Stress-induced changes in mood and cortisol release predict mood effects of amphetamine

Stimulant Treatment and Potential Adverse Outcomes in Pediatric Populations With Bipolar Disorder: A Systematic Review of the Literature

OBJECTIVE

To explore outcomes of stimulant treatment for ADHD in pediatric populations with particular attention to bipolar disorder (BPD).

METHOD

We conducted a literature search of PubMed articles published prior to August 25, 2022 that focused on BPD, mania, and psychosis prior to, or as result of, stimulant treatment. We excluded studies: (1) unrelated to stimulants, (2) general stimulant research, (3) articles older than 40 years, (4) study protocols, or (5) case reports.

RESULTS

A total of 11 articles met all inclusion/exclusion criteria. Some reports found stimulant treatment safe and well-tolerated in children with comorbid BPD and ADHD. Others found evidence of treatment-emergent mania (TEM), discontinuation, and other adverse events with stimulant treatment.

CONCLUSION

Poor outcomes associated with stimulant treatment in pediatric populations with BPD necessitate work to identify patients at risk of serious stimulant-related adverse events. Our results were limited by automated search filters and a pediatric, primarily male sample.

Green Spaces with Fewer People Improve Self-Reported Affective Experience and Mood

Calm and quiet green spaces provide health benefits for urban residents. Yet as cities become more densely populated, increasing public users to green spaces may reduce or moderate these benefits. We examine how increased pedestrian density in a green street changes self-reported wellbeing. We use a between subject experimental design that added public users as confederates in randomly selected periods over three weeks. We collect data on mood and affective response from pedestrians moving through the green street (n = 504), with and without our public user treatment in randomly selected periods. Mood and affective response are improved when experiencing the green street with fewer people. We find that an increased number of public users in the green space has a negative effect on mood, especially among women. We provide experimental evidence that self-reported wellbeing in urban green spaces depends on social context, and that there are gender inequities associated with changes in affective response. Although we only measure immediate impacts, our results imply that the health benefits of green spaces may be limited by the total number of users. This research contributes additional evidence that greener cities are also healthier cities, but that the benefits may not be equally shared between women and men and will depend on the social context of use.

Methamphetamine, amphetamine, and aggression in humans: A systematic review of drug administration studies

The relationship between amphetamine use and aggressive or violent behaviour is unclear. This review examined laboratory data collected in humans, who were administered an acute dose of amphetamine or methamphetamine, in order to investigate the link between amphetamines and aggression. It is registered with PROSPERO (CRD42019127711). Included in the analysis are data from twenty-eight studies. Behavioural and/or subjective measures of aggression were assessed in one thousand and sixty-nine research participants, with limited amphetamine-use histories, following a single amphetamine dose (0-35mg). The available published evidence indicates that neither amphetamine nor methamphetamine acutely increased aggression as assessed by traditional laboratory measures. Future research should assess supratherapeutic amphetamine doses as well as include a broader range of multiple aggression measures, facilitating simultaneous assessment of the various components that comprise this complex, multifaceted construct.

Treatment-induced mood switching in affective disorders

Many patients under treatment for mood disorders, in particular patients with bipolar mood disorders, experience episodes of mood switching from one state to another. Various hypotheses have been proposed to explain the mechanism of mood switching, spontaneously or induced by drug treatment. Animal models have also been used to test the role of psychotropic drugs in the switching of mood states. We examine the possible relationship between the pharmacology of psychotropic drugs and their reported incidents of induced mood switching, with reference to the various hypotheses of mechanisms of mood switching.

Acute exposure to N-Ethylpentylone induces developmental toxicity and dopaminergic receptor-regulated aberrances in zebrafish larvae

N-Ethylpentylone (NEP) is one of the most recent novel stimulants, and there is limited understanding of its toxicity. Here we employed zebrafish model for analyzing the effects of NEP on early embryos and cardiovascular and nervous systems at late developmental stages. We first observed multi-malformations in early embryos and larvae after NEP administration, together with significant deregulations of brain and heart development-associated genes (neurog1, her6, elavl3, nkx2.5, nppa, nppb, tnnt2a) at transcriptional level. Low-dosed NEP treatment induced an anxiety-like phenotype in zebrafish larvae, while higher doses of NEP exerted an inhibitory effect on locomotion and heart rate. Besides, the expression of th (tyrosine hydroxylase) and th2 (tyrosine hydroxylase 2), identifying dopamine (DA) release, were significantly increased during one-hour free swimming after effective low-dosed NEP administration, along with the upregulation of gene fosab and fosb related to stress and anxiety response. D1R antagonist SCH23390 and D2R antagonist sulpiride partially alleviated the aberrances of locomotion and heart rate, indicating dopaminergic receptors were involved in the bidirectional dosage-dependent pattern of NEP-induced performance. Meanwhile, sulpiride offset the upregulated expression of th, th2 and fosab in the group of 1.5 μM NEP, which highlighted the significant role of D2R in NEP-induced locomotive effects. This study systematically described the developmental, neuronal and cardiac toxicity of NEP in zebrafish, and identified the dopaminergic receptors as one of the downstream effectors of NEP administration.

Correlates of nonmedical use of prescription opioids among a cohort of adolescents in Ontario, Canada

INTRODUCTION

Mortality and morbidity rates related to prescription opioid analgesics have been rising in North America and may be a gateway to the nonmedical use of prescription opioids (NUPO). The purpose of this study was to explore correlates of NUPO in the adolescent population given the scarce literature in this area.

METHODS

Cross-sectional data from 10,163 middle- and high-school students (15.1 ± 1.8 years old; 57.0% female; 55.6% White ethnic background) in Ontario were derived from the 2017 Ontario Student Drug Use and Health Survey. Potential correlates of NUPO in the past year included sociodemographic, behavioral, parental, and school characteristics.

RESULTS

Overall prevalence of NUPO was 10.7%. In the final multivariable model, NUPO was significantly associated with 8 of the 21 correlates examined. Students who used prescription opioids nonmedically were of black, South Asian, and "other" ethnic backgrounds (OR 2.83, OR 1.77, and OR 1.67, respectively); reported a lower subjective socioeconomic status (OR 0.92), lower parental support (OR 0.90), and lower academic performance (OR 0.86); met physical activity recommendations (OR 1.48); consumed energy drinks (OR 1.42); smoked tobacco cigarettes (OR 2.33); and used cannabis (OR 1.84).

CONCLUSIONS

Findings from this study show a wide variety of correlates of NUPO among Canadian adolescents, and highlight the need for further research and the value in targeted prevention and multi-level intervention programs for NUPO in this population.

Psychotropic medication effects on cortisol: Implications for research and mechanisms of drug action

Stress and the hypothalamic-pituitary-adrenal (HPA) axis have been implicated in the etiology of a range psychiatric disorders; abnormalities in cortisol secretion are well documented in mood, anxiety, and psychotic disorders. There is, however, evidence that psychotropic medications affect HPA function, and are often a confound in research on the relation of cortisol secretion with psychiatric symptoms and syndromes. Psychotropic effects are particularly problematic in longitudinal research on individuals at clinical high risk (CHR) for serious mental illness, because they have the potential to obscure neurobiological mechanisms involved in crossing the threshold from CHR states to clinical disorders. This paper reviews the research literature on the relation of cortisol secretion with the three major classes of psychotropic medication that are most often prescribed; antipsychotics, antidepressants, and stimulants. The studies included in this review are those that measured both baseline and post-treatment cortisol. Taken together, most studies of antidepressants find that they are associated with a reduction in both basal and post-dexamethasone-CRH (DEX/CRH) cortisol, although some report no change. Similarly, antipsychotics, both typical and atypical, are found to reduce basal and DEX/CRH cortisol levels in most studies. Psychostimulant medications, in contrast, are associated with an increase in basal cortisol levels or no change. Effects of psychotropics on the cortisol awakening response (CAR) are less consistent. Implications of these effects for clinical research, especially studies of CHR populations, are discussed. Limitations of the research, due to variations in sample demographic and methodologic factors, are noted, and directions for future research are proposed.

Stress changes amphetamine response, D2 receptor expression and epigenetic regulation in low-anxiety rats

The aim of this study was to assess the influence of chronic restraint stress on amphetamine (AMPH)-related appetitive 50-kHz ultrasonic vocalisations (USVs) in rats differing in freezing duration in a contextual fear test (CFT), i.e. HR (high-anxiety responsive) and LR (low-anxiety responsive) rats. The LR and the HR rats, previously exposed to an AMPH binge experience, differed in sensitivity to AMPH's rewarding effects, measured as appetitive vocalisations. Moreover, chronic restraint stress attenuated AMPH-related appetitive vocalisations in the LR rats but had no influence on the HR rats' behaviour. To specify, the restraint LR rats vocalised appetitively less in the AMPH-associated context and after an AMPH challenge than the control LR rats. This phenomenon was associated with a decrease in the mRNA level for D2 dopamine receptor in the amygdala and its protein expression in the basal amygdala (BA) and opposite changes in the nucleus accumbens (NAc) - an increase in the mRNA level for D2 dopamine receptor and its protein expression in the NAc shell, compared to control conditions. Moreover, we observed that chronic restraint stress influenced epigenetic regulation in the LR and the HR rats differently. The contrasting changes were observed in the dentate gyrus (DG) of the hippocampus - the LR rats presented a decrease, but the HR rats showed an increase in H3K9 trimethylation. The restraint LR rats also showed higher miR-494 and miR-34c levels in the NAc than the control LR group. Our study provides behavioural and biochemical data concerning the role of differences in fear-conditioned response in stress vulnerability and AMPH-associated appetitive behaviour. The LR rats were less sensitive to the rewarding effects of AMPH when previously exposed to chronic stress that was accompanied by changes in D2 dopamine receptor expression and epigenetic regulation in mesolimbic areas.

Drug-induced stress responses and addiction risk and relapse

A number of studies have assessed the effects of psychoactive drugs on stress biology, the neuroadaptations resulting from chronic drug use on stress biology, and their effects on addiction risk and relapse. This review mainly covers human research on the acute effects of different drugs of abuse (i.e., nicotine, cannabis, psychostimulants, alcohol, and opioids) on the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) responses. We review the literature on acute peripheral stress responses in naïve or light recreational users and binge/heavy or chronic drug users. We also discuss evidence of alterations in tonic levels, or tolerance, in the latter relative to the former and associated changes in the phasic stress responses. We discuss the impact of the stress system tolerance in heavy users on their response to drug- and stress-related cue responses and craving as compared to control subjects. A summary is provided of the effects of glucocorticoid responses and their adaptations on brain striatal and prefrontal cortices involved in the regulation of drug seeking and relapse risk. Finally, we summarize important considerations, including individual difference factors such as gender, co-occurring drug use, early trauma and adversity and drug use history and variation in methodologies, that may further influence the effects of these drugs on stress biology.

Anger, anxiety, and depressive affect as predictors of stress-induced cortisol production in khat and tobacco users

INTRODUCTION

Glucocorticoid activity is disrupted in substance users including khat chewers who also use tobacco. Anger, dysphoria, and anxiety can mediate this relationship. The aim of this study was to contrast emotion dysregulation and substance use variables as predictors of post-stress cortisol output.

MATERIALS AND METHODS

Comparable numbers of males (n = 90) and females (n = 85) including controls, khat only, and concurrent khat and tobacco users participated in a stress study. Depressive affect, anxiety, anger, substance use patterns, and saliva samples were collected following a standardized laboratory stress manipulation.

RESULTS

Regression analysis showed that high depression and low anxiety was associated with high post-stress cortisol, but only in co-users of tobacco and khat. Males, but not females, showed a significant association between co-use of khat and tobacco and cortisol, which appears to be mediated by frequency of use. The link between anxiety and post-stress cortisol in the co-users remained significant after controlling for nicotine dependence and substance use frequency.

CONCLUSION

Anxiety predicted the neuroendocrine consequences of concurrent use of tobacco and khat above and beyond sex, nicotine dependence, anger, and substance use frequency. Sex differences, however, are related to differences in nicotine dependence.

Salivary cortisol and α-amylase: subclinical indicators of stress as cardiometabolic risk

Currently, the potential for cardiovascular (CV) stress-induced risk is primarily based on the theoretical (obvious) side effects of stress on the CV system. Salivary cortisol and α-amylase, produced respectively by the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic-adrenomedullary (SAM) system during stress response, are still not included in the routine evaluation of CV risk and require additional and definitive validation. Therefore, this article overviews studies published between 2010 and 2015, in which salivary cortisol and α-amylase were measured as stress biomarkers to examine their associations with CV/CMR (cardiometabolic risk) clinical and subclinical indicators. A comprehensive search of PubMed, Web of Science and Scopus electronic databases was performed, and 54 key articles related to the use of salivary cortisol and α-amylase as subclinical indicators of stress and CV/CMR factors, including studies that emphasized methodological biases that could influence the accuracy of study outcomes, were ultimately identified. Overall, the biological impact of stress measured by salivary cortisol and α-amylase was associated with CV/CMR factors. Results supported the use of salivary cortisol and α-amylase as potential diagnostic tools for detecting stress-induced cardiac diseases and especially to describe the mechanisms by which stress potentially contributes to the pathogenesis and outcomes of CV diseases.

Maladaptive choices by defeated rats: link between rapid approach to social threat and escalated cocaine self-administration

RATIONALE

Intermittent social defeat stress engenders persistent neuroadaptations and can result in later increased cocaine taking and seeking. However, there are individual differences in stress-escalated cocaine self-administration behavior, which may be a direct result of individual differences in the manner in which rats experience social defeat stress.

OBJECTIVE

The present study dissected the discrete behavioral phases of social defeat and analyzed which behavioral characteristics may be predictive of subsequent cocaine self-administration.

METHODS

Male Long-Evans rats underwent nine intermittent social defeat episodes over 21 days in a three-compartment apparatus permitting approach to and escape from a confrontation with an aggressive resident rat. Rats then self-administered intravenous cocaine, which culminated in a 24-h unlimited access "binge." Behaviors during social defeat and cocaine self-administration were evaluated by principal component analysis (PCA).

RESULTS

PCA revealed that the latency to enter the threatening environment was highly predictive of later cocaine self-administration during the 24-h binge. This behavior was not associated with other cocaine-predictive traits, such as reactivity to novelty in an open field, saccharin preference, and motor impulsivity. Additionally, there was no effect of latency to enter a threatening environment on physiological measures of stress, including plasma corticosterone and corticotropin releasing factor (CRF) in the extended amygdala. However, latency to enter the threatening environment was negatively correlated with brain-derived neurotropic factor (BDNF) and its receptor, tyrosine kinase B (TrkB) in the hippocampus.

CONCLUSION

These data suggest that latency to enter a threatening environment is a novel behavioral characteristic predictive of later cocaine self-administration.

Acute Effects of Lysergic Acid Diethylamide on Circulating Steroid Levels in Healthy Subjects

Lysergic acid diethylamide (LSD) is a serotonin 5-hydroxytryptamine-2A (5-HT2A ) receptor agonist that is used recreationally worldwide. Interest in LSD research in humans waned after the 1970s, although the use of LSD in psychiatric research and practice has recently gained increasing attention. LSD produces pronounced acute psychedelic effects, although its influence on plasma steroid levels over time has not yet been characterised in humans. The effects of LSD (200 μg) or placebo on plasma steroid levels were investigated in 16 healthy subjects using a randomised, double-blind, placebo-controlled, cross-over study design. Plasma concentration-time profiles were determined for 15 steroids using liquid-chromatography tandem mass-spectrometry. LSD increased plasma concentrations of the glucocorticoids cortisol, cortisone, corticosterone and 11-dehydrocorticosterone compared to placebo. The mean maximum concentration of LSD was reached at 1.7 h. Mean peak psychedelic effects were reached at 2.4 h, with significant alterations in mental state from 0.5 h to > 10 h. Mean maximal concentrations of cortisol and corticosterone were reached at 2.5 h and 1.9 h, and significant elevations were observed 1.5-6 h and 1-3 h after drug administration, respectively. LSD also significantly increased plasma concentrations of the androgen dehydroepiandrosterone but not other androgens, progestogens or mineralocorticoids compared to placebo. A close relationship was found between plasma LSD concentrations and changes in plasma cortisol and corticosterone and the psychotropic response to LSD, and no clockwise hysteresis was observed. In conclusion, LSD produces significant acute effects on circulating steroids, especially glucocorticoids. LSD-induced changes in circulating glucocorticoids were associated with plasma LSD concentrations over time and showed no acute pharmacological tolerance.

Stress psychobiology in the context of addiction medicine: from drugs of abuse to behavioral addictions

In this chapter, we briefly review the basic biology of psychological stress and the stress response. We propose that psychological stress and the neurobiology of the stress response play in substance use initiation, maintenance, and relapse. The proposed mechanisms for this include, on the one hand, the complex interactions between biological mediators of the stress response and the dopaminergic reward system and, on the other hand, mediators of the stress response and other systems crucial in moderating key addiction-related behaviors such as endogenous opioids, the sympathetic-adrenal-medullary system, and endocannabinoids. Exciting new avenues of study including genomics, sex as a moderator of the stress response, and behavioral addictions (gambling, hypersexuality, dysfunctional internet use, and food as an addictive substance) are also briefly presented within the context of stress as a moderator of the addictive process.

Differential cardiovascular and hypothalamic pituitary response to amphetamine in male pathological gamblers versus healthy controls

Cardiovascular and hypothalamic pituitary axis (HPA) disturbances have been observed in individuals who are pathological gamblers (PGs). These may partly derive from chronic exposure to gambling. Response to amphetamine (AMPH) may reveal such disturbances while controlling for differential conditioned responses to gambling in PGs vs healthy controls (HCs). This study assessed heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) and plasma cortisol following oral AMPH (0.4 mg/kg) in male PGs (n=12) and HCs (n=11) who underwent a positron emission tomography (PET) scan. The Stop Signal Task enabled assessment of the link between physiological and behavioral dysregulation. Trait moderating effects were explored. The responses of PGs to AMPH differed from those of HCs on every index. PGs displayed persistent elevation in DBP and concomitant reduction in HR (i.e. baroreflex) compared to HCs beyond 90 min post-dose. PGs displayed deficits in cortisol compared to HCs that were partially reversed by AMPH. Impairment on the Stop Signal Task correlated positively with HR in controls, but negatively with HR in PGs, suggesting that strong initial and compensatory cardiac responses to a stimulant may each predict disinhibition. Extraversion predicted greater disinhibition in PGs. Noradrenergic disturbances may contribute to sensitized responses to stimulant challenge and disinhibition in PGs.

Personality traits modulate emotional and physiological responses to stress

An individual's susceptibility to psychological and physical disorders associated with chronic stress exposure, for example, cardiovascular and infectious disease, may also be predicted by their reactivity to acute stress. One factor associated with both stress resilience and health outcomes is personality. An understanding of how personality influences responses to acute stress may shed light upon individual differences in susceptibility to chronic stress-linked disease. This study examined the relationships between personality and acute responses to stress in 125 healthy adults, using hierarchical linear regression. We assessed personality traits using the Multidimensional Personality Questionnaire (MPQ-BF), and responses to acute stress (cortisol, heart rate, blood pressure, mood) using a standardized laboratory psychosocial stress task, the Trier Social Stress Test. Individuals with high Negative Emotionality exhibited greater emotional distress and lower blood pressure responses to the Trier Social Stress Test. Individuals with high agentic Positive Emotionality exhibited prolonged heart rate responses to stress, whereas those with high communal Positive Emotionality exhibited smaller cortisol and blood pressure responses. Separate personality traits differentially predicted emotional, cardiovascular, and cortisol responses to a psychosocial stressor in healthy volunteers. Future research investigating the association of personality with chronic stress-related disease may provide further clues to the relationship between acute stress reactivity and susceptibility to disease.

Total antioxidant capacity is significantly lower in cocaine-dependent and methamphetamine-dependent patients relative to normal controls: results from a preliminary study

BACKGROUND

Oxidative stress can result in damage to the brain and other organs. To protect from oxidative damage, the human body possesses molecular defense systems, based on the activity of antioxidants, and enzymatic defense systems, including the enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px). Although pre-clinical research has shown that stimulant use is associated with oxidative damage, oxidative stress and the antioxidant defense systems have not been evaluated in clinical samples of stimulant-dependent patients.

OBJECTIVES

This study aimed to investigate the link between stimulant dependence and oxidative stress.

METHODS

Peripheral blood samples from 174 methamphetamine (n = 48) and/or cocaine-dependent (n = 126) participants as well as 30 normal control participants were analyzed for the enzyme activities of CAT, SOD, and GSH-Px in the erythrocytes and the total antioxidant capacity and the malondialdehyde concentration in the plasma.

RESULTS

We could show an association of stimulant dependence with a depletion of total antioxidant capacity to 54.6 ± 4.7%, which correlates with a reduced activity of the SOD to 71.3 ± 0.03% compared with healthy control participants (100%).

CONCLUSION

Stimulant-dependent patients had significantly lower antioxidant capacity relative to controls, suggesting that they may be at greater risk for oxidative damage to the brain and other organs.

Stress modulates illness-course of substance use disorders: a translational review

Childhood trauma and post-childhood chronic/repeated stress could increase the risk of a substance use disorder by affecting five stages of addiction illness-course: (a) initial experimentation with substances; (b) shifting from experimental to regular use; (c) escalation from regular use to abuse or dependence; (d) motivation to quit; and (e) risk of (re-)lapse. We reviewed the human literature on relationships between stress and addiction illness-course. We explored per illness-course stage: (i) whether childhood trauma and post-childhood chronic/repeated stress have comparable effects and (ii) whether effects cut across classes of substances of abuse. We further discuss potential underlying mechanisms by which stressors may affect illness-course stages for which we relied on evidence from studies in animals and humans. Stress and substances of abuse both activate stress and dopaminergic motivation systems, and childhood trauma and post-childhood stressful events are more chronic and occur more frequently in people who use substances. Stressors increase risk to initiate early use potentially by affecting trait-like factors of risk-taking, decision making, and behavioral control. Stressors also accelerate transition to regular use potentially due to prior effects of stress on sensitization of dopaminergic motivation systems, cross-sensitizing with substances of abuse, especially in people with high trait impulsivity who are more prone to sensitization. Finally, stressors increase risk for abuse and dependence, attenuate motivation to quit, and increase relapse risk potentially by intensified sensitization of motivational systems, by a shift from positive to negative reinforcement due to sensitization of the amygdala by corticotropin releasing factor, and by increased sensitization of noradrenergic systems. Stress generally affects addiction illness-course across stressor types and across classes of substances of abuse.

Acute effects of 3,4-methylenedioxymethamphetamine and methylphenidate on circulating steroid levels in healthy subjects

3,4-Methylenedioxymethamphetamine (MDMA, 'ecstasy') and methylphenidate are widely used psychoactive substances. MDMA primarily enhances serotonergic neurotransmission, and methylphenidate increases dopamine but has no serotonergic effects. Both drugs also increase norepinephrine, resulting in sympathomimetic properties. Here we studied the effects of MDMA and methylphenidate on 24-hour plasma steroid profiles. 16 healthy subjects (8 men, 8 women) were treated with single doses of MDMA (125 mg), methylphenidate (60 mg), MDMA + methylphenidate, and placebo on 4 separate days using a cross-over study design. Cortisol, cortisone, corticosterone, 11-dehydrocorticosterone, aldosterone, 11-deoxycorticosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androstenedione, and testosterone were repeatedly measured up to 24 h using liquid chromatography-tandem mass spectroscopy. MDMA significantly increased the plasma concentrations of cortisol, corticosterone, 11-dehydrocorticosterone, and 11-deoxycorticosterone and also tended to moderately increase aldosterone levels compared with placebo. MDMA also increased the sum of cortisol + cortisone and the cortisol/cortisone ratio, consistent with an increase in glucocorticoid production. MDMA did not alter the levels of cortisone, DHEA, DHEAS, androstenedione, or testosterone. Methylphenidate did not affect any of the steroid concentrations, and it did not change the effects of MDMA on circulating steroids. In summary, the serotonin releaser MDMA has acute effects on circulating steroids. These effects are not observed after stimulation of the dopamine and norepinephrine systems with methylphenidate. The present findings support the view that serotonin rather than dopamine and norepinephrine mediates the acute pharmacologically induced stimulation of the hypothalamic-pituitary-adrenal axis in the absence of other stressors.

Biological and psychological markers of stress in humans: focus on the Trier Social Stress Test

Validated biological and psychological markers of acute stress in humans are an important tool in translational research. The Trier Social Stress Test (TSST), involving public interview and mental arithmetic performance, is among the most popular methods of inducing acute stress in experimental settings, and reliably increases hypothalamic-pituitary-adrenal axis activation. However, although much research has focused on HPA axis activity, the TSST also affects the sympathetic-adrenal-medullary system, the immune system, cardiovascular outputs, gastric function and cognition. We critically assess the utility of different biological and psychological markers, with guidance for future research, and discuss factors which can moderate TSST effects. We outline the effects of the TSST in stress-related disorders, and if these responses can be abrogated by pharmacological and psychological treatments. Modified TSST protocols are discussed, and the TSST is compared to alternative methods of inducing acute stress. Our analysis suggests that multiple readouts are necessary to derive maximum information; this strategy will enhance our understanding of the psychobiology of stress and provide the means to assess novel therapeutic agents.

Addiction and the adrenal cortex

Substantial evidence shows that the hypophyseal–pituitary–adrenal (HPA) axis and corticosteroids are involved in the process of addiction to a variety of agents, and the adrenal cortex has a key role. In general, plasma concentrations of cortisol (or corticosterone in rats or mice) increase on drug withdrawal in a manner that suggests correlation with the behavioural and symptomatic sequelae both in man and in experimental animals. Corticosteroid levels fall back to normal values in resumption of drug intake. The possible interactions between brain corticotrophin releasing hormone (CRH) and proopiomelanocortin (POMC) products and the systemic HPA, and additionally with the local CRH–POMC system in the adrenal gland itself, are complex. Nevertheless, the evidence increasingly suggests that all may be interlinked and that CRH in the brain and brain POMC products interact with the blood-borne HPA directly or indirectly. Corticosteroids themselves are known to affect mood profoundly and may themselves be addictive. Additionally, there is a heightened susceptibility for addicted subjects to relapse in conditions that are associated with change in HPA activity, such as in stress, or at different times of the day. Recent studies give compelling evidence that a significant part of the array of addictive symptoms is directly attributable to the secretory activity of the adrenal cortex and the actions of corticosteroids. Additionally, sex differences in addiction may also be attributable to adrenocortical function: in humans, males may be protected through higher secretion of DHEA (and DHEAS), and in rats, females may be more susceptible because of higher corticosterone secretion.

Behavioral effects of bidirectional modulators of brain monoamines reserpine and d-amphetamine in zebrafish

Brain monoamines play a key role in the regulation of behavior. Reserpine depletes monoamines, and causes depression and hypoactivity in humans and rodents. In contrast, d-amphetamine increases brain monoamines' levels, and evokes hyperactivity and anxiety. However, the effects of these agents on behavior and in relation to monoamine levels remain poorly understood, necessitating further experimental studies to understand their psychotropic action. Zebrafish (Danio rerio) are rapidly emerging as a promising model organism for drug screening and translational neuroscience research. Here, we have examined the acute and long-term effects of reserpine and d-amphetamine on zebrafish behavior in the novel tank test. Overall, d-amphetamine (5 and 10mg/L) evokes anxiogenic-like effects in zebrafish acutely, but not 7 days later. In contrast, reserpine (20 and 40 mg/L) did not evoke overt acute behavioral effects, but markedly reduced activity 7 days later, resembling motor retardation observed in depression and/or Parkinson's disease. Three-dimensional 'temporal' (X, Y, time) reconstructions of zebrafish locomotion further supports these findings, confirming the utility of 3D-based video-tracking analyses in zebrafish models of drug action. Our results show that zebrafish are highly sensitive to drugs bi-directionally modulating brain monoamines, generally paralleling rodent and clinical findings. Collectively, this emphasizes the potential of zebrafish tests to model complex brain disorders associated with monoamine dysregulation.

The drug effects questionnaire: psychometric support across three drug types

RATIONALE

The Drug Effects Questionnaire (DEQ) is widely used in studies of acute subjective response (SR) to a variety of substances, but the format of the DEQ varies widely across studies, and details of its psychometric properties are lacking. Thus, the field would benefit from demonstrating the reliability and validity of the DEQ for use across multiple substances.

OBJECTIVE

The current study evaluated the psychometric properties of several variations of DEQ items, which assessed the extent to which participants (1) feel any substance effect(s), (2) feel high, (3) like the effects, (4) dislike the effects, and (5) want more of the substance using 100-mm visual analog scales.

METHODS

DEQ data from three placebo-controlled studies were analyzed to examine SR to amphetamine, nicotine, and alcohol. We evaluated the internal structure of the DEQ for use with each substance as well as relationships between scale items, measures of similar constructs, and substance-related behaviors.

RESULTS

Results provided preliminary psychometric support for items assessing each DEQ construct (feel, high, dislike, like, and more).

CONCLUSIONS

Based on the study results, we identify several common limitations of extant variants of the DEQ and recommend an improved version of the measure. The simplicity and brevity of the DEQ combined with its promising psychometric properties support its use in future SR research across a variety of substances.

Relationship of self-reported and acute stress to smoking in emerging adult smokers

OBJECTIVE

In the current study, we examined subjective and objective measures of stress and their relationship to baseline and future cigarette smoking behaviors over a 1-year follow-up in young adult experimental smokers.

METHOD

Participants (N = 56) completed two laboratory sessions to determine subjective and objective responses to a controlled laboratory stressor versus a control task. Baseline measures included drug use and smoking histories and a self-report measure of habitual stress (i.e., daily hassles). They were re-contacted 1 year after the laboratory sessions to determine smoking status.

RESULTS

There was wide variability in smoking trajectories, with 34% of participants increasing their smoking over the course of the year. Contrary to predictions, neither daily hassles nor stress reactivity was related to smoking at baseline or change over the year.

CONCLUSIONS

These preliminary findings suggest that daily stress or responses to acute social stress are not strong predictors of progression in emerging adult smokers.

A randomized, double-blind, placebo-controlled study of an oral, extended-release formulation of phentermine/topiramate for the treatment of obstructive sleep apnea in obese adults

STUDY OBJECTIVES

To evaluate safety and efficacy of phentermine 15 mg plus extended-release topiramate 92 mg for treatment of moderate to severe obstructive sleep apnea (OSA) in obese adults.

DESIGN

This phase 2, randomized, double-blind, placebo-controlled study included 2-week screening and 28-week treatment periods. Overnight polysomnography was performed at baseline, Week 8, and Week 28.

SETTING

Single-center study conducted from August 2008 to September 2009.

PARTICIPANTS

Forty-five subjects with moderate to severe OSA not receiving positive airway pressure (PAP) treatment with body mass index of 30-40 kg/m(2).

INTERVENTIONS

Subjects were randomized to receive placebo (n = 23) or phentermine 15 mg plus extended-release topiramate 92 mg (n = 22). Both groups received lifestyle-modification counseling.

MEASUREMENTS AND RESULTS

Primary endpoint, change in apnea-hypopnea index (AHI), significantly favored phentermine 15 mg plus extended-release topiramate 92 mg (-31.5 events/h, 95% CI: -40.0, -22.9) over placebo (-16.6 events/h, 95% CI: -25.0, -8.2) at Week 28 (P =0.0084). At Week 28, there was a 10.2% (95% CI: -12.7, -7.6; 10.8 kg, 95% CI: -13.5, -8.0) mean decrease in weight in the phentermine 15 mg plus extended-release topiramate 92 mg group compared with 4.3% (95% CI: -6.6, -2.0; 4.7 kg, 95% CI: -7.2, -2.2) in the placebo group (P = 0.0006) and a positive, significant (P = 0.0003) correlation between percent change in weight and change in AHI. Significant improvements in overnight oxygen saturation and reduction in blood pressure compared with placebo were observed. Phentermine 15 mg plus extended-release topiramate 92 mg was well tolerated with low adverse event rates.

CONCLUSIONS

Phentermine 15 mg plus extended-release topiramate 92 mg induced significant weight reductions and concomitant improvements in OSA and related symptoms vs placebo. This suggests weight loss mediated by phentermine 15 mg plus extended-release topiramate 92 mg may be useful in treatment of moderate to severe OSA in obese subjects unable or unwilling to comply with PAP treatment.

Effects of maternal separation and methamphetamine exposure on protein expression in the nucleus accumbens shell and core

Early life adversity has been suggested to predispose an individual to later drug abuse. The core and shell sub-regions of the nucleus accumbens are differentially affected by both stressors and methamphetamine. This study aimed to characterize and quantify methamphetamine-induced protein expression in the shell and core of the nucleus accumbens in animals exposed to maternal separation during early development. Isobaric tagging (iTRAQ) which enables simultaneous identification and quantification of peptides with tandem mass spectrometry (MS/MS) was used. We found that maternal separation altered more proteins involved in structure and redox regulation in the shell than in the core of the nucleus accumbens, and that maternal separation and methamphetamine had differential effects on signaling proteins in the shell and core. Compared to maternal separation or methamphetamine alone, the maternal separation/methamphetamine combination altered more proteins involved in energy metabolism, redox regulatory processes and neurotrophic proteins. Methamphetamine treatment of rats subjected to maternal separation caused a reduction of cytoskeletal proteins in the shell and altered cytoskeletal, signaling, energy metabolism and redox proteins in the core. Comparison of maternal separation/methamphetamine to methamphetamine alone resulted in decreased cytoskeletal proteins in both the shell and core and increased neurotrophic proteins in the core. This study confirms that both early life stress and methamphetamine differentially affect the shell and core of the nucleus accumbens and demonstrates that the combination of early life adversity and later methamphetamine use results in more proteins being affected in the nucleus accumbens than either treatment alone.

TGI Monday?: drug-dependent outpatients report lower stress and more happiness at work than elsewhere

In the general population, experience-sampling studies show that work is the aspect of daily life most associated with momentary unhappiness and a desire to be elsewhere. We assessed whether this holds true for urban outpatients in treatment for heroin and cocaine dependence. In a 25-week natural-history study, 79 employed methadone-maintained misusers of heroin and cocaine carried electronic diaries on which mood and behavior were assessed up to five times per day. Being at work was associated with lower stress, greater happiness, and lower drug craving. Work accounted for 14% of the variance in stress, 30% of the variance in happiness, and 50% of the variance in cocaine craving. Participants with skilled jobs reported more positive and less negative mood states (and lower cocaine craving) at all times compared to participants with semi/unskilled jobs, although the latter reported greater mood improvement at work. In all participants, mood improvements occurred specifically in the presence of coworkers (not other companions). Our seemingly unusual findings might be specific to substance-disorder patients (for whom work may be a respite from drug-using companions), but might also hold for other urban dwellers of similar socioeconomic backgrounds (for whom work may be a respite from environmental stressors).

Stress and the HPA axis: role of glucocorticoids in alcohol dependence

Stress has long been suggested to be an important correlate of uncontrolled drinking and relapse. An important hormonal response system to stress-the hypothalamic-pituitary-adrenal (HPA) axis-may be involved in this process, particularly stress hormones known as glucocorticoids and primarily cortisol. The actions of this hormone system normally are tightly regulated to ensure that the body can respond quickly to stressful events and return to a normal state just as rapidly. The main determinants of HPA axis activity are genetic background, early-life environment, and current life stress. Alterations in HPA axis regulation are associated with problematic alcohol use and dependence; however, the nature of this dysregulation appears to vary with respect to stage of alcohol dependence. Much of this research has focused specifically on the role of cortisol in the risk for, development of, and relapse to chronic alcohol use. These studies found that cortisol can interact with the brain's reward system, which may contribute to alcohol's reinforcing effects. Cortisol also can influence a person's cognitive processes, promoting habit-based learning, which may contribute to habit formation and risk of relapse. Finally, cortisol levels during abstinence may be useful clinical indicators of relapse vulnerability in alcohol-dependent people.

Stress in the daily lives of cocaine and heroin users: relationship to mood, craving, relapse triggers, and cocaine use

RATIONALE

Quantitative real-time data on the stress experienced by drug misusers in their daily lives may provide additional insight into stress's role in drug use.

OBJECTIVE

The purpose of this study is to evaluate stress in relation to craving, mood, relapse-trigger exposure, and cocaine use in cocaine-dependent outpatients.

METHODS

Methadone-maintained cocaine- and heroin-abusing outpatients (N = 114) provided ecological momentary assessment data on handheld computers. Ratings of stress were compared to those of craving and mood and past-hour exposure to putative drug-use triggers in randomly prompted entries and in the 5 h prior to participant-initiated cocaine use reports.

RESULTS

Stress had significant positive relationships with current ratings of craving for cocaine, heroin, and tobacco and with ratings of tiredness, boredom, and irritation, and had significant negative relationships with ratings of happiness and relaxation. Stress was significantly greater in entries in which participants also reported past-hour exposure to negative-mood triggers, most of the drug-exposure triggers, or any trigger involving thoughts about drugs (e.g., tempted out of the blue). The linear increase in stress during the 5-h preceding individual episodes of cocaine use was not significant (p = 0.12), though there was a trend for such an increase before the use episodes that participants attributed to stressful states when they occurred (p = 0.87).

CONCLUSIONS

The findings suggest a complex role of stress in addiction. Stress reported in real time in the natural environment showed strong cross-sectional momentary relationships with craving, mood, and exposure to drug-use trigger. However, the prospective association between stress ratings and cocaine-use episodes was, at best, weak.