach-Avoidance Conflict: Integrative Perspectives From Optogenetics, Stress Response, and Epigenetics

Psychiatric disorders are multifactorial conditions without clear biomarkers, influenced by genetic, environmental, and developmental factors. Understanding these disorders requires identifying specific endophenotypes that help break down their complexity. Here, we undertake an in-depth analysis of one such endophenotype, namely imbalanced approach-avoidance conflict (AAC), reviewing its significant dependency on the hippocampus. Imbalanced AAC is a transdiagnostic endophenotype, being a feature of many psychiatric conditions in humans. However, it is predominantly examined in preclinical research through paradigms that subject rodents to conflict-laden scenarios. This review offers an original perspective by discussing the AAC through three distinct lights: optogenetic modulation of the AAC, which updates our understanding of the hippocampal contribution to behavioral inhibition; the impact of environmental stress, which exacerbates conflict and strengthens the stress-psychopathology axis; and inherent epigenetic aspects, which uncover crucial molecular underpinnings of environmental (mal) adaptation. By integrating these perspectives, in this review we aim to underline a cross-species causal nexus between heightened hippocampal activity and avoidance behavior. In addition, we suggest a rationale to explore epigenetic pharmacology as a potential strategy to tackle AAC-related psychopathology. This review assumes greater significance when viewed through the lens of advancing AAC-centric diagnostics in human subjects. Unlike traditional questionnaires, which struggle to accurately measure individual differences in AAC-related dimensions, new approaches using virtual reality and computer games show promise in better focusing the magnitude of AAC contribution to psychopathology.

The interplay between parental care and OPRM1 in reward responsiveness

The Reinforcement Sensitivity Theory (RST) explains a variety of reward-motivated behaviors as the result of the activation of biologically-based systems. Inspired by the influences of parental bonding and opioid peptide on reward system, we investigated the contributions of parental bonding and mu-opioid receptor gene (OPRM1) towards motivation systems (i.e., the BAS, BIS-anxiety, and FFFS-fear). Results indicated that (1) parental care was negatively related to FFFS-fear, but parental overprotection was positively related to both FFFS-fear and BIS-anxiety; (2) parental care significantly interacted with OPRM1 rs1799971 in reward responsiveness with diathesis-stress model. Poor parental care reduced reward responsiveness among individuals with the G allele, but not those with the AA genotype. These findings from this study demonstrate a new gene-environment interactive mechanism of the RST.

Childhood adversity and impaired reward processing: A meta-analysis

BACKGROUND

Childhood adversity (CA) is associated with increased risk of psychopathology, and reward processing (RP) may be one of the underlying mechanisms. However, evidence on impaired RP in childhood adversity is theoretically and methodologically heterogeneous.

OBJECTIVE

To provide a quantitative overview of studies on the relation between childhood adversity and RP assessed at the behavioral and subjective levels, and identify differences between studies that influence the effect size.

PARTICIPANTS AND SETTING

Twenty-seven studies (overall N = 6801) were included.

METHODS

Peer-reviewed publications describing empirical studies on the relation between CA and behavioral and self-report measures of RP in humans were identified through systematic searches in six bibliographic databases. Effect sizes (r) were pooled using random-effects models. The potential moderator role of RP dimension, type of RP assessment, type of childhood adversity assessment, and age were examined.

RESULTS

Results indicated a small, but consistent association between CA and impaired RP (r = 0.12; 95% CI: 0.07, 0.16), with medium heterogeneity (I² = 62.43). The effect size was significantly larger (i.e., medium-sized) in studies that focused on reward learning rather than reward valuation and reward responsiveness; used cognitive tasks rather than self-report assessments of RP; and relied on official records rather than subjective reports of CA. There was evidence of publication bias, but overall effect size remained significant after imputation.

CONCLUSIONS

These results suggest that multidimensional RP impairments (e.g., deficits in reward learning, biased reward valuation) are a consistent marker of CA, and may represent mechanisms underlying the increased risk of psychopathology.

Quantitative behavioral genetic and molecular genetic foundations of the approach and avoidance strategies

Two studies examined genetic and environmental influences on traits proposed by the revised Reinforcement Sensitivity Theory (rRST) of personality. Both quantitative and molecular behavioral genetic methods were applied considering the effects of COMT, DRD2, HTR1A and TPH2 single nucleotide polymorphisms (SNPs). Study one included 274 monozygotic and 154 dizygotic twins for the quantitative behavioral study; and in study two there were 431 twins for the molecular genetic study. The Reinforcement Sensitivity Questionnaire was used to assess basic personality traits defined by the rRST. Univariate biometric modeling suggested that genetic influences accounted for 34-44% of variance of Behavioral Approach System (BAS), Behavioral Inhibition System (BIS) and Fight-Fligh-Freeze System. Molecular genetic analyses proposed the significant main effect of COMT SNP on the BAS and TPH2 SNP on the BIS, and pointed out epistatic effects of COMT x DRD2 on BAS and HTR1A x TPH2 on Fight. Results demonstrated substantial heritability for all rRST constructs, as well as for differences in the molecular genetic basis of both approach-related and avoidance-related dimensions.

The BDNF Val66Met polymorphism impacts victim's moral emotions following interpersonal transgression

Immoral behaviors make individuals abominate and punish transgressors. Inspired by the associations between the Val66Met polymorphism of brain-derived neurotropic factor (BDNF) gene and emotional responses following negative events, we investigated whether this polymorphism was also associated moral emotions such as punishment and forgiveness following interpersonal transgression. To do so, we categorized 340 individuals according to the BDNF Val66Met and assessed moral emotions by using 12 hypothetic scenarios in different conditions of intention and interpersonal consequence. The results indicated that this polymorphism was significantly associated with moral aversion and punishment towards transgressors. Victims with the Val/Val genotype expressed less aversion and punishment than the Met carriers, regardless of intention and interpersonal consequence. Moreover, this polymorphism was associated with forgiveness. Victims with the Val/Val genotype expressed more forgiveness than the Met carriers. Taken together, these findings highlight the importance of the BDNF Val66Met to moral emotions.

Threat sensitivity is associated with the healthcare source used most often: doctor's office, emergency room, or none at all

A significant proportion of American adults do not have a regular source of healthcare and the reasons for this shortfall are not fully understood. The objective of this study was to examine the relationship between individual differences in threat sensitivity and healthcare utilization in a survey of 483 African American men. Demographics, psychological characteristics, and health behaviors were assessed. The primary outcomes were: 1) most frequent source of healthcare utilization (doctor's office or clinic vs. emergency room vs. no place), and 2) frequency of healthcare utilization (one or more vs. no healthcare visits in the previous year). Data were analyzed with multivariable logistic regression. Results showed that threat sensitivity, insurance status, and age were associated with the most frequent source of healthcare utilization. Compared to men who most commonly used a doctor's office or clinic, men who tended to use an emergency room had higher levels of threat sensitivity and those with no usual healthcare source had lower levels of threat sensitivity. These findings fit with leading neurobiological theories of personality regarding threat sensitivity. From a pragmatic standpoint, these findings may also lend insight to the tailoring of health marketing messages designed to optimize utilization of healthcare resources.

[The interaction effect of ANKK1/DRD2 TaqIA and HTR2C Cys23Ser on approach motivation in schizophrenic patients and normals]

AIM

To evaluate the association of the DRD2 gene and DRD2 x HTR2C interaction with hedonic and activational aspects of approach motivation in schizophrenia.

MATERIAL AND METHODS

Genotypes at polymorphic loci DRD2 rs1800497 and HTR2C rs6318 (Cys23Ser) were identified in a sample that included 174 patients with schizophrenic spectrum disorders and 268 healthy subjects without a family history of psychoses. The participants completed the BIS/BAS and Temporal Experience of Pleasure Scale (TEPS).

RESULTS AND CONCLUSION

A MANCOVA with sex and age as covariates revealed the effect of the 'DRD2 x HTR2C x diagnosis' interaction on the BAS scores (p=0.033). The effect was significant for the Fun-Seeking and Drive scales. Among patients, the carriers of the DRD2 TT/CT x HTR2C GG/G genotype showed the highest scores on the both scales, and those with the minor alleles in the two loci had the lowest ones. Differences between these groups were nominally significant for both the Fun-Seeking and Drive, but did not survive the correction for multiple comparisons. Among controls, subjects without minor alleles demonstrated the highest scores on these two scales. They differed significantly from the carriers of the DRD2 TT/CT+HTR2C GG/G genotype on the Fun-Seeking (p=0.008). No effects of DRD2 and HTR2C on TEPS scores were found. In general, the results of the study can be interpreted in favor of the hypothesis about the role of the HTR2C and DRD2 genes interaction in the variability of the activational aspects of approach motivation in schizophrenia and healthy subjects. However, the lack of differences survived correction for multiple comparisons makes it difficult to interpret the revealed effects.

Behavioral approach and orbitofrontal cortical activity during decision-making in substance dependence

Behavioral approach, defined as behavior directed toward a reward or novel stimulus, when elevated, may increase one's vulnerability to substance use disorder. Behavioral approach has been associated with relatively greater left compared to right frontal activity; behavioral inhibition may be associated with relatively greater right compared to left frontal brain activity. We hypothesized that substance dependent individuals (SDI) would have higher behavioral approach than controls and greater prefrontal cortical activity during decision-making involving reward. We hypothesized that behavioral approach would correlate with left frontal activity during decision-making and that the correlation would be stronger in SDI than controls. 31 SDI and 21 controls completed the Behavioral Inhibition System/Behavioral Approach System (BIS/BAS) scales and performed a decision-making task during fMRI. Orbitofrontal (OFC) and dorsolateral prefrontal activity were correlated with BIS and BAS scores. Compared to controls, SDI had higher BAS Fun Seeking scores (p<0.001) and worse decision-making performance (p=0.004). BAS Fun Seeking correlated with left OFC activity during decision-making across group (r=0.444, p<0.003). The correlation did not differ by group. There was no correlation between BIS and right frontal activity. Left OFC may play a role in reward-related decision-making in substance use disorder especially in individuals with high behavioral approach.

An integrative study of motivation and goal regulation processes in subclinical anxiety, depression and hypomania

Research has implicated motivation and goal regulation in susceptibility to mood disorders. We studied for the first time key facets of motivation and goal regulation concurrently in relation to affective symptoms. The cross-national sample comprised 510 university students from the United States (n = 279) and United Kingdom (n = 231). Participants completed self-report measures of motivation, conditional goal setting, urgency, depression, anxiety, and mania risk. Structural Equation Modeling results found that behavioral activation system scores correlated negatively with depression and positively with mania risk, but were unrelated to anxiety. High conditional goal setting correlated uniquely with higher depression but not to anxiety or mania risk. Urgency correlated with higher anxiety, depression, and mania risk. Behavioral inhibition system scores correlated negatively with mania risk but unexpectedly did not correlate with anxiety in the multivariate model. The behavioral activation, behavioral inhibition, conditional goal setting, and urgency results showed shared and distinct patterns of relationships with depression, anxiety and mania risk. Our findings indicate unique and common risk vulnerabilities in depressive, anxious, and manic syndromes and extend an integrative knowledge of these syndromes in relation to goal regulation.