A comparison of impulsivity, depressive symptoms, lifetime stress and sensation seeking in healthy controls versus participants with cocaine or methamphetamine use disorders

Predictors of drug and substance abuse among school-going adolescents living in drug hotspot in Malaysia

This study explored the pressing issue of drug and substance abuse (DSA) among adolescents in drug hotspots in Malaysia. The Malaysian Anti-drug Agency (AADK) has identified 155 hotspot areas across Malaysia, of which 78 were randomly selected as the study sites. These areas were identified as having extreme drug-related activities such as drug trafficking and drug-related crimes. According to the literature, several factors influence adolescents to be involved in DSA. Therefore, understanding the risk factors in the context of Malaysian school-going adolescents is of utmost importance. The study examined, in particular, a wide range of potential predictors, including socioeconomic factors, peer influence, family dynamics, educational experiences, drug access, and community characteristics. Adolescents in the hotspot areas were selected by means of a cross-sectional survey design with a cluster sampling method. The sample comprised 3382 school-going adolescents, and the data were collected through face-to-face interviews. The logit model method with STATA software was used to analyse the data. The findings of the study revealed that school-going adolescents with disciplinary issues face a two-fold increase in the risk of becoming current drug users compared to their peers. Further, those exhibiting externalising behaviours, such as aggression and rule-breaking, also face greater odds of becoming involved in DSA. Drug pushers were identified as the most significant risk factor, with adolescents exposed to them being 46 times more likely to become current drug users. The factors of friends and family also contribute significantly to adolescent drug involvement. However, adolescents with academic-related issues may be less involved if they have the protective factor of better coping skills. These findings will contribute to efforts to mitigate drug addiction and drug-related activities, particularly in high-risk communities, as well as help policymakers and healthcare professionals develop targeted interventions and generally promote the well-being of adolescents.

Exploration of the Relationships Between Stress and Distinct Pain and Sleep Disturbance Profiles in Patients Undergoing Chemotherapy

BACKGROUND

Unrelieved pain and sleep disturbance are common symptoms in oncology patients. Increased stress may be an underlying cause for both symptoms.

OBJECTIVES

The purposes of this study were to identify subgroups of outpatients with distinct pain and sleep disturbance profiles and to evaluate differences among these subgroups in demographic and clinical characteristics. Differences in global stress, cancer-specific stress, and cumulative life stress, as well as resilience and coping, were evaluated.

METHODS

Patients (N = 1343) completed self-report questionnaires for demographic and clinical characteristics and stress, resilience, and coping. Latent profile analysis was used to identify subgroups of patients with distinct pain and sleep disturbance profiles. Differences among the subgroups were determined using parametric and nonparametric tests.

RESULTS

Three distinct profiles were identified (ie, No Pain + Moderate Sleep Disturbance (SD) (27.6%), Moderate Pain + Moderate SD (38.6%), Severe Pain + High SD (33.8%)). Compared with the other 2 classes, Severe Pain + High SD class was younger, had fewer years of education, was more likely to be female, more likely to live alone, less likely to be employed, and had a higher level of comorbidity. This class had the highest stress scores and was more likely to report higher rates of adverse childhood experiences.

CONCLUSION

Over 70% of our sample reported clinically meaningful levels of both symptoms, and 33.8% reported relatively high rates of adverse childhood experiences.

IMPLICATION FOR PRACTICE

Clinicians need to perform routine assessments, particularly of adverse childhood experiences, and initiate appropriate referrals.

Repeated Cocaine Intake Differentially Impacts Striatal D2/3 Receptor Availability, Psychostimulant-Induced Dopamine Release, and Trait Behavioral Markers of Drug Abuse

Current research indicates that altered dopamine (DA) transmission in the striatum contributes to impulsivity and novelty-seeking, and it may mediate a link concerning a higher susceptibility to drug abuse. Whether increased susceptibility to drug abuse results from a hyperdopaminergic or hypodopaminergic state is still debated. Here, we simultaneously tracked changes in DA D2/3 receptor (D2/3R) availability and amphetamine-(AMPH)-induced DA release in relation to impulsivity and novelty-seeking prior to, and following, cocaine self-administration (SA) in Roman high- (RHA) and low- (RLA) avoidance rats. We found that high-impulsive/high novelty-seeking RHA rats exhibited lower D2/3R availabilities and higher AMPH-induced DA release in the striatum that predicted higher levels of cocaine intake compared with RLAs. Cocaine SA did not alter striatal D2/3R availability or impulsivity in RHA or RLA rats. Critically, cocaine exposure led to a baseline-dependent blunting of stimulated DA release in high-impulsive/high novelty-seeking RHA rats only, and to a baseline-dependent increase in novelty-seeking in low-impulsive/low novelty-seeking RLA rats only. Altogether, we propose that susceptibility to drug abuse results from an innate hyper-responsive DA system, promoting impulsive action and novelty-seeking, and producing stronger initial drug-reinforcing effects that contribute to the initiation and perpetuation of drug use. However, with repeated cocaine use, a tolerance to drug-induced striatal DA elevations develops, leading to a compensatory increase in drug consumption to overcome the reduced reward effects.

Association between Polymorphism rs1799732 of DRD2 Dopamine Receptor Gene and Personality Traits among Cannabis Dependency

Compared to other addictive substances, patients with cannabis addiction are significantly outnumbered by those who report dependence on other, more addictive substances. Unfortunately, most cannabis addiction goes untreated, and among those who choose treatment, the requirements are much higher for adolescents and young adults.

THE AIM OF THE STUDY

To examine the relationship of cannabinoid dependency in the genetic context-the association between the rs1799732 polymorphism of the DRD2 gene and psychological traits and anxiety.

METHODS

The study group consisted of 515 male volunteers. Of these, 214 patients were diagnosed with cannabis addiction and 301 were non-addicted. Patients were diagnosed with NEO Five-Factor Personality Inventory (NEO-FFI), and State-Trait Anxiety Inventory (STAI) questionnaires. The interactions between personality traits and polymorphisms in the DRD2 rs1799732 gene were investigated in a group of cannabis-addicted patients and non-addicted controls using the real-time PCR method.

RESULTS

Compared to the control group, the case group obtained significantly higher scores on the STAI State, STAI Trait, Neuroticism and Openness scales, as well as lower scores on the Extraversion, Agreeableness, and Conscientiousness scales. There was no statistically significant difference between addicts and the control group in the frequency of genotypes, but there was a statistically significant difference between addicts and the control group in the frequency of the DRD2 allele rs179973. The multivariate ANOVA analysis showed a statistically significant influence of the DRD2 rs1799732 genotype on the NEO-FFI agreeableness scale and a statistically significant effect of addiction to cannabinoids or its absence on the NEO-FFI agreeableness scale score.

CONCLUSIONS

Studying homogeneous subgroups-as in our study-seems reasonable, particularly when combined with genetic determinants and psychological traits. In multigenic and multifactorial entities, such a strategy has a future.

Exploring the Posting of Nude Photographs on Reddit in Relation to Self-Esteem, Perceived Attractiveness, Narcissism, and Sensation Seeking

While many scholars have explored the sharing of nude photographs one-to-one (i.e., sexting), few have examined the sharing of nudity in a one-to-many context. The current study examined the sharing of nude photographs on Reddit, framing the practice as an act of disinhibited online behavior. A survey (n = 628) was conducted to assess whether Redditors levels of sensation seeking, self-esteem, perceived attractiveness, and narcissism would be related to whether or not they posted nude photographs on the site. Results indicated that posting nudity on Reddit was significantly associated with higher perceived attractiveness and narcissism, but not sensation seeking or self-esteem. The role of gender and sexual orientation in the posting of nudity online was also assessed, and an overrepresentation of nude content produced by females and bisexual persons, as well as an underrepresentation of nude content produced by males and heterosexuals, was found. Findings are discussed in relation to self-concept, sexual health, and the online disinhibition effect.

Patients with Methamphetamine Use Disorder Show Highly Utilized Proactive Inhibitory Control and Intact Reactive Inhibitory Control with Long-Term Abstinence

Methamphetamine use disorder (MUD) is a chronic brain disorder that involves frequent failures of inhibitory control and relapses into methamphetamine intake. However, it remains unclear whether the impairment of inhibitory control in MUD is proactive, reactive or both. To address this issue, the current study used the conditional stop-signal task to assess proactive and reactive inhibitory control in 35 MUD patients with long-term abstinence and 35 matched healthy controls. The results showed that MUD patients with long-term abstinence had greater preparation costs than healthy controls, but did not differ in performance, implying a less efficient utilization of proactive inhibitory control. In contrast, MUD patients exhibited intact reactive inhibitory control; reactive but not proactive inhibitory control was associated with high sensation seeking in MUD patients with long-term abstinence. These findings suggest that proactive and reactive inhibitory control may be two different important endophenotypes of addiction in MUD patients with long-term abstinence. The current study provides new insight into the uses of proactive and reactive inhibitory control to effectively evaluate and precisely treat MUD patients with long-term abstinence.

Electrophysiological Evidence of Enhanced Processing of Novel Pornographic Images in Individuals With Tendencies Toward Problematic Internet Pornography Use

Novelty seeking is regarded as a core feature in substance use disorders. However, few studies thus far have investigated this feature in problematic Internet pornography use (PIPU). The main aim of the present study was to examine group differences in electrophysiological activity associated with novelty processing in participants with high tendencies toward PIPU vs. low tendencies using event-related potentials (ERPs). Twenty-seven participants with high tendencies toward PIPU and 25 with low tendencies toward PIPU completed a modified three-stimulus oddball task while electroencephalogram (EEG) was recorded. Participants were instructed to detect neutral target stimuli from distracting stimuli. The distracting stimuli contained a familiar sexual stimulus and a set of novel sexual stimuli. The novel-familiar difference waves were calculated to identify specific group difference in novelty effect. While both groups demonstrated a sustained novelty effect in the late positive potential (LPP) within the 500–800 ms time windows, the novelty effect was greater in the high tendencies toward PIPU group than in the low tendencies toward PIPU group. This result suggests that individuals with high tendencies toward PIPU allocate more attentional resources for novelty processing. Enhanced brain responding to novel sexual stimuli may facilitate pornographic consumption and play an essential role in the development and maintenance of PIPU.

Higher stress and symptom severity are associated with worse depressive symptom profiles in patients receiving chemotherapy

PURPOSE

In a sample of oncology patients, identify subgroups of patients with distinct depressive symptom profiles and evaluate for differences in demographic and clinical characteristics, levels of stress and resilience, and the severity of common co-occurring symptoms.

METHODS

Patients (n = 1327) had a diagnosis of breast, gastrointestinal, gynecological, or lung cancer; had received chemotherapy within the preceding four weeks; and were scheduled to receive at least two additional cycles of chemotherapy. Demographic and clinical characteristics, stress, resilience, and co-occurring symptoms were evaluated at enrollment. Depressive symptoms were evaluated using the Center for Epidemiological Studies-Depression (CES-D) scale a total of six times over two cycles of chemotherapy. Latent profile analysis (LPA) was used to identify subgroups of patients (i.e., latent classes) with distinct depressive symptom profiles using the six CES-D scores.

RESULTS

Based on the findings from the LPA, 47.3% of the patients were classified as "None"; 33.6% as "Subsyndromal"; 13.8% as "Moderate"; and 5.3% as "High". Compared to None class, patients in the Subsyndromal, Moderate, and High classes had a lower functional status, a higher comorbidity burden, and a self-reported diagnosis of depression or back pain. Those patients with higher levels of depressive symptoms reported higher levels of stress, lower levels of resilience, and increased severity of co-occurring symptoms.

CONCLUSIONS

Inter-individual variability in depressive symptoms was associated with demographic and clinical characteristics, multiple types of stress and levels of resilience, as well as with the increased severity of multiple co-occurring symptoms. The risk factors associated with worse depressive symptom profiles can assist clinicians to identify high risk patients and initiate more timely supportive care interventions.

Pierre C, Bimschleger H, Gao J, Cheng R, Polesskaya O, Solberg Woods LC, Palmer AA, Chen H. Genome-Wide Association Study on Three Behaviors Tested in an Open Field in Heterogeneous Stock Rats Identifies Multiple Loci Implicated in Psychiatric Disorders

Many personality traits are influenced by genetic factors. Rodents models provide an efficient system for analyzing genetic contribution to these traits. Using 1,246 adolescent heterogeneous stock (HS) male and female rats, we conducted a genome-wide association study (GWAS) of behaviors measured in an open field, including locomotion, novel object interaction, and social interaction. We identified 30 genome-wide significant quantitative trait loci (QTL). Using multiple criteria, including the presence of high impact genomic variants and co-localization of cis-eQTL, we identified 17 candidate genes (Adarb2, Ankrd26, Cacna1c, Cacng4, Clock, Ctu2, Cyp26b1, Dnah9, Gda, Grxcr1, Eva1a, Fam114a1, Kcnj9, Mlf2, Rab27b, Sec11a, and Ube2h) for these traits. Many of these genes have been implicated by human GWAS of various psychiatric or drug abuse related traits. In addition, there are other candidate genes that likely represent novel findings that can be the catalyst for future molecular and genetic insights into human psychiatric diseases. Together, these findings provide strong support for the use of the HS population to study psychiatric disorders.

Potential roles of the gut microbiota in the manifestations of drug use disorders

Drug use disorders (DUDs) not only cause serious harm to users but also cause huge economic, security, and public health burdens to families and society. Recently, several studies have shown that gut microbiota (GM) can affect the central nervous system and brain functions. In this review, we focus on the potential role of the GM in the different stages of DUDs. First, the GM may induce individuals to seek novel substances. Second, the gut microbiota is involved in the decomposition and absorption of drugs. Symptoms of individuals who suffer from DUDs are also related to intestinal microorganisms. Third, the effects of the GM and its metabolites on drug relapse are mainly reflected in the reward effect and drug memory. In conclusion, recent studies have preliminarily explored the relationship between GM and DUDs. This review deepens our understanding of the mechanisms of DUDs and provides important information for the future development of clinical treatment for DUDs.

Worst Pain Severity Profiles of Oncology Patients Are Associated With Significant Stress and Multiple Co-Occurring Symptoms

Little is known about the associations between pain, stress, and co-occurring symptoms in oncology patients. Purpose was to identify subgroups of patients with distinct worst pain profiles and evaluate for differences among the subgroups in demographic and clinical characteristics, as well as stress and symptom scores. Oncology outpatients (n = 1305) completed questionnaires prior to their second or third chemotherapy cycle. Worst pain intensity was assessed 6 times over 2 chemotherapy cycles using a 0 to 10 numeric rating scale. The 371 patients (28.4%) who had ≤1 occurrence of pain over the 6 assessments were classified as the None class. For the remaining 934 patients whose data were entered into the latent profile analysis, 3 distinct worst pain profiles were identified (ie Mild [12.5%], Moderate [28.6%], Severe [30.5%]). Compared to None class, Severe class had fewer years of education and a lower annual income; were less likely to be employed and married; less likely to exercise on a regular basis, had a higher comorbidity burden, and a worse functional status. Compared to None class, Severe class reported higher levels of general, disease-specific, and cumulative life stress and lower levels of resilience, as well as higher levels of depressive symptoms, anxiety, fatigue, sleep disturbance, and cognitive dysfunction. This study is the first to identify distinct worst pain profiles in a large sample of oncology patients receiving chemotherapy and associated risk factors. PERSPECTIVE: Unrelieved pain remains a significant problem for oncology patients receiving chemotherapy. High levels of stress and co-occurring symptoms contribute to a more severe pain profile in these patients.

Application of amide proton transfer imaging for the diagnosis of neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

This study aimed to evaluate cerebral amide proton transfer signal intensity (SI) among controls, hypoxic-ischemic encephalopathy (HIE) neonates with normal conventional magnetic resonance imaging (HIE/MRI-) findings, and HIE neonates with abnormal conventional MRI (HIE/MRI+) findings.

METHODS

Forty neonates diagnosed with neonatal HIE and sixteen normal neonates were evaluated. All neonates underwent conventional MRI scans and APT imaging. Cerebral APT SIs were compared to identify cerebral regions with significant APT changes among sixteen controls, thirteen HIE/MRI- patients, and twenty-seven HIE/MRI+ patients.

RESULTS

Significantly increased APT SIs were observed in the HIE/MRI- group compared with controls, in the left insula, right occipital lobe, left cingulate gyrus (posterior part), and corpus callosum. Significantly increased APT SIs were found in the HIE/MRI+ group compared with controls, in the right anterior temporal lobe (medial part), anterior parts of the right parahippocampal and ambient gyri, left superior temporal gyrus (middle part), left insula, left cingulate gyrus (posterior part), and right lentiform nucleus. No significant APT SI differences were observed in the cerebellum and brainstem among the three groups.

CONCLUSION

Amide proton transfer imaging plays an important role in detecting hypoxic-ischemic encephalopathy regardless of conventional MRI findings. Changes in APT signal intensity may provide important insights into the characterization of the cerebral internal environment. This study suggests that APT imaging could be used as a complement to conventional MRI in the detection of hypoxic-ischemic encephalopathy in clinical practice.

Impulsivity in cocaine users compared to matched controls: Effects of sex and preferred route of cocaine use

BACKGROUND

Impulsivity has been identified as playing a role in cocaine use. The purpose of this study was to explore self-report measures of impulsivity in large groups of male and female cocaine users and matched controls and to determine if differences in impulsivity measures within a group of cocaine users related to self-reported money spent on cocaine and route of cocaine use.

METHODS

Eight self-report impulsivity measures yielding 34 subscales were obtained in 230 cocaine users (180 M, 50 F) and a matched group of 119 healthy controls (89 M, 30 F). Correlational analysis of the questionnaires revealed 2 factors: Impulsive Action (Factor 1) consisting of many traditional impulsivity measures and Thrill-seeking (Factor 2) consisting of delay discounting, sensation and thrill seeking.

RESULTS

Sex influenced within group comparisons. Impulsive Action scores did not vary as a function of sex within either group. But, male controls and male cocaine users had greater Thrill-seeking scores than females within the same group. Sex also influenced between group comparisons. Male cocaine users had greater Impulsive Action scores while female cocaine users had greater Thrill-seeking scores than their sex-matched controls. Among cocaine users, individuals who preferred insufflating ("snorting") cocaine had greater Thrill-seeking scores and lower Impulsive Action scores than individuals who preferred smoking cocaine. Individuals who insufflate cocaine also spent less money on cocaine.

CONCLUSIONS

Greater Impulsive Action scores in males and Thrill-seeking scores in females were associated with cocaine use relative to controls.

Psychological Symptoms and Stress Are Associated With Decrements in Attentional Function in Cancer Patients Undergoing Chemotherapy

BACKGROUND

Decrements in attentional function-perceived effectiveness in everyday functioning related to cognitive dysfunction-are frequently reported by cancer patients during treatment. However, patients vary widely in their experiences of changes in attentional function.

OBJECTIVE

The aim of this study was to understand differences in attentional function among cancer patients during chemotherapy.

METHODS

Patients (n = 1329) undergoing chemotherapy were assessed at 6 time points during 2 rounds of chemotherapy. Latent profile analysis was used to identify subgroups of patients based on patterns in changes on the Attentional Function Index. Differences among the subgroups in demographic and clinical characteristics, psychological symptoms, and stress were evaluated.

RESULTS

Three latent classes (ie, high, moderate, and low attentional function) were identified. Patients in the low and moderate classes were younger, more likely to be female, and less likely to be employed compared with those in the high class. Patients in the low class had higher levels of depressive and anxiety symptoms, cancer-related distress, and perceived stress compared with those in the moderate class, who, in turn, reported higher levels of these symptoms compared with those in the high class.

CONCLUSIONS

Different experiences of changes in self-perceived attentional function are associated with psychological symptoms in cancer patients.

IMPLICATIONS FOR PRACTICE

Relationships between changes in attentional function and psychological symptoms and stress suggest that clinicians should attend to the potential that patients' cognitive and psychological experiences may be closely linked and may need to be addressed as related phenomena. Clinical trials are needed that evaluate treatments for both attentional and psychological symptoms.

The sensation seeking trait confers a dormant susceptibility to addiction that is revealed by intermittent cocaine self-administration in rats

Heightened sensation seeking is associated with an increased risk of substance use disorder in clinical populations. In rats, sensation seeking is often examined by measuring locomotor reactivity to a novel environment. So-called high responders (HR) acquire self-administration of psychostimulants more quickly and consume higher amounts of drug compared to low responder (LR) rats, indicating that the HR trait might confer a stronger addiction propensity. However, studies of addiction-like behaviors in HR vs LR rats have typically utilized self-administration paradigms that do not dissociate individual differences in the hedonic/reinforcing and motivational properties of a drug. Moreover, little attention has been given to whether HR rats are more susceptible to drug-access conditions that promote a state-dependent addiction phenotype. We report that on a behavioral economics task, HR rats have higher preferred brain-cocaine levels compared to LR rats but do not differ with respect to their demand elasticity for cocaine. In contrast, when tested on an intermittent access schedule of cocaine self-administration, which has been shown to promote several addiction-related endophenotypes, HR rats exhibit greater escalation of intake and more drastic reductions in cocaine demand elasticity. Together, these data indicate that the HR trait does not confer higher extant addiction behavior, but rather that this phenotype is associated with a propensity for addiction that remains dormant until it is actuated by intermittent drug intake. These findings reveal a 'trait' (HR) by 'state' (intermittent drug intake) interaction that produces a strong addiction-like phenotype. This article is part of the special issue on 'Vulnerabilities to Substance Abuse'.

Evaluation of the relationship between the gene expression level of orexin-1 receptor in the rat blood and prefrontal cortex, novelty-seeking, and proneness to methamphetamine dependence: A candidate biomarker

BACKGROUND

previous studies have suggested that methamphetamine (METH) abuse may affect orexin regulation. However, the data regarding the relationship between the current level of orexin and the vulnerability to METH abuse are minimal. Here, we have investigated the correlation between the gene expression level of the orexin-1 receptor (OX1R) in the rat prefrontal cortex (PFC) and blood lymphocytes and susceptibility to METH dependence and its impact on novelty-seeking behavior.

METHODS

male Wistar rats were first examined for novelty-seeking behavior by the novel object recognition test, and the expression level of OX1R in their blood lymphocytes was evaluated by real-time PCR. Then, the susceptibility to METH abuse was investigated by voluntary METH oral consumption test. According to the amounts of METH consumption, the animals were divided into two groups of METH preferring and non-preferring. Half of the rats in each group were sacrificed, and the level of OX1R in their blood lymphocytes and PFC tissue was measured. The other half were sacrificed for the same reason after two weeks of drug abstinence.

RESULTS

The indexes of novelty-seeking behavior were significantly higher in the METH- preferring group compared to the non-preferring animals. Furthermore, the expression level of OX1R in the blood lymphocytes and PFC in the preferring group was considerably higher than the non-preferring group.

CONCLUSION

Up-regulation of the mRNA expression level of OX1R in the lymphocytes and PFC may predict vulnerability to the METH consumption and novelty-seeking, which may serve as a potential biomarker for METH abuse.

Within-animal comparisons of novelty and cocaine neuronal ensemble overlap in the nucleus accumbens and prefrontal cortex

Novelty seeking is a personality trait associated with an increased vulnerability for substance abuse. In rodents, elevated novelty seeking has been shown to be a predictor for elevated drug self-administration and compulsive use. While previous studies have shown that both novelty and drugs of abuse have actions within similar mesocorticolimbic regions, little is known as to whether the same neural ensembles are engaged by these two stimuli. Using the TetTag mouse model and Fos immunohistochemistry, we measured neurons engaged by novelty and acute cocaine exposure, respectively in the prefrontal cortex (PFC) and nucleus accumbens (NAc). While there was no significant impact of novelty exposure on the size of the EGFP+ ensemble, we found that cocaine engaged significantly more Fos+ neurons in the NAc, while stress increased the size of the Fos+ ensemble in the PFC. Analysis of ensemble reactivation was specific to the emotional valence of the second stimuli. We found that a greater proportion of the EGFP+ ensemble was reactivated in the groups that paired novelty with a positive (cocaine) or neutral (saline) experience in the NAc, while the novelty/stress paired groups exhibited significantly less ensemble overlap in the PFC. However, only in the NAc shell was this increase in ensemble overlap specific to those exposed to both novelty and cocaine. This suggests that the NAc shell, but not the NAc core or PFC, may play an important role in general reward processing by engaging a similar network of neurons.

Higher levels of stress and different coping strategies are associated with greater morning and evening fatigue severity in oncology patients receiving chemotherapy

PURPOSE

A cancer diagnosis and associated treatments are stressful experiences for most patients. Patients' perceptions of stress and their use of coping strategies may influence fatigue severity. This study extends our previous work describing distinct profiles of morning (i.e., Very Low, Low, High, and Very High) and evening (i.e., Low, Moderate, High, and Very High) fatigue in oncology patients by evaluating for differences in stress and coping strategies among these fatigue classes.

METHODS

This longitudinal study evaluated for changes in morning and evening fatigue in oncology patients (n = 1332) over two cycles of chemotherapy (CTX). Patients completed measures of cumulative exposure to stressful life events (SLEs) (i.e., the Life Stressor Checklist-Revised), general stress (i.e., Perceived Stress Scale [PSS]), cancer-specific stress (i.e., Impact of Event Scale-Revised [IES-R]), and coping strategies (i.e., Brief Cope). Differences among the latent classes were evaluated using analyses of variance, Kruskal-Wallis, or chi-square tests.

RESULTS

Patients in both the Very High morning and evening fatigue classes reported higher numbers of and a higher impact from previous SLEs and higher PSS scores than the other fatigue classes. The IES-R scores for the Very High morning fatigue class met the criterion for subsyndromal PTSD. Patients in the Very High evening fatigue class used a higher number of engagement coping strategies compared with the Very High morning fatigue class.

CONCLUSIONS

Our findings suggest that interventions to reduce stress and enhance coping warrant investigation to decrease fatigue in patients undergoing CTX.

Quality of Life in Patients With Methamphetamine Use Disorder: Relationship to Impulsivity and Drug Use Characteristics

BACKGROUND

The quality of life (QOL) of patients with methamphetamine use disorder (MAUD) is increasingly recognized as an important outcome. Previous studies have found that impulsivity is negatively associated with QOL in mental disorders, but this relationship is rarely confirmed in patients with MAUD. We hypothesized that impulsivity is negatively correlated with QOL in patients with MAUD based on previous findings. In addition, a variety of drug use characteristics of patients that may potentially affect their QOL need to be further explored. Therefore, the purpose of this study was to explore the relationship between impulsivity, multiple drug use characteristics, and QOL in patients with MAUD.

METHODS

A total of 379 patients with MAUD were recruited, and the majority of them were male (85.5%), with an average age of 33.93 ± 7.08 years. Two psychiatrists conducted semi-structured interviews with methamphetamine (MA) users in two compulsory drug rehabilitation centers to obtain their demographics and drug use characteristics. The Barratt Impulsiveness Scale-11 (BIS-11) and Brief WHO Quality of Life Assessment (WHOQOL-BREF) were used to assess patients' impulsivity and QOL, respectively. Correlation and univariate regression analysis were used to explore the relationships between impulsivity, a series of drug use characteristics and patients' QOL in different domains. Further multiple linear regression analysis was used to identify what extent the above clinical variables explained the variations in patients' QOL.

RESULTS

Age, marital status, employment, and various drug use characteristics were significantly associated with at least one QOL domain. Among them, married and full-time job were positively correlated with QOL, while others were negatively correlated with QOL. The total score of BIS-11 was significantly negatively correlated with all four domains of QOL. Impulsivity, a range of drug use characteristics and certain demographic characteristics collectively explained varying degrees of variation in different domains of QOL.

CONCLUSIONS

Impulsivity and various drug use characteristics can significantly predict QOL in all fields of MAUD patients. In addition, we have also found differences in the predictors of QOL in different domains. Overall, this study provides clinical guidance for the treatment of MAUD patients, that is, management of impulsivity in patients with MAUD may help improve their QOL and even sustain their drug rehabilitation.

Prefrontal GABA and glutamate levels correlate with impulsivity and cognitive function of prescription opioid addicts: A 1 H-magnetic resonance spectroscopy study

AIM

Prescription opioids are psychoactive substances that can elicit many neuropsychological effects. There are no studies that directly demonstrate the effects of prescription opioid addiction (POA) on the human brain. This study aimed to quantify γ-aminobutyric acid (GABA) and glutamate (Glu) levels in the prefrontal cortex (PFC) of POA patients using proton magnetic resonance spectroscopy (¹ H-MRS), and to explore their association with impulsive behavior and cognitive impairment.

METHODS

Thirty-five patients with a definitive clinical diagnosis of codeine-containing cough syrup dependence and 35 matched healthy controls underwent neuropsychological assessments, namely the Barratt Impulsiveness Scale (BIS-11) and the Montreal Cognitive Assessment Scale (MoCA). Point-resolved spectroscopy was performed to detect GABA and glutamate within the medial PFC, and the corresponding levels were estimated using jMRUI and corrected for fraction of cerebrospinal fluid in the ¹ H-MRS voxel. The difference in metabolite levels between groups and the correlation between metabolite levels and psychometric scores in patients were analyzed statistically.

RESULTS

The peak level predominantly consisting of GABA with a relatively small influence of other chemicals (GABA+) was lower and that of glutamate was higher in the PFC of POA patients than in healthy controls. GABA+ levels correlated negatively with BIS-11 scores but correlated positively with MoCA scores. In contrast, glutamate levels showed a positive correlation with BIS-11 scores but no significant correlation with MoCA scores.

CONCLUSION

The quantitative in vivo measurement of GABA and glutamate levels in the PFC by ¹ H-MRS could be a reliable way to evaluate impulsivity and cognitive function of POA.

Cognition and Related Neural Findings on Methamphetamine Use Disorder: Insights and Treatment Implications From Schizophrenia Research

Despite the prevalence of methamphetamine (meth) use disorder, research on meth is disproportionately scarce compared to research on other illicit drugs. Existing evidence highlights cognitive deficits as an impediment against daily function and treatment of chronic meth use. Similar deficits are also observed in schizophrenia, and this review therefore draws on schizophrenia research by examining similarities and differences between the two disorders on cognition and related neural findings. While meth use disorder and schizophrenia are two distinct disorders, they are highly co-morbid and share impairments in similar cognitive domains and altered brain structure/function. This narrative review specifically identifies overlapping features such as deficits in learning and memory, social cognition, working memory and inhibitory/impulse control. We report that while working memory deficits are a core feature of schizophrenia, such deficits are inconsistently observed following chronic meth use. Similar structural and functional abnormalities are also observed in cortical and limbic regions between the two disorders, except for cingulate activity where differences are observed. There is growing evidence that targeting cognitive symptoms may improve functional outcome in schizophrenia, with evidence of normalized abnormal brain activity in regions associated with cognition. Considering the overlap between meth use disorder and schizophrenia, targeting cognitive symptoms in people with meth use disorder may also improve treatment outcome and daily function.

Associations between the dopamine D4 receptor gene polymorphisms and personality traits in elite athletes

Personality traits and temperament may affect sports performance. Previous studies suggest that dopamine may play an important role in behavior regulation and physical exercise performance. The aim of this study is to determine associations between dopamine D4 receptor gene (DRD4 Ex3) polymorphisms and personality traits (such as neuroticism, extraversion, openness, agreeability and conscientiousness) in elite combat athletes. A total of 302 physically active, unrelated, self-reported Caucasian participants were recruited for this study. The participants consisted of 200 elite male combat athletes and 102 healthy male participants (control group). For personality trait measurements, the NEO Five-Factor Personality Inventory (NEO-FFI) and the State-Trait Anxiety Inventory questionnaires were used. For the genetic assays, blood was collected and all samples were genotyped using the real-time PCR method. A 2 x 3 factorial ANOVA revealed statistically significant differences on the Openness NEO Five Factor Inventory scale for both examined factors, i.e. sport status and genetics DTD4 Ex3. Combat athletes achieved higher scores on the Conscientiousness NEO-FFI scale when compared to controls (7.18 vs 5.98). On the other hand, combat athletes scored lower on the Openness scale in comparison with control group (4.42 vs. 4.63). Subjects with the DRD4 Ex3 s/s genotype had lower results on the openness scale in comparison with participants with the DRD4 Ex3 s/1 genotype (4.01 vs. 4.57) and higher DRD4 Ex3 1/1 genotype (4,01 vs. 3,50). In conclusion, we found an association between the dopamine D4 receptor gene in variable number tandem repeat (VNTR) polymorphisms and athletic status for two NEO-FFI factors: Openness and Conscientiousness. The DRD4 exon 3 polymorphism may be associated with the selected personality traits in combat athletes, thereby modulating athletes’ predisposition to participate in high risk sports.

Predictors of Successful HIV Care Re-engagement Among Persons Poorly Engaged in HIV Care

The Data to Care (D2C) strategy uses HIV surveillance data to identify persons living with HIV (PLWH) who are poorly engaged in care and offers assistance with care re-engagement. We evaluated HIV care re-engagement among PLWH in Seattle & King County, Washington after participation in a D2C program and determined whether variables available at the time of the D2C interview predicted subsequent re-engagement in care. We defined successful re-engagement as surveillance evidence of either continuous care engagement (≥ 2 CD4 counts or HIV RNA results ≥ 60 days apart) or viral suppression (≥ 1 HIV RNA < 200 copies/mL) in the year following the D2C interview. Predictor variables included client characteristics, beliefs about HIV care, and scores on psychosocial assessment scales. Half of participants successfully re-engaged in care. We did not find any significant predictors of re-engagement except viral suppression at the time of the D2C interview. Close follow-up is needed to identify which D2C participants need additional assistance re-engaging in care.

The Ankyrin Repeat and Kinase Domain Containing 1 Gene Polymorphism (ANKK1 Taq1A) and Personality Traits in Addicted Subjects

The Taq1A polymorphism located in the ANKK1 gene is one of the most widely studied polymorphisms in regards to the genetics of behavior and addiction. The aim of our study was to analyze this polymorphism with regard to personality characteristics and anxiety measured by means of the Personality Inventory—(NEO Five-Factor Inventory—NEO—FFI) and the State-Trait Anxiety Inventory (STAI) in polysubstance addicted subjects. The study group consisted of 600 male volunteers, including 299 addicted subjects and 301 controls. Psychiatrists recruited members for both groups. Addiction was diagnosed in the case group. In the control group mental illness was excluded. The same psychometric test and genotyping using the real-time PCR (polymerase chain reaction) method was performed for both groups. The results were investigated by means of multivariate analysis of the main effects Multi-factor ANOVA. Significantly higher scores on the scale of STAI state and Neuroticism and Openness traits, as well as lower scores on the scales of Extraversion, Agreeability, and Conscientiousness, were found in the case group subjects, compared to the controls. Differences in frequency of genotypes and alleles of Taq1A polymorphism between the studied groups were not found. Multi-factor ANOVA of addicted subjects and control subjects and the ANKK1 Taq1A variant interaction approximated the statistical significance for the STAI state. The main effects ANOVA of both subjects’ groups were found for the STAI state and trait, the Neuroticism scale, the Extraversion scale, and the Agreeability scale. The ANKK1 Taq1A main effects approximated the statistical significance of the STAI trait. Our study shows not only differences in personality traits between addicted and non-addicted subjects, but also the possible impact of ANKK1 on given traits and on addiction itself.

Cognitive dysfunction in individuals with cocaine use disorder: Potential moderating factors and pharmacological treatments

It is well-documented in the literature that individuals repeatedly exposed to cocaine exhibit cognitive impairment and that cognitive dysfunction is a risk factor for poor treatment outcomes in those with cocaine use disorder (CUD). Specific deficits related to attention, episodic memory, working memory, and executive functioning are the most common deficits noted in this population. Given that cognitive impairment is a risk factor for poor treatment outcomes in those with CUD, identifying possible moderating factors contributing to and/or exacerbating cocaine-related cognitive deficits is of great importance. Some of these factors may include premorbid intellectual functioning, cocaine use patterns, polysubstance use, comorbid emotional symptoms, and sleep dysfunction. It is plausible that by identifying moderating factors impacting cognition, behavioral interventions can then be modified accordingly and/or treatment regimens can be augmented with pharmacological interventions (e.g., cognitive enhancing agents), leading to a reduction in treatment attrition and improved treatment outcomes. The currently available treatments for CUD are mainly behavioral with variable efficacy, and even though there have been great preclinical and clinical research efforts focused on medication development for CUD, there are currently no Food and Drug Administration-approved medications for CUD. A description of some of the several potential moderating factors, along with some pharmacological treatments which have been shown to ameliorate, at least to some extent, cognitive dysfunction in those with CUD are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Enrichment-induced differences in methamphetamine drug discrimination in male rats

Rats raised in an enriched environment show a decrease in sensitivity to the subjective effects of the psychostimulant d-amphetamine. The purpose of the present study was to determine if environmental enrichment during development alters the subjective effects of the more commonly abused drug methamphetamine. Male Sprague-Dawley rats were raised in either an enriched (EC) or an isolated condition (IC). EC and IC rats were trained on a two-lever operant procedure to discriminate 1.0 mg/kg (i.p.) methamphetamine from saline. Following acquisition of the discrimination a methamphetamine generalization curve (0.1-1.0 mg/kg) was determined. The antagonistic effects of dopamine D₁ receptor antagonist SCH23390 (0.0075-0.06 mg/kg) and the dopamine D₂ receptor antagonist eticlopride (0.01-0.3 mg/kg) were also tested. Finally, the ability of nicotine (0.05-0.5 mg/kg) to generalize and the ability of the nicotinic receptor antagonist mecamylamine (0.125-0.5 mg/kg) to antagonize the discriminative stimulus effects of methamphetamine were determined. EC rats were less sensitive to discriminative stimulus effects of methamphetamine compared to IC rats at a low 0.3 mg/kg dose and showed full antagonism of methamphetamine discrimination following SCH23390 compared to IC rats. There were no environmentally-induced differences in the effects of eticlopride. Nicotine only partially generalized to the effects of methamphetamine in both EC and IC rats. While mecamylamine failed to antagonize the effects of methamphetamine in either EC or IC rats. These results suggest that environmental enrichment decreases sensitivity to the discriminative effects of methamphetamine and the differences may be mediated through changes in the D₁ dopamine receptor.

Differentiating motives for nonmedical prescription stimulant use by personality characteristics

Nonmedical prescription stimulant use (NPS) is increasing, particularly among college students. College students typically engage in NPS for cognitive enhancement, recreational, and appetite/weight-related purposes; however, little research has used these motives to identify specific risk for, or consequences of, NPS. Moreover, there may be unique risk factors for motive-specific NPS that have yet to be explored, such as relevant personality traits (i.e., distress tolerance, impulsivity, and perfectionism) that are associated with NPS in general. Therefore, this study aimed to examine whether NPS users and nonusers could be differentiated via facets of impulsivity, perfectionism, and distress tolerance, and whether users could be further differentiated by reported motive for use based on these traits. Midwestern university undergraduate students (N = 668) who were enrolled in a psychology research pool completed an online survey assessing demographics, NPS and motives, and measures of distress tolerance, impulsivity, and perfectionism. Participants were primarily female (78%) and aged 18-54 (M = 20.10, SD = 3.19) years. Univariate and multivariate analysis of variance tests revealed associations between lifetime NPS and higher impulsivity, higher perfectionism, and lower distress tolerance. Further tests revealed NPS for appetite/weight-related purposes was associated with lower distress tolerance, while NPS for recreational purposes was associated with higher impulsivity. These findings contribute novel information regarding NPS motives and personality constructs. This information may aid in comprehensive identification of high-risk individuals for NPS and inform the development of specialized prevention and intervention efforts.

Associations Between the Dopamine D4 Receptor and DAT1 Dopamine Transporter Genes Polymorphisms and Personality Traits in Addicted Patients

Many factors are involved in addiction. The dopaminergic system is thought to be the key element in this process. The mesolimbic dopamine system is a crucial element in the reward system. Changes in this system are thought to be leading to substance use disorders and dependence. Therefore, for our study we chose an analysis of two polymorphisms in genes (Variable Number of Tandem Repeats in DRD4 and DAT1) responsible for dopaminergic transmission, which might be implicated in the scores of personality traits measured by the NEO-FFI test. The study group consisted of 600 male volunteers—299 addicted subjects and 301 controls. Both groups were recruited by psychiatrists; in the case group addiction was diagnosed; in the controls a mental illness was excluded. In both groups the same psychometric test and genotyping by the PCR VNTR method were performed. The results were investigated by a multivariate analysis of the main effects ANOVA. In the presented study no DRD4 main effects were found for any of the analyzed traits but the DRD4 main effects approximated to the statistical significance for the extraversion scale. However, no DAT1 main effects were found for any of the analyzed traits but the DAT1 main effects approximated to the statistical significance for the agreeability scale.These associations open new possibilities for addiction research.

NGF gene polymorphisms are not associated with heroin dependence in a Taiwanese male population

BACKGROUND AND OBJECTIVES

Heroin dependence (HD) is a chronic relapsing brain illness with substantial heritability. Nerve growth factor (NGF) is a crucial modulator in the neurodevelopment, and may be a key mediator of reward processes in HD. The purpose of this genetic study was to investigate whether NGF gene polymorphisms associate with the occurrence of HD and the specific personality traits of patients with HD.

METHODS

We selected a homogeneous Han Chinese male population to overcome possible confounding effects of population and gender. For the study, 272 HD patients and 141 controls completed the Tridimensional Personality Questionnaire to evaluate their personality traits. In addition, a further sample 303 HD patients and 204 controls was added (with totally 920 participants) for the gene association and genotype-phenotype interaction studies.

RESULTS

Patients with HD had higher novelty seeking (NS) and harm avoidance (HA) scores than healthy subjects. Nonetheless, NGF gene polymorphisms did not associate with specific personality traits in HD patients and controls. There is no significant difference in NGF gene polymorphisms between patients with HD and controls.

DISCUSSION AND CONCLUSIONS

The NGF gene may neither contribute to the risk of development of HD, nor mediate the relationship between specific personality traits and HD in Han Chinese male population.

SCIENTIFIC SIGNIFICANCE

Patients with HD had higher novelty seeking (NS) and harm avoidance (HA) scores than healthy subjects. However, none of the polymorphisms in the NGF gene affected the NS and HA scores in both patients and healthy subjects. (Am J Addict 2018;27:516-523).

Effects of Acute and Chronic Restraint Stress on Reinstatement of Extinguished Methamphetamine-induced Conditioned Place Preference in Rats

Introduction:

Methamphetamine (METH) is a neurotoxic psychostimulant with highly addictive potential that leads to compulsive drug use and vulnerability to relapse. Environmental cues, such as drug exposure, peer influence, and social stress, are the powerful triggers of drug relapse. In this study, we tried to find out the effect of acute and chronic restraint stress on reinstatement of extinguished METH-induced Conditioned Place Preference (CPP) in rats.

Methods:

Subcutaneous (SC) administration of METH (0.125, 0.25, 0.5, 1, 2 and 4 mg/kg) could induce CPP and it was found that METH with the dose of 0.5 mg/kg was more potent than other doses. In extinction phase, rats were put in the CPP box for 30 min per day for 8 consecutive days. After extinction, animals were exposed to restraint stress (3-h period, as an acute stress) 60 min before subcutaneous administration of ineffective dose of METH (0.125 mg/kg) in order to reinstate the extinguished METH-induced CPP. For induction of the chronic stress during extinction phase, the animals were exposed to the restraint stress for one hour per day.

Results:

The results showed that the effective dose of METH to induce CPP was 0.5 mg/kg. Based on the results, physical stress (restraint stress) whether acute and chronic, can significantly induce reinstatement of METH-induced CPP (P˂0.001) in extinguished animals.

Conclusion:

Additionally, the chronic restraint stress could reduce duration of extinction (maintenance) of METH-induced CPP. It seems that exposure to the stress induces the relapse in abstinent amphetamine, but acute and chronic situation have a different reaction.

Impulsivity predicts poorer improvement in quality of life during early treatment for people with methamphetamine dependence

BACKGROUND AND AIMS

Methamphetamine dependence is associated with heightened impulsivity and diminished quality of life, but the link between impulsivity and changes in quality of life during treatment has not been examined. We aimed to investigate how different elements of impulsivity predict change in quality of life in the 6 weeks after engaging in treatment.

DESIGN

Longitudinal, observational cohort study.

SETTING

Public and private detoxification and rehabilitation facilities in metropolitan Melbourne, Australia.

PARTICIPANTS

One hundred and eight individuals with methamphetamine dependence (81 male) tested within 3 weeks of commencing treatment; 80 (74%) were followed-up at 6 weeks.

MEASUREMENTS

The Continuous Performance Test-2 measured impulsive action (cognitive and motor impulsivity); the Delay Discounting Task measured impulsive choice. Quality of life was measured with the World Health Organization Quality of Life Scale-Brief, which includes social, psychological, physical and environment domains. Control variables included age, gender, estimated IQ, depression severity score, methamphetamine dependence severity score, cannabis dependence severity score and treatment modality.

FINDINGS

We found that all three forms of impulsivity were significant predictors of change in the social domain: motor impulsivity (β = -0.54, P = 0.013), cognitive impulsivity (β = -0.46, P = 0.029) and impulsive choice (β = -0.26, P = 0.019). Change in the psychological domain was predicted significantly by motor impulsivity (β = -0.45, P = 0.046). Control variables of age and depression were associated significantly with changes in the physical domain.

CONCLUSIONS

In Australian methamphetamine-dependent individuals, elevated impulsivity predicts lower improvement of social and psychological quality of life in the first 6-9 weeks of treatment.

HIV-1 Proteins Influence Novelty-Seeking Behavior and Alter Region-Specific Transcriptional Responses to Chronic Nicotine Treatment in HIV-1Tg Rats

INTRODUCTION

Clinical studies suggest that HIV-1-infected patients are more likely to use or abuse addictive drugs than is the general population. We hypothesized that HIV-1 proteins impact novelty-seeking behavior and enhance the transcriptional response to nicotine in genes implicated in both novelty-seeking behavior and drug addiction.

METHODS

We assessed the effects of HIV-1 proteins on novelty-seeking behavior by comparing baseline activity differences of HIV-1Tg and F344 control rats in the open-field test. One day after behavioral testing, all rats began daily subcutaneous injections of either nicotine (0.4 mg/kg, base) or saline (the same for each rat) for 27 days. At the end of treatment, the prefrontal cortex, nucleus accumbens, and ventral tegmental area were collected for RNA expression analysis of genes in the receptor families for dopamine, GABA, glutamate, and serotonin.

RESULTS

Significant strain difference was detected in the distance moved in the center, such that HIV-1Tg rats traveled greater distance in the center of the arena than did F344 rats. Quantitative RT-PCR analysis showed that mRNA from Drd3 and Grm2 in the prefrontal cortex and Drd5 and Gabra6 in the ventral tegmental area was significantly upregulated, whereas that of Drd5 in the nucleus accumbens was downregulated in HIV-1Tg rats compared with F344 rats. Further, more addiction-related genes were significantly modulated by nicotine in each brain region in the HIV-1Tg rats than in the control animals.

CONCLUSIONS

HIV-1 proteins may affect novelty-seeking behavior and modulate the expression of genes related to drug addiction and novelty-seeking behavior.

IMPLICATIONS

HIV-1 viral proteins and chronic nicotine treatment impact the expression of genes involved in novelty-seeking behavior and addiction in three brain regions of the HIV-1 transgenic rat. These findings implicate that HIV-1 proteins may be involved in novelty-seeking behavior and in modulating the expression of genes related to drug addiction and novelty seeking.

Evaluation of coping as a mediator of the relationship between stressful life events and cancer-related distress

OBJECTIVE

Lifetime stressful life events (SLEs) may predispose oncology patients to cancer-related distress (i.e., intrusive thoughts, hyperarousal, avoidance). Coping may influence cancer-related distress by mediating this relationship. This study sought to (a) determine the prevalence and impact of lifetime SLEs among oncology outpatients receiving chemotherapy and (b) examine the relationship between SLEs and cancer-related distress and the mediating role of coping on this relationship.

METHOD

Patients (n = 957), with breast, gastrointestinal, gynecologic or lung cancer, who were undergoing chemotherapy, completed the Life Stressor Checklist-Revised (LSC-R), a measure of lifetime SLEs. Cancer-related distress was assessed with the Impact of Event Scale-Revised. Coping strategies since beginning chemotherapy were assessed with the Brief COPE; 2 latent variables (engagement and disengagement coping) were identified based on these scores. LSC-R scores (number of SLEs and perceived impact during the prior year) were evaluated in relation to demographic and clinical characteristics. Structural equation modeling was used to evaluate the relationship between LSC-R and Impact of Event Scale-Revised scores and the mediating role of engagement and disengagement coping on this relationship.

RESULTS

On average, patients reported 6.1 (SD = 4.0; range = 0-23 out of 30) SLEs. Patients who were not married/partnered, had incomes <$30,000/year, or who had lower functional status or greater comorbidity had higher LSC-R scores. The relationship between more SLEs and more severe cancer-related distress was completely mediated by disengagement coping. Engagement coping did not mediate this relationship.

CONCLUSIONS

Disengagement coping, including behavioral disengagement, avoidance, and denial, should be targeted to mitigate cancer-related distress. (PsycINFO Database Record

Voluntary physical exercise protects against behavioral and endocrine reactivity to social and environmental stressors in the prairie vole

Physical activity can combat detrimental effects of stress. The current study examined the potential protective effects of exercise against a combination of social isolation and chronic mild stress (CMS) in a prairie vole model. Female voles were isolated for 4 weeks, with the addition of CMS during the final 2 weeks. Half of the voles were allowed access to a running wheel during this final 2 weeks, while the other half remained sedentary. Animals underwent behavioral tests to assess depressive- and anxiety-behaviors. In a subset of animals, plasma was collected 10 minutes after behavioral testing for corticosterone analysis. In a separate subset, brains were collected 2 hours after behavioral testing for cFos analysis in the paraventricular nucleus (PVN). Voles in the exercise group displayed significantly lower depressive- and anxiety-behaviors, and displayed significantly lower corticosterone levels, compared to animals in the sedentary group. There was no difference in PVN cFos activity between groups. Interestingly, animals that moderately exercised displayed lower levels of depressive-behavior and attenuated corticosterone reactivity compared to animals in the low and high activity subgroups. These findings suggest that physical activity can protect against a combination of social and environmental stressors.

Methamphetamine Use and Emergency Department Utilization: 20 Years Later

Background

Methamphetamine (MAP) users present to the emergency department (ED) for myriad reasons, including trauma, chest pain, and psychosis. The purpose of this study is to determine how their prevalence, demographics, and resource utilization have changed.

Methods

Retrospective review of MAP patients over 3 months in 2016. Demographics, mode of arrival, presenting complaints, disposition, and concomitant cocaine/ethanol use were compared to a 1996 study at the same ED.

Results

638 MAP-positive patients, 3,013 toxicology screens, and 20,203 ED visits represented an increase in prevalence compared to 1996: 461 MAP-positive patients, 3,102 screens, and 32,156 visits. MAP patients were older compared to the past. Mode of arrival was most frequently by ambulance but at a lower proportion than 1996, as was the proportion of MAP patients with positive cocaine toxicology screens and ethanol coingestion. Admission rate was lower compared to the past, as was discharge to jail. The proportion of MAP patients presenting with blunt trauma was lower compared to the past and higher for chest pain.

Conclusion

A significant increase in the prevalence of MAP-positive patients was found. Differences in presenting complaints and resource utilization may reflect the shifting demographics of MAP users, as highlighted by an older patient population relative to the past.

Quantifying absolute glutamate concentrations in nucleus accumbens of prescription opioid addicts by using 1H MRS

INTRODUCTION

The diagnosis of psychoactive substance use disorders has been based primarily on descriptive, symptomatic checklist criteria. In opioid addiction, there are no objective biological indicators specific enough to guide diagnosis, monitor disease status, and evaluate efficacy of therapeutic interventions. Proton magnetic resonance spectroscopy (¹H MRS) of the brain has potential to identify and quantify biomarkers for the diagnosis of opioid dependence. The purpose of this study was to detect the absolute glutamate concentration in the nucleus accumbens (NAc) of patients with prescription opioid dependence using ¹H MRS, and to analyze its clinical associations.

METHODS

Twenty patients with clinically diagnosed definitive prescription opioid dependent (mean age = 26.5 ± 4.3 years) and 20 matched healthy controls (mean age = 26.1 ± 3.8 years) participated in this study. Patients were evaluated with the Barratt Impulsiveness Scale (BIS-11), the Self-Rating Anxiety Scale (SAS), and the opiate Addiction Severity Inventory (ASI). We used point-resolved spectroscopy to quantify the absolute concentrations of metabolites (glutamate, choline, N-acetylaspartate, glutamine, creatine) within the NAc. The difference between metabolite levels of groups and Pearson's correlation between glutamate levels and psychometric scores in patients were analyzed statistically.

RESULTS

Glutamate concentrations in the NAc were significantly higher in prescription opiate addicts than in controls (t = 3.84, p = .001). None of the other metabolites differed significantly between the two groups (all ps > .05). The glutamate concentrations correlated positively with BIS-11 scores in prescription opiate addicts (r = .671, p = .001), but not with SAS score and ASI index.

CONCLUSIONS

Glutamate levels in the NAc measured quantitatively with in vivo ¹H MRS could be used as a biomarker to evaluate disease condition in opioid-dependent patients.

A pathway linking reward circuitry, impulsive sensation-seeking and risky decision-making in young adults: identifying neural markers for new interventions

High trait impulsive sensation seeking (ISS) is common in 18-25-year olds, and is associated with risky decision-making and deleterious outcomes. We examined relationships among: activity in reward regions previously associated with ISS during an ISS-relevant context, uncertain reward expectancy (RE), using fMRI; ISS impulsivity and sensation-seeking subcomponents; and risky decision-making in 100, transdiagnostically recruited 18-25-year olds. ISS, anhedonia, anxiety, depression and mania were measured using self-report scales; clinician-administered scales also assessed the latter four. A post-scan risky decision-making task measured 'risky' (possible win/loss/mixed/neutral) fMRI-task versus 'sure thing' stimuli. 'Bias' reflected risky over safe choices. Uncertain RE-related activity in left ventrolateral prefrontal cortex and bilateral ventral striatum was positively associated with an ISS composite score, comprising impulsivity and sensation-seeking-fun-seeking subcomponents (ISSc; P⩽0.001). Bias positively associated with sensation seeking-experience seeking (ES; P=0.003). This relationship was moderated by ISSc (P=0.009): it was evident only in high ISSc individuals. Whole-brain analyses showed a positive relationship between: uncertain RE-related left ventrolateral prefrontal cortical activity and ISSc; uncertain RE-related visual attention and motor preparation neural network activity and ES; and uncertain RE-related dorsal anterior cingulate cortical activity and bias, specifically in high ISSc participants (all ps<0.05, peak-level, family-wise error corrected). We identify an indirect pathway linking greater levels of uncertain RE-related activity in reward, visual attention and motor networks with greater risky decision-making, via positive relationships with impulsivity, fun seeking and ES. These objective neural markers of high ISS can guide new treatment developments for young adults with high levels of this debilitating personality trait.

Parallel Effects of Methamphetamine on Anxiety and CCL3 in Humans and a Genetic Mouse Model of High Methamphetamine Intake

BACKGROUND

Methamphetamine (MA) abuse causes immune dysfunction and neuropsychiatric impairment. The mechanisms underlying these deficits remain unidentified.

METHODS

The effects of MA on anxiety-like behavior and immune function were investigated in mice selectively bred to voluntarily consume high amounts of MA [i.e., MA high drinking (MAHDR) mice]. MA (or saline) was administered to mice using a chronic (14-day), binge-like model. Performance in the elevated zero maze (EZM) was determined 5 days after the last MA dose to examine anxiety-like behavior. Cytokine and chemokine expressions were measured in the hippocampus using quantitative polymerase chain reaction (qPCR). Human studies were also conducted to evaluate symptoms of anxiety using the General Anxiety Disorder-7 Scale in adults with and without a history of MA dependence. Plasma samples collected from human research participants were used for confirmatory analysis of murine qPCR results using an enzyme-linked immunosorbent assay.

RESULTS

During early remission from MA, MAHDR mice exhibited increased anxiety-like behavior on the EZM and reduced expression of chemokine (C-C motif) ligand 3 (ccl3) in the hippocampus relative to saline-treated mice. Human adults actively dependent on MA and those in early remission had elevated symptoms of anxiety as well as reductions in plasma levels of CCL3, relative to adults with no history of MA abuse.

CONCLUSIONS

The results highlight the complex effects of MA on immune and behavioral function and suggest that alterations in CCL3 signaling may contribute to the mood impairments observed during remission from MA addiction.

Comorbid trajectories of substance use as predictors of Antisocial Personality Disorder, Major Depressive Episode, and Generalized Anxiety Disorder

OBJECTIVE

To determine longitudinal associations between patterns of comorbid cigarette, alcohol, and marijuana use and Antisocial Personality Disorder (ASPD), Major Depressive Episode (MDE), and Generalized Anxiety Disorder (GAD) in adulthood.

METHOD

A random community-based sample [X̅ age=36.6 (SD=2.8)] from the Children and Adults in the Community Study, an on-going investigation of substance use and psychiatric disorders. Data were collected at six time waves. Conjoint trajectories of cigarette, alcohol, and marijuana use spanning adolescence to adulthood were determined; multivariable logistic regression analyses assessed associations between trajectory group membership and having ASPD, MDE, or GAD in adulthood.

RESULTS

Five conjoint trajectory groups were obtained: HHH (chronic cigarette, alcohol, and marijuana use), DDD (delayed/late-starting cigarette, alcohol, and marijuana use), LML (low/no smoking, moderate alcohol use, occasional marijuana use), HMN (chronic smoking, moderate alcohol use, no marijuana use), and NON (occasional alcohol use only). Compared with members of the NON group, those in the HHH group had significantly greater odds for having ASPD (Adjusted Odds Ratio [AOR]=28.52, 95% Confidence Interval [CI]=9.44-86.17), MDE (AOR=2.67, 95% CI=1.14-6.26), and GAD (AOR=6.39, 95% CI=2.62-15.56). Members of the DDD, LML, and HMN groups had weaker and less consistent associations with the three psychiatric outcomes.

CONCLUSIONS

In a large, community-based sample, long-term concurrent use of more than one substance was associated with both externalizing and internalizing psychiatric disorders in adulthood. Prevention and treatment programs might target individuals in the community and general clinical populations with comorbid substance use, even if they haven't been identified as having a substance use disorder.

Prevalence of driving under the influence of psychoactive substances and road traffic crashes among Brazilian crack-using drivers

BACKGROUND

Substance use disorders are associated with the increased risk of driving under the influence (DUI), but little is known about crack-cocaine and its relationship with road traffic crashes (RTC).

METHOD

A multicenter sample of 765 crack-cocaine users was recruited in six Brazilian capitals in order to estimate the prevalence of DUI and RTC involvement. Legal, psychiatric, and drug-use aspects related with traffic safety were evaluated using the Addiction Severity Index - 6th version (ASI-6) and the Mini International Neuropsychiatric Interview.

RESULTS

Seventy-six (28.3%) current drivers reported accident involvement following crack-cocaine use. Among drivers (n=269), 45.7% and 30.5% reported DUIs in the past 6 months and 30 days, respectively. Drivers reporting DUI's in the past month (n=82) had higher scores in the "psychiatric", "legal", and "family problems" subscales from the ASI-6, and lower scores in the "family social support" subscale in comparison to those without a history of DUIs (n=187). An overall high prevalence of psychiatric comorbidity and substance consumption was observed. Participants with 5+ years of crack-cocaine use were more likely to have been in a RTC (RR=1.52, 95%IC: 1.02-2.75), independently of marijuana use, binge drinking and psychiatric comorbidities.

CONCLUSION

The high prevalence of RTC and DUI involvement among crack-using drivers supports the idea that they are at a high risk group regarding traffic safety. Years of crack consumption seem to be associated with RTC involvement. Also, the presence of psychiatric comorbidities, poly-drug use, and cognitive impairment usually associated with crack addiction could yield additional risk of accidents.

Novelty Seeking and Drug Addiction in Humans and Animals: From Behavior to Molecules

Global treatment of drug addiction costs society billions of dollars annually, but current psychopharmacological therapies have not been successful at desired rates. The increasing number of individuals suffering from substance abuse has turned attention to what makes some people more vulnerable to drug addiction than others. One personality trait that stands out as a contributing factor is novelty seeking. Novelty seeking, affected by both genetic and environmental factors, is defined as the tendency to desire novel stimuli and environments. It can be measured in humans through questionnaires and in rodents using behavioral tasks. On the behavioral level, both human and rodent studies demonstrate that high novelty seeking can predict the initiation of drug use and a transition to compulsive drug use and create a propensity to relapse. These predictions are valid for several drugs of abuse, such as alcohol, nicotine, cocaine, amphetamine, and opiates. On the molecular level, both novelty seeking and addiction are modulated by the central reward system in the brain. Dopamine is the primary neurotransmitter involved in the overlapping neural substrates of both parameters. In sum, the novelty-seeking trait can be valuable for predicting individual vulnerability to drug addiction and for generating successful treatment for patients with substance abuse disorders.

Psychological intervention with working memory training increases basal ganglia volume: A VBM study of inpatient treatment for methamphetamine use

BACKGROUND

Protracted methamphetamine (MA) use is associated with decreased control over drug craving and altered brain volume in the frontostriatal network. However, the nature of volumetric changes following a course of psychological intervention for MA use is not yet known.

METHODS

66 males (41 MA patients, 25 healthy controls, HC) between the ages of 18-50 were recruited, the MA patients from new admissions to an in-patient drug rehabilitation centre and the HC via public advertisement, both in Cape Town, South Africa. 17 MA patients received 4 weeks of treatment as usual (TAU), and 24 MA patients completed TAU plus daily 30-minute cognitive training (CT) using an N-back working memory task. Magnetic resonance imaging (MRI) at baseline and 4-week follow-up was acquired and voxel-based morphometry (VBM) was used for analysis.

RESULTS

TAU was associated with larger bilateral striatum (caudate/putamen) volume, whereas CT was associated with more widespread increases of the bilateral basal ganglia (incorporating the amygdala and hippocampus) and reduced bilateral cerebellum volume coinciding with improvements in impulsivity scores.

CONCLUSIONS

While psychological intervention is associated with larger volume in mesolimbic reward regions, the utilisation of additional working memory training as an adjunct to treatment may further normalize frontostriatal structure and function.

The effects of oral d-amphetamine on impulsivity in smoked and intranasal cocaine users

BACKGROUND

Effective treatments for cocaine use disorders remain elusive. Two factors that may be related to treatment failures are route of cocaine used and impulsivity. Smoked cocaine users are more likely to have poorer treatment outcomes compared to intranasal cocaine users. Further, cocaine users are impulsive and impulsivity is associated with poor treatment outcomes. While stimulants are used to treat Attention Deficit Hyperactivity Disorder (ADHD) and attenuate certain cocaine-related behaviors, few studies have comprehensively examined whether stimulants can reduce behavioral impulsivity in cocaine users, and none examined route of cocaine use as a factor.

METHODS

The effects of immediate release oral d-amphetamine (AMPH) were examined in 34 cocaine users (13 intranasal, 21 smoked). Participants had three separate sessions where they were administered AMPH (0, 10, or 20mg) and completed behavioral measures of impulsivity and risk-taking and subjective measures of abuse liability.

RESULTS

Smoked cocaine users were more impulsive on the Delayed Memory Task, the GoStop task and the Delay Discounting Task than intranasal cocaine users. Smoked cocaine users also reported more cocaine craving and negative mood than intranasal cocaine users. AMPH produced minimal increases on measures of abuse liability (e.g., Drug Liking).

CONCLUSIONS

Smoked cocaine users were more impulsive than intranasal cocaine users on measures of impulsivity that had a delay component. Additionally, although AMPH failed to attenuate impulsive responding, there was minimal evidence of abuse liability in cocaine users. These preliminary findings need to be confirmed in larger samples that control for route and duration of cocaine use.

Chronic variable stress and intravenous methamphetamine self-administration - Role of individual differences in behavioral and physiological reactivity to novelty

Stress is a contributing factor to the development and maintenance of addiction in humans. However, few studies have shown that stress potentiates the rewarding and/or reinforcing effects of methamphetamine in rodent models of addiction. The present study assessed the effects of exposure to 14 days of chronic variable stress (CVS), or no stress as a control (CON), on the rewarding and reinforcing effects of methamphetamine in adult rats using the conditioned place preference (Experiment 1) and intravenous self-administration (Experiment 2) paradigms. In Experiment 2, we also assessed individual differences in open field locomotor activity, anxiety-like behavior in the elevated plus maze (EPM), and physiological responses to a novel environment as possible predictors of methamphetamine intake patterns. Exposure to CVS for 14 days did not affect overall measures of methamphetamine conditioned reward or reinforcement. However, analyses of individual differences and direct vs. indirect effects revealed that rats exhibiting high physiological reactivity and locomotor activity in the EPM and open field tests self-administered more methamphetamine and reached higher breakpoints for drug reinforcement than rats exhibiting low reactivity. In addition, CVS exposure significantly increased the proportion of rats that exhibited high reactivity, and high reactivity was significantly correlated with increased levels of methamphetamine intake. These findings suggest that individual differences in physiological and locomotor reactivity to novel environments, as well as their interactions with stress history, predict patterns of drug intake in rodent models of methamphetamine addiction. Such predictors may eventually inform future strategies for implementing individualized treatment strategies for amphetamine use disorders.

Brain Microstructure and Impulsivity Differ between Current and Past Methamphetamine Users

Methamphetamine (Meth) use disorder continues to be highly prevalent worldwide. Meth users have higher impulsivity and brain abnormalities that may be different between current and past Meth users. The current study assessed impulsivity and depressive symptoms in 94 participants (27 current Meth users, 32 past Meth users and 35 non-drug user controls). Additionally, brain microstructure was assessed using diffusion tensor imaging (DTI); fractional anisotropy (FA) and mean diffusivity (MD) were assessed in the striatum, and FA, MD, radial and axial diffusivity were quantified in five white matter structures using DtiStudio.Across the three subject groups, current users had the highest self-reported impulsivity scores, while both Meth user groups had larger striatal structures than the controls. Past Meth users had the highest FA and lowest MD in the striatum, which is likely due to greater magnetic susceptibility from higher iron content and greater dendritic spine density. In white matter tracts, current Meth users had higher AD than past users, indicating greater water diffusion along the axons, and suggesting inflammation with axonal swelling. In contrast, past users had the lowest AD, indicating more restricted diffusion, which might have resulted from reactive gliosis. Although current Meth users had greater impulsivity than past users, the brain microstructural abnormalities showed differences that may reflect different stages of neuroinflammation or iron-induced neurodegeneration. Combining current and past Meth users may lead to greater variability in studies of Meth users. Longitudinal studies are needed to further evaluate the relationship between recency of Meth use and brain microstructure.