Reward Dependence Research Articles

The Discriminational Role of Cloninger's Temperament Model and Cognitive Emotion Regulation in the Discrimination of Tobacco Users

Objective: The purpose of this study was discriminating smokers from healthy people based on temperament and cognitive emotion regulation. Method: the present study has been a group classification design. The research population were all of girl and boy students in kerman. The final sample of research was including 200 participants (each group has 100 participants). For collect data used of cloninger's temperament questionnaire and cognitive emotion regulation questionnaire (short- form). Findings: in comparison with the healthy group, the mean of novelty seeking and inefficient cognitive emotion regulation was higher and the mean of persistence, self-directedness, reward dependence and co-perativeness was lower in the smoking group. However, there was no significant difference in terms of harm avoidance, self-transcendence and efficient cognitive emotion regulation. Conclusion: considering a person's profile in the Cloninger temperament model and cognitive emotion regulation strategies, it is possible to identify people who are prone to tobacco use and provide them with the necessary training.

The relationship between psychobiological dimensions of personality and internet gaming disorder: the role of positive and negative affects

Internet gaming disorder (IGD) is an important issue that was included as a tentative disorder in the DSM-5. The aim of the present study was to contribute to the increasing understanding of IGD by examining the indirect relationships between psychobiological components of personality, positive and negative affect, and IGD among a sample of Iranian university students. In a cross-sectional study, 481 Iranian university students (50.3% female; Mage = 22.41 years [SD = 4.62]) were recruited from four universities and completed self-report psychometric scales, including the Internet Gaming Disorder Scale (IGDS), Temperament and Character Inventory (TCI), and Positive and Negative Affect Schedule (PANAS). Structural equation modeling was used to empirically explore the relationships. The model of positive affect and negative affect being a mediator between psychobiological components of personality and IGD fit the data. Individuals with higher levels of negative affect had higher levels of IGD (r = 0.60, p < 0.001). Furthermore, bootstrapping results showed that psychobiological components of personality affected IGD via negative affect. Findings demonstrated that negative affect mediated the relationships between temperament dimensions of harm avoidance (β = .126), reward dependence (β = .054), persistence (β = −.127), as well as character dimensions of cooperativeness (β = −.047), and self-directedness (β = −.042) with IGD (all p-values <0.001). Findings contribute to the knowledge in the field, and support the proposed models showing that negative affect appears to have an important role in IGD. Clinical implications and study limitations are discussed.

Persistence, Reward Dependence, and Sensitivity to Reward Are Associated With Unexpected Salience Response in Girls but Not in Adult Women: Implications for Psychiatric Vulnerabilities

BackgroundAdolescence is a critical period for the development of not only personality but also psychopathology. These processes may be specific to sex, and brain reward circuits may have a role. Here, we studied how reward processing and temperament associations differ across adolescent and adult females. MethodsA total of 29 adolescent girls and 41 adult women completed temperament assessments and performed a classical taste conditioning paradigm during brain imaging. Data were analyzed for the dopamine-related prediction error response. In addition, unexpected stimulus receipt or omission and expected receipt response were also analyzed. Heat maps identified cortical-subcortical brain response associations. ResultsAdolescents showed stronger prediction error and unexpected receipt and omission responses (partial η2 = 0.063 to 0.166; p = .001 to .043) in insula, orbitofrontal cortex (OFC), and striatum than adults. Expected stimulus receipt response was similar between groups. In adolescents versus adults, persistence was more strongly positively related to prediction error (OFC, insula, striatum; Fisher’s z = 1.704 to 3.008; p = .001 to .044) and unexpected stimulus receipt (OFC, insula; Fisher’s z = 1.843 to 2.051; p = .014 to .033) and negatively with omission (OFC, insula, striatum; Fisher’s z = −1.905 to −3.069; p = .001 to .028). Reward sensitivity and reward dependence correlated more positively with unexpected stimulus receipt and more negatively with stimulus omission response in adolescents. Adolescents showed significant correlations between the striatum and FC for unexpected stimulus receipt and omission that correlated with persistence but were absent in adults. ConclusionsAssociations between temperamental traits and brain reward response may provide neurotypical markers that contribute to developing adaptive or maladaptive behavior patterns when transitioning from adolescence to adulthood.

Personality traits and BMI trends over three years in Japanese university students.

In Europe and America, associations between personality traits and body-mass index (BMI) have been reported. However, in Japan, the association between personality traits and BMI (i.e., thinness and obesity) has not been well studied. In this study, we investigated the relationship between Temperament and Character Inventory (TCI) personality traits and changes in BMI status among Japanese students during their university attendance. We measured the height and weight of 5,340 students in a Japanese university during annual medical checkups and calculated their BMI. The students’ personality traits were measured using the short Japanese version of the TCI at university admission. The participants were divided into seven groups based on how BMI changed from the first year to the fourth year at university. In men, compared to the group that maintained normal BMI status (N = 2,189) over time (i.e., the control group), the group that maintained thinness status (N = 226) were lower in Reward Dependence, and the group whose status improved from thinness to normal (N = 117) were higher in Harm Avoidance. In women, compared with the control group (N = 1,510), the group that maintained thinness status (N = 302) was lower in Novelty Seeking, and the group whose status worsened from normal to thinness (N = 127) was higher in Harm Avoidance. Weak associations were found between thinness and TCI personality traits among Japanese university students. Further elaboration of the relationship between obesity or thinness and personality traits may help to provide effective preventive interventions in these areas.

Psychopathogical status and personality correlates of problem gambling severity in sports bettors undergoing treatment for gambling disorder.

Background and aimsSports betting has been barely explored independently from other gambling behaviors. Little evidence is available regarding the factors affecting its severity in a clinical sample. The current study explores new determinants for sports betting severity in Spain by the inclusion of psychopathological distress and personality factors.MethodsA sample of 352 Spanish sports bettors undergoing treatment for gambling disorder was recruited. Multiple regression models were used to evaluate the effects of sociodemographic variables, the age of onset of gambling behavior, the global psychopathological distress (SCL-90R GSI) and the personality profile (TCI-R) on sports betting severity and their influence over frequency (bets per episode) and debts due to gambling.ResultsWe found that older age, higher psychopathological distress, lower self-directedness level, and higher novelty seeking level were predictors of gambling severity in Spanish sports bettors. The highest betting frequency was found in men, with the lowest education levels but the highest social status, the highest psychopathological distress, reward dependence score, and self-transcendence trait and the lowest persistence score. Debts were also associated to higher score in cooperativeness as well as older age.Discussion and conclusionsOur findings call for further exploration of factors affecting sports betting severity regarded as a separate gambling entity subtype, as some of the traditional factors typically found in gamblers do not apply to sports bettors or apply inversely in our country. Consequently, sports bettors might deserve specific clinical approaches to tackle the singularities of their gambling behavior.

The prevalence and features of schizophrenia among individuals with gambling disorder

Background-objectivesFew studies have analyzed the comorbid presence of gambling disorder (GD) with schizophrenia, its sociodemographic correlates and clinical implications. This study estimated the prevalence of the dual diagnosis (GD with schizophrenia) and the differences in the profiles of patients with and without the dual condition. MethodThe sample included n = 3,754 patients consecutively accepted for treatment for GD. Sociodemographics, gambling-related variables, psychopathological state and personality traits were assessed and compared between the groups. ResultsThe prevalence of schizophrenia within patients who met clinical criteria for GD was 4.4% (95% confidence interval: 3.8%–5.1%). Variables related to the dual presence of GD with schizophrenia were single marital status, lower education level, inactive working status, socioeconomic disadvantage, younger age, earlier onset of gambling problems, worse global psychopathological state and more dysfunctional personality profile (higher level in harm avoidance and lower level in cooperativeness, reward dependence, persistence and self-directedness). ConclusionThe presence of schizophrenia among patients with GD was around 4 times higher than the prevalence rate estimated in the reference general population. The differences in the profiles of GD patients with and without schizophrenia suggest that individuals with the dual diagnosis condition require unique assessment considerations and tailored treatment interventions specifically designed for the clinical and functioning higher risk.

Understanding the well-being of dentistry students.

The transactional model of stress is a framework describing the process for coping with stressful events as a relationship between the individual person and environment. This study aimed to investigate the associations between personality, learning environment and experiences of mental health for a cohort of Australian dentistry students. Students were invited in 2017 to complete an online questionnaire including the Depression, Anxiety and Stress Scale (DASS-21), The Dundee Ready Education Environment Measure (DREEM) and Cloninger's Temperament and Character Inventory (TCIR-140). Students were followed-up one year later, and generalised estimating equations were used. A total of 219 (response 73.5%) students participated in the study. Two personality profiles of dentistry students were identified. Group 1 were significantly higher in the traits persistence, self-directedness, cooperativeness and reward dependence, whereas Group 2 were significantly higher in harm avoidance. Students with Group 2 personality had a 3.12 (CI:1.72-5.65) increased odds of depression compared to Group 1 students. Compared to students with positive perceptions of the learning environment, students with negative perceptions had increased odds of stress (3.48, CI: 1.85-6.53), depression (2.71, CI: 1.57- 4.65) and anxiety (2.59, CI: 1.56-4.28). Students with personalities high in levels of self-directedness, cooperativeness and persistence and low in harm avoidance, as found in Group 1, demonstrate high levels of general well-being. Positive perceptions of the dentistry learning environment were found to be an important influence on students stress. This study highlighted a number of factors important to student well-being and provides direction for further investigation of interventions aimed at enhancing student well-being.

Brainstem glucose metabolism predicts reward dependence scores in treatment-resistant major depression.

It has been suggested that individual differences in temperament could be involved in the (non-)response to antidepressant (AD) treatment. However, how neurobiological processes such as brain glucose metabolism may relate to personality features in the treatment-resistant depressed (TRD) state remains largely unclear. To examine how brainstem metabolism in the TRD state may predict Cloninger's temperament dimensions Harm Avoidance (HA), Novelty Seeking (NS), and Reward Dependence (RD), we collected 18fluorodeoxyglucose positron emission tomography (18FDG PET) scans in 40 AD-free TRD patients. All participants were assessed with the Temperament and Character Inventory (TCI). We applied a multiple kernel learning (MKL) regression to predict the HA, NS, and RD from brainstem metabolic activity, the origin of respectively serotonergic, dopaminergic, and noradrenergic neurotransmitter (NT) systems. The MKL model was able to significantly predict RD but not HA and NS from the brainstem metabolic activity. The MKL pattern regression model identified increased metabolic activity in the pontine nuclei and locus coeruleus, the medial reticular formation, the dorsal/median raphe, and the ventral tegmental area that contributed to the predictions of RD. The MKL algorithm identified a likely metabolic marker in the brainstem for RD in major depression. Although 18FDG PET does not investigate specific NT systems, the predictive value of brainstem glucose metabolism on RD scores however indicates that this temperament dimension in the TRD state could be mediated by different monoaminergic systems, all involved in higher order reward-related behavior.

The association between the salivary cortisol level of mothers, children's temperament, and early childhood caries.

Multiple factors can affect early childhood caries (ECC). Maternal stress and child's temperament, as predictors of child behavior, are among factors that may be associated with ECC. The aim of this study was to evaluate the association between the salivary cortisol level of mothers as an indicator of maternal stress, child's temperament, and ECC. Ninety preschool children, who were divided into three groups of ECC, severe ECC (S-ECC), and caries-free (CF), were included in this study, as well as their mothers with no history of anxiety disorders. The salivary cortisol levels of mothers were analyzed using ELISA assay. Children were examined for the evidence of caries, using the decayed-missing-filled teeth index, based on the World Health Organization standard criteria. Child temperament was also assessed, using Cloninger's Preschool Temperament and Character Inventory, consisting of seven significant factors (cooperativeness, harm avoidance, novelty seeking, reward dependence, persistence, self-directing, and self-transcendence). The association between the salivary cortisol level of mothers and temperament of children with S-ECC was positive although it was not statistically significant (P > 0.05). Of seven temperament factors, only harm avoidance was significantly different between the CF and S-ECC groups (P = 0.016). Maternal stress and child's temperament were not associated with ECC. Based on the present findings, children with less harm avoidance may be more prone to S-ECC.

Evaluation of Temperament and Character Traits and Their Subscale Dimensions Associated with Major Depressive Disorder.

Objectives:The relationship between major depressive disorder (MDD) and, especially harm avoidance, self-directedness, and cooperativeness has been determined based on Cloninger’s psychobiological personality model; there are not enough studies in the literature on the role of the subdimensions. Therefore, the aim of this study was to compare the patients with MDD and healthy controls in terms of temperament and character traits and especially subdimensions and thus to determine the role and predictive value of temperament and character subdimensions in major depression patients.Methods:The sample of this cross-sectional study consisted of 105 participants, 65 of whom were MDD patients, and 40 healthy controls, who voluntarily agreed to participate in the study. Sociodemographic data form, temperament and character inventory, and Hamilton depression rating scale were administered to the participants.Results:Compared with healthy controls, patients with MDD had lower self-directedness (p<0.001), cooperativeness (p=0.017), persistence (p<0.001), self-transcendence (p=0.001), and higher harm avoidance (p<0.001) scores. While there was no significant difference in novelty seeking (p=0.774); it was determined that MDD patients got higher scores in “Impulsiveness” (p=0.013) and lower scores in “Exploratory excitability” (p=0.001) subscales. Reward dependence has been identified as the only personality trait that there was no significant difference between major depression patients and healthy controls (p=0.511). As a result of the logistic regression analysis performed to determine the predictors of temperament and character subdimensions in major depression patients, only three temperament and character traits “Fatigability, Purposefulness, and Spiritual Acceptance” were determined as significant predictors (p<0.001). Fatigability was determined to be a serious risk factor, increasing the probability of MDD 3.6 times (p<0.001); purposefulness and spiritual acceptance were found to be protective personality traits that together reduced the probability of MDD by 0.8 times (p<0.001).Conclusion:This study shows that the risk of developing MDD is increased in individuals with low self-directedness, cooperativeness, persistence, and self-transcendence profiles, and whereas with prominent Harm avoidance personality traits. Therapeutic interventions, especially considering the temperament and character traits of “Fatigability, Purposefulness, and Spiritual Acceptance” determined in our study, may contribute positively to MDD treatment.

Association of COMT, BDNF and 5-HTT functional polymorphisms with personality characteristics.

Background: The real impact of genetic factors on personality is still unknown, even if in literature about 50% of variance in personality traits are considered genetically determined. The determination of the genetic variance in personality traits could promote psychological well-being and the prevention of psychopathologies, because there are many experimental evidences showing that mental illness is associated to personality. Numerous studies have showed that Catechol-O-methyltransferase (COMT), brain derived neurotrophic factor (BDNF) and serotonin transporter (5-HTT) are genes whose variants are associated with personality traits. This aim of this study is the investigation of the association between personality traits and 5-HTTLPR/rs255315-HTT promoter variant, COMT Val158Met and BDNF Val66Met gene polymorphisms. Methods: The sample was composed by 132 healthy female students. Genomic DNA was extracted from buccal swab, while personality was assessed with Cloninger's Temperament and Character Inventory-Revised (TCI-R). Linear discriminant analysis was used to analyze how personality characteristics can differentiate individuals in relation to their genetic polymorphisms. Results: Data showed that the temperament trait Reward Dependence discriminated individuals with different BDNF variants; Novelty Seeking and Harm Avoidance discriminated individuals with different 5HTTLPR variants; Persistence discriminated individuals with different COMT variants. Conclusions: Since these traits are connected to psychological diseases as depression, social anxiety, anorexia and obsessive-compulsive disorders of personality, the study of their genetic component can be used as intermediary issue to better define the connection between genes and predisposition toward maladaptive behavior and mental illness.

Is Anxiety-Inducing VR Experienced Differently Depending on Personality? The Mediating Role of Presence

This study attempted to investigate the role of presence in an anxiety-inducing virtual reality (VR) experience and explain possible individual differences in the feeling of presence. More specifically, it was investigated if the feeling of presence (a) differed by personality and (b) affected individual levels of anxiety. This study utilized the psychobiological model of the Temperament and Character Inventory (TCI) to study personality in the context of virtual reality exposure therapy (VRET). In total, thirty six individuals participated in a lab experiment in which anxiety-inducing VR content was experienced through a head-mounted display. The results suggested that individuals with high levels of cooperativeness and self-transcendence experienced increased levels of presence, which further enhanced cognitive anxiety levels. On a physiological level, cooperativeness and reward dependence enhanced somatic anxiety (respiration), but presence was not a significant mediating factor.

Associations of multidimensional temperament and character profiles with cognition and sensorimotor gating in individuals at risk for schizophrenia-spectrum disorders: preliminary findings

Cloninger’s biopsychological model for personality distinguishes between Temperament [Novelty Seeking, Harm Avoidance (HA), Reward Dependence (RD), Persistence (PS)], and Character [Self-Directedness (SD), Cooperativeness (CO), Self-Transcendence (ST)] traits. Cloninger has also described three sets of complex interactions among these traits, which can be summarized as a linked network of three cubes. Within each cube, the different combinations of the sub-dimensions formulate multidimensional profiles that describe personality more accurately compared with their individual constituents. The aim of the present study was to examine differences of these multidimensional profiles in cognitive functions and Prepulse Inhibition (PPI) in unaffected relatives of schizophrenia-spectrum patients and control individuals. We assessed 114 unaffected relatives of schizophrenia-spectrum patients and 122 controls for Temperament/Character traits, a wide range of cognitive functions, and PPI of the acoustic startle reflex. The relatives had higher Ηarm Avoidance and Self-Transcendence along with lower Reward Dependence, Persistence, Self-Directedness and Cooperativeness scores as well as lower PPI and poorer cognition compared with controls. We also found a) unequal distribution of relatives and controls in several “disadvantageous” profiles associated with the schizophrenia-spectrum, b) the Schizotypal/Disorganized, Apathetic and Fragile profiles had poorer emotional decision making and attention switching, respectively, compared with their “advantageous” counterparts and c) the Adventurous, Independent, Bossy and Resilient profiles had higher PPI compared with their counterparts. These findings further highlight the significance of personality determinants of cognitive processes and have potential implications in early intervention programs in the schizophrenia-spectrum.

Gambling disorder seeking treatment patients and tobacco use in relation to clinical profiles

ObjectivesTobacco smoking and gambling disorder (GD) often co-occur. However, few studies have assessed the extent to which cigarette smoking may serve to classify and/or better define GD behaviour profiles. MethodsAmong a large sample of n = 3,652 consecutive treatment-seeking patients with GD (91% men). Smokers were compared to non-smokers across different sociodemographic, clinical, psychopathological and personality variables. The effect sizes for the means and the proportion differences between the groups were estimated. An evaluation of the smoking changes over the last 15 years was also performed. ResultsFrom the total sample, 62.4% of gamblers reported tobacco use. A decreasing linear trend in tobacco use was observed within the studied period, women having a more irregular pattern. The use of tobacco was linked to the use of alcohol and other illegal drugs. Gamblers who smoke, as compared to those who don’t, presented lower education levels, lower social position indexes and active employment. They were younger, with an earlier age of onset, shorter duration of the gambling behavior, higher GD severity, more psychological symptoms, higher scores in novelty seeking and lower scores in reward dependence, self-directedness and self-transcendence. ConclusionsGamblers seeking treatment who smoke display particular social, clinical, psychological, temperamental and character features different from non-smoking gamblers, suggesting that the presence or absence of comorbid smoking condition in GD should always be considered when developing an optimal treatment, as gamblers who smoke might need treatment strategies different from non-smoking gamblers.

Empathy for patient care in medical students: new evidence on the importance of self-transcendence

ABSTRACT Empathy is essential in clinical care to achieve patient satisfaction, treatment adherence and health outcomes. Understanding how personality traits might influence the development of medical students’ empathy for patient care is important in medical education. Previous studies have shown associations between medical students’ personality and empathy. This study aims to explore the associations between temperament and character and empathy for patient care in a sample of young medical students. Participants were 299 second-year Italian medical students. They completed the Italian versions of the Jefferson Scale of Empathy for medical students (JSE-S) and the Temperament and Character Inventory (TCI-140). Correlation and regression analyses were performed. Significant positive low correlations were found between empathy and Reward Dependence, Cooperativeness and Self-transcendence. The regression model of the sex and personality dimensions explained 14% of the variance in empathy with two significant predictors: sex (B = 4.034) and Self-transcendence (B = 0.361). This study confirms that female medical students are more empathetic than males. It also suggests that the greater students’ Self-transcendence is, the more empathetic towards patient care they are. Attention to medical students’ personality should be present within medical curricula, as it may help to generate methods of enhancing and sustaining the empathy of students.

Personality traits mediate the association between perceived parental bonding and well-being in adult volunteers from the community

BackgroundPrevious studies reported that subjective well-being in adulthood correlates with perceived parental bonding in childhood as well as personality traits. However, whether personality traits mediate the effect of perceived parental bonding on well-being or not has not been reported to date. In this study, we hypothesized that ‘parental care and overprotection’ in childhood affect ‘well-being’ in adulthood through various ‘personality traits’, and analyzed this using structural equation modeling.MethodsA total of 402 adult volunteers from the community provided responses to the following questionnaires: 1) Parental Bonding Instrument, 2) Temperament and Character Inventory, and 3) The Subjective Well-being Inventory. Two structural equation models were designed and the maximum likelihood estimation method was used for covariance structure analysis.ResultsParental care in childhood directly increased well-being in adulthood and indirectly increased it through personality traits (harm avoidance, reward dependence, and self-directedness). Parental overprotection in childhood had no direct effect on well-being in adulthood but decreased well-being in adulthood indirectly through personality traits (harm avoidance, reward dependence, and self-directedness) and increased it through one personality trait (self-transcendence).ConclusionsThis study showed that the influences of perceived parental bonding on well-being in adulthood are mediated by self-directedness, harm avoidance, reward dependence, and self-transcendence among the seven personality dimensions evaluated by the Temperament and Character Inventory.

The endocannabinoid system in humans: significant associations between anandamide, brain function during reward feedback and a personality measure of reward dependence.

Preclinical evidence indicates that the endocannabinoid system is involved in neural responses to reward. This study aimed to investigate associations between basal serum concentrations of the endocannabinoids anandamide (AEA) and 2-arachidonylglycerol (2-AG) with brain functional reward processing. Additionally, a personality measure of reward dependence was obtained. Brain functional data were obtained of 30 right-handed adults by conducting fMRI at 3 Tesla using a reward paradigm. Reward dependence was obtained using the subscale reward dependence of the Tridimensional Personality Questionnaire (TPQ). Basal concentrations of AEA and 2-AG were determined in serum. Analyzing the fMRI data, for AEA and 2-AG ANCOVAs were calculated using a full factorial model, with condition (reward > control, loss > control) and concentrations for AEA and 2-AG as factors. Regression analyses were conducted for AEA and 2-AG on TPQ-RD scores. A whole-brain analysis showed a significant interaction effect of AEA concentration by condition (positive vs. negative) within the putamen (x = 26, y = 16, z = -8, F13.51, TFCE(1, 54) = 771.68, k = 70, PFWE = 0.044) resulting from a positive association of basal AEA concentrations and putamen activity to rewarding stimuli, while this association was absent in the loss condition. AEA concentrations were significantly negatively correlated with TPQ reward dependence scores (rspearman = -0.56, P = 0.001). These results show that circulating AEA may modulate brain activation during reward feedback and that the personality measure reward dependence is correlated with AEA concentrations in healthy human volunteers. Future research is needed to further characterize the nature of the lipids' influence on reward processing, the impact on reward anticipation and outcome, and on vulnerability for psychiatric disorders.

Adherence to oral chemotherapy: Evidence from a randomised clinical trial.

To evaluate the efficacy of a reinforcement message (RM) administered by a hospital pharmacist on adherence, through a randomised study involving patients undergoing oral chemotherapy from which an objective outcome measure and patients' subjective opinions were collected. A secondary aim was to detect which psychological or clinical factors influence adherence. Forty patients were enrolled and randomised to an experimental group (EG) or a control group (CG). The EG received a 10-minute RM provided by a hospital pharmacist with a doctor and a nurse. The CG received the standard of care. To measure adherence, plasma drug concentration and subjective evaluation were taken during the visits, in addition to a psychological assessment (coping strategies, psychological distress and personality traits). The EG reported higher drug levels and a statistically significant higher mean score on the subjective evaluation. A linear regression model highlighted statistically significant differences in the plasma drug concentration, after considering toxicity and dose reduction and controlling for the Reward Dependence Scale of the Temperament and Character Inventory between the EG and the CG. Adequate information and education on the therapy, using an RM strategy provided by a hospital pharmacist, seems to positively influence adherence to the treatment.

Personality dimensions could explain resilience in patients with eating disorders.

Resilience can be defined as the ability to maintain health in the face of adversity. Resilience has been associated with personality traits. Personality traits in the context of Eating Disorders (ED) have also been examined. However, the relationship between resilience and personality profile in patients with ED has not been studied. The aim of this study is to investigate whether personality dimensions impact on resilience, in patients with ED, compared to healthy participants. Connor and Davidson resilience scale, as a measure of resilience and temperament-character inventory, as a measure of personality dimensions, were completed by 100 participants: 50 (50%) healthy University students (controls subgroup) and 50 (50%) patients with ED, matched on age and gender. Patients with ED showed lower resilience than healthy participants and scored higher on harm avoidance, and lower on reward dependence, self-directedness and cooperativeness than controls. Lower harm avoidance, higher persistence and higher self-directedness were associated with resilience in both subgroups. Self-directedness and persistence predicted resilience in both subgroups. Only Harm Avoidance predicted resilience in patients' subgroup. To our knowledge, there are no existing data examining the effect of personality dimensions in resilience, in the context of ED. We found that only the effect of Harm Avoidance in resilience was different among the participants' subgroups. In conclusion, Harm Avoidance could explain differences in resilience between healthy participants and patients with ED. Level III: case-control analytic study.

The cannabinoid CB2 receptor agonist LY2828360 synergizes with morphine to suppress neuropathic nociception and attenuates morphine reward and physical dependence

The opioid crisis has underscored the urgent need to identify safe and effective therapeutic strategies to overcome opioid-induced liabilities. We recently reported that LY2828360, a slowly signaling G protein-biased cannabinoid CB2 receptor agonist, suppresses neuropathic nociception and attenuates the development of tolerance to the opioid analgesic morphine in paclitaxel-treated mice. Whether beneficial effects of LY2828360 are dependent upon the presence of a pathological pain state are unknown and its impact on unwanted opioid-induced side-effects have never been investigated. Here, we asked whether LY2828360 would produce synergistic anti-allodynic effects with morphine in a paclitaxel model of chemotherapy-induced neuropathic pain and characterized its impact on opioid-induced reward and other unwanted side-effects associated with chronic opioid administration. Isobolographic analysis revealed that combinations of LY2828360 and morphine produced synergistic anti-allodynic effects in suppressing paclitaxel-induced mechanical allodynia. In wildtype (WT) mice, LY2828360 blocked morphine-induced reward in a conditioned place preference assay without producing reward or aversion when administered alone. The LY2828360-induced attenuation of morphine-induced reward was absent in CB2 knockout (CB2KO) mice. In the absence of a neuropathic pain state, LY2828360 partially attenuated naloxone-precipitated opioid withdrawal in morphine-dependent WT mice, and this withdrawal was itself markedly exacerbated in CB2KO mice. Moreover, LY2828360 did not reliably alter morphine-induced slowing of colonic transit or attenuate tolerance to morphine antinociceptive efficacy in the hot plate test of acute nociception. Our results suggest that cannabinoid CB2 receptor activation enhances the therapeutic properties of opioids while attenuating unwanted side-effects such as reward and dependence that occur with sustained opioid treatment.