Showing papers in "Psychopharmacology in 2017"

Alterations of consciousness and mystical-type experiences after acute LSD in humans

Abstract: Rationale Lysergic acid diethylamide (LSD) is used recreationally and in clinical research. Acute mystical-type experiences that are acutely induced by hallucinogens are thought to contribute to their potential therapeutic effects. However, no data have been reported on LSD-induced mystical experiences and their relationship to alterations of consciousness. Additionally, LSD dose- and concentration-response functions with regard to alterations of consciousness are lacking.

Dreamlike effects of LSD on waking imagery in humans depend on serotonin 2A receptor activation

Abstract: Accumulating evidence indicates that the mixed serotonin and dopamine receptor agonist lysergic acid diethylamide (LSD) induces an altered state of consciousness that resembles dreaming. This study aimed to test the hypotheses that LSD produces dreamlike waking imagery and that this imagery depends on 5-HT2A receptor activation and is related to subjective drug effects. Twenty-five healthy subjects performed an audiorecorded guided mental imagery task 7 h after drug administration during three drug conditions: placebo, LSD (100 mcg orally) and LSD together with the 5-HT2A receptor antagonist ketanserin (40 mg orally). Cognitive bizarreness of guided mental imagery reports was quantified as a standardised formal measure of dream mentation. State of consciousness was evaluated using the Altered State of Consciousness (5D-ASC) questionnaire. LSD, compared with placebo, significantly increased cognitive bizarreness (p < 0.001). The LSD-induced increase in cognitive bizarreness was positively correlated with the LSD-induced loss of self-boundaries and cognitive control (p < 0.05). Both LSD-induced increases in cognitive bizarreness and changes in state of consciousness were fully blocked by ketanserin. LSD produced mental imagery similar to dreaming, primarily via activation of the 5-HT2A receptor and in relation to loss of self-boundaries and cognitive control. Future psychopharmacological studies should assess the differential contribution of the D2/D1 and 5-HT1A receptors to cognitive bizarreness.

Toll-like receptor signaling and stages of addiction

Abstract: Athina Markou and her colleagues discovered persistent changes in adult behavior following adolescent exposure to ethanol or nicotine consistent with increased risk for developing addiction. Building on Dr. Markou’s important work and that of others in the field, researchers at the Bowles Center for Alcohol Studies have found that persistent changes in behavior following adolescent stress or alcohol exposure may be linked to induction of immune signaling in brain. This study aims to illuminate the critical interrelationship of the innate immune system (e.g., toll-like receptors [TLRs], high-mobility group box 1 [HMGB1]) in the neurobiology of addiction. This study reviews the relevant research regarding the relationship between the innate immune system and addiction. Emerging evidence indicates that TLRs in brain, particularly those on microglia, respond to endogenous innate immune agonists such as HMGB1 and microRNAs (miRNAs). Multiple TLRs, HMGB1, and miRNAs are induced in the brain by stress, alcohol, and other drugs of abuse and are increased in the postmortem human alcoholic brain. Enhanced TLR-innate immune signaling in brain leads to epigenetic modifications, alterations in synaptic plasticity, and loss of neuronal cell populations, which contribute to cognitive and emotive dysfunctions. Addiction involves progressive stages of drug binges and intoxication, withdrawal-negative affect, and ultimately compulsive drug use and abuse. Toll-like receptor signaling within cortical-limbic circuits is modified by alcohol and stress in a manner consistent with promoting progression through the stages of addiction.

Don't stress about CRF: assessing the translational failures of CRF 1 antagonists.

Abstract: Dr. Athina Markou sought treatments for a common neural substrate shared by depression and drug dependence. Antagonists of corticotropin-releasing factor (CRF) receptors, a target of interest to her, have not reached the clinic despite strong preclinical rationale and sustained translational efforts. We explore potential causes for the failure of CRF1 antagonists and review recent findings concerning CRF-CRF1 systems in psychopathology. Potential causes for negative outcomes include (1) poor safety and efficacy of initial drug candidates due to bad pharmacokinetic and physicochemical properties, (2) specificity problems with preclinical screens, (3) the acute nature of screens vs. late-presenting patients, (4) positive preclinical results limited to certain models and conditions with dynamic CRF-CRF1 activation not homologous to tested patients, (5) repeated CRF1 activation-induced plasticity that reduces the importance of ongoing CRF1 agonist stimulation, and (6) therapeutic silencing which may need to address CRF2 receptor or CRF-binding protein molecules, constitutive CRF1 activity, or molecules that influence agonist-independent activity or to target structural regions other than the allosteric site bound by all drug candidates. We describe potential markers of activation towards individualized treatment, human genetic, and functional data that still implicate CRF1 systems in emotional disturbance, sex differences, and suggestive clinical findings for CRF1 antagonists in food craving and CRF-driven HPA-axis overactivation. The therapeutic scope of selective CRF1 antagonists now appears narrower than had been hoped. Yet, much remains to be learned about CRF’s role in the neurobiology of dysphoria and addiction and the potential for novel anti-CRF therapies therein.

Nicotine delivery to users from cigarettes and from different types of e-cigarettes

Abstract: Background Delivering nicotine in the way smokers seek is likely to be the key factor in e-cigarette (EC) success in replacing cigarettes. We examined to what degree different types of EC mimic nicotine intake from cigarettes.

The effects of synthetic cannabinoids on executive function.

Abstract: There is a growing use of novel psychoactive substances (NPSs) including synthetic cannabinoids. Synthetic cannabinoid products have effects similar to those of natural cannabis but the new synthetic cannabinoids are more potent and dangerous and their use has resulted in various adverse effects. The purpose of the study was to assess whether persistent use of synthetic cannabinoids is associating with impairments of executive function in chronic users. A total of 38 synthetic cannabinoids users, 43 recreational cannabis users, and 41 non-user subjects were studied in two centers in Hungary and Israel. Computerized cognitive function tests, the classical Stroop word-color task, n-back task, and a free-recall memory task were used. Synthetic cannabinoid users performed significantly worse than both recreational and non-cannabis users on the n-back task (less accuracy), the Stroop task (overall slow responses and less accuracy), and the long-term memory task (less word recall). Additionally, they have also shown higher ratings of depression and anxiety compared with both recreational and non-users groups. This study showed impairment of executive function in synthetic cannabinoid users compared with recreational users of cannabis and non-users. This may have major implications for our understanding of the long-term consequences of synthetic cannabinoid based drugs.

Modelling depression in animals: at the interface of reward and stress pathways.

Abstract: Despite substantial research efforts the aetiology of major depressive disorder (MDD) remains poorly understood, which is due in part to the heterogeneity of the disorder and the complexity of designing appropriate animal models. However, in the last few decades, a focus on the development of novel stress-based paradigms and a focus on using hedonic/anhedonic behaviour have led to renewed optimism in the use of animal models to assess aspects of MDD. Therefore, in this review article, dedicated to Athina Markou, we summarise the use of stress-based animal models for studying MDD in rodents and how reward-related readouts can be used to validate/assess the model and/or treatment. We reveal the use and limitations of chronic stress paradigms, which we split into non-social (i.e. chronic mild stress), social (i.e. chronic social defeat) and drug-withdrawal paradigms for studying MDD and detail numerous reward-related readouts that are employed in preclinical research. Finally, we finish with a section regarding important factors to consider when using animal models. One of the most consistent findings following chronic stress exposure in rodents is a disruption of the brain reward system, which can be easily assessed using sucrose, social interaction, food, drug of abuse or intracranial self-stimulation as a readout. Probing the underlying causes of such alterations is providing a greater understanding of the potential systems and processes that are disrupted in MDD.

Mechanism of depression as a risk factor in the development of Alzheimer's disease: the function of AQP4 and the glymphatic system.

Abstract: Many studies have indicated that a history of depression increases the risk of developing Alzheimer’s disease (AD); however, the potential pathogenestic mechanism by which depression functions as a high risk factor for AD remains unknown. Recently, a “cerebral lymphatic system” referred to as “glymphatic system” has been demonstrated to be responsible for neuronal extracellular waste protein clearance via a paravascular pathway. However, the function of glymphatic pathway has not been determined in depressive disorders. The present study used an animal model of chronic unpredictable mild stress (CUMS) to determine the function of glymphatic pathway by using fluorescence tracers. Immunohistochemistry was used to assess the accumulation of endogenous mouse and exogenous human amyloid beta 42 (Aβ42) in CUMS-treated mice with or without treatment with antidepressant fluoxetine. Glymphatic pathway circulation was impaired in mice treated with CUMS; moreover, glymphatic pathway dysfunction suppressed Aβ42 metabolism, because the accumulation of endogenous and exogenous Aβ42 was increased in the brains of the CUMS-treated mice. However, treatment with fluoxetine reversed these destructive effects of CUMS on glymphatic system. In anhedonic mice, the expression of the water channel aquaporin 4 (AQP4), a factor in glymphatic pathway dysfunction, was down-regulated in cortex and hippocampus. The dysfunction of glymphatic system suggested why a history of depression may be a strong risk factor for AD in anhedonic mice. We hope our study will contribute to an understanding of the risk mechanism of depressive disorder in the development of AD and the mechanisms of antidepressant therapies in AD.

Cocaine administration dose-dependently increases sexual desire and decreases condom use likelihood: The role of delay and probability discounting in connecting cocaine with HIV.

Abstract: Objectives Although cocaine use has been linked to sexual HIV risk behavior for decades, the direct effects of cocaine on sexual desire and sexual decision-making are unexamined. Research suggests delay discounting (devaluation of future outcomes) and probability discounting (devaluation of uncertain outcomes) play roles in condom use decisions. This study examined the effect of cocaine administration on sexual desire, hypothetical condom use, and discounting tasks.

Oxycodone self-administration in male and female rats

Abstract: Oxycodone is one of the most widely prescribed painkillers in the USA. However, its use is complicated by high abuse potential. As sex differences have been described in drug addiction, the present study tested for sex differences in intravenous oxycodone self-administration in rats. Male and female Sprague-Dawley rats were implanted with jugular vein catheters and trained to self-administer oxycodone (0.03 mg/kg/infusion) under fixed ratio 1 (FR1), FR2, and FR5 schedules of reinforcement followed by a dose-response study to assess sensitivity to the reinforcing effects of oxycodone. In separate rats, sucrose pellet self-administration was assessed under an FR1 schedule to determine whether sex differences in oxycodone self-administration could be generalized across reinforcers. In separate rats, oxycodone distribution to plasma and brain was measured after intravenous drug delivery. In the first 3 trials under an FR1 schedule of reinforcement, male rats self-administered more oxycodone than females. In contrast, females self-administered more sucrose pellets. Under FR2 and FR5 schedules, no significant sex differences in oxycodone intake were observed, although female rats had significantly more inactive lever presses. Male and female rats showed similar inverted U-shaped dose-effect functions, with females tending to self-administer more oxycodone than males at higher doses. No significant sex differences were observed in plasma or brain oxycodone levels, suggesting that sex differences in oxycodone self-administration behavior were not due to pharmacokinetics. Our results suggest subtle sex differences in oxycodone self-administration, which may influence the abuse liability of oxycodone and have ramifications for prescription opioid addiction treatment.

Latent factor structure of a behavioral economic marijuana demand curve.

Abstract: Rationale Drug demand, or relative value, can be assessed via analysis of behavioral economic purchase task performance Five demand indices are typically obtained from drug purchase tasks

A short history of the 5-HT2C receptor: from the choroid plexus to depression, obesity and addiction treatment.

Abstract: This paper is a personal account on the discovery and characterization of the 5-HT2C receptor (first known as the 5-HT1C receptor) over 30 years ago and how it translated into a number of unsuspected features for a G protein-coupled receptor (GPCR) and a diversity of clinical applications. The 5-HT2C receptor is one of the most intriguing members of the GPCR superfamily. Initially referred to as 5-HT1CR, the 5-HT2CR was discovered while studying the pharmacological features and the distribution of [3H]mesulergine-labelled sites, primarily in the brain using radioligand binding and slice autoradiography. Mesulergine (SDZ CU-085), was, at the time, best defined as a ligand with serotonergic and dopaminergic properties. Autoradiographic studies showed remarkably strong [3H]mesulergine-labelling to the rat choroid plexus. [3H]mesulergine-labelled sites had pharmacological properties different from, at the time, known or purported 5-HT receptors. In spite of similarities with 5-HT2 binding, the new binding site was called 5-HT1C because of its very high affinity for 5-HT itself. Within the following 10 years, the 5-HT1CR (later named 5-HT2C) was extensively characterised pharmacologically, anatomically and functionally: it was one of the first 5-HT receptors to be sequenced and cloned. The 5-HT2CR is a GPCR, with a very complex gene structure. It constitutes a rarity in the GPCR family: many 5-HT2CR variants exist, especially in humans, due to RNA editing, in addition to a few 5-HT2CR splice variants. Intense research led to therapeutically active 5-HT2C receptor ligands, both antagonists (or inverse agonists) and agonists: keeping in mind that a number of antidepressants and antipsychotics are 5-HT2CR antagonists/inverse agonists. Agomelatine, a 5-HT2CR antagonist is registered for the treatment of major depression. The agonist Lorcaserin is registered for the treatment of aspects of obesity and has further potential in addiction, especially nicotine/ smoking. There is good evidence that the 5-HT2CR is involved in spinal cord injury-induced spasms of the lower limbs, which can be treated with 5-HT2CR antagonists/inverse agonists such as cyproheptadine or SB206553. The 5-HT2CR may play a role in schizophrenia and epilepsy. Vabicaserin, a 5-HT2CR agonist has been in development for the treatment of schizophrenia and obesity, but was stopped. As is common, there is potential for further indications for 5-HT2CR ligands, as suggested by a number of preclinical and/or genome-wide association studies (GWAS) on depression, suicide, sexual dysfunction, addictions and obesity. The 5-HT2CR is clearly affected by a number of established antidepressants/antipsychotics and may be one of the culprits in antipsychotic-induced weight gain.

Antipsychotic-induced hyperprolactinemia: synthesis of world-wide guidelines and integrated recommendations for assessment, management and future research

Abstract: Hyperprolactinemia is a highly prevalent adverse effect of many antipsychotic agents, with potentially serious health consequences. Several guidelines have been developed for the management of this condition; yet, their concordance has not been evaluated. The objectives of this paper were (1) to review current clinical guidelines; (2) to review key systematic evidence for management; and (3) based on our findings, to develop an integrated management recommendation specific to male and female patients who are otherwise clinically stabilised on antipsychotics. We performed searches of Medline and EMBASE, supplemented with guideline-specific database and general web searches, to identify clinical guidelines containing specific recommendations for antipsychotic-induced hyperprolactinemia, produced/updated 01/01/2010–15/09/2016. A separate systematic search was performed to identify emerging management approaches described in reviews and meta-analyses published ≥ 2010. There is some consensus among guidelines relating to baseline PRL screening (8/12 guidelines), screening for differential diagnosis (7/12) and discontinuing/switching PRL-raising agent (7/12). Guidelines otherwise diverge substantially regarding most aspects of screening, monitoring and management (e.g. treatment with dopamine agonists). There is an omission of clear sex-specific recommendations. Systematic literature on management approaches is promising; more research is needed. An integrated management recommendation is presented to guide sex-specific clinical response to antipsychotic-induced hyperprolactinemia. Key aspects include asymptomatic hyperprolactinemia monitoring and fertility considerations with PRL normalisation. Further empirical work is key to shaping robust guidelines for antipsychotic-induced hyperprolactinemia. The integrated management recommendation can assist clinician and patient decision-making, with the goal of balancing effective psychiatric treatment while minimising PRL-related adverse health effects in male and female patients.

Effects of varenicline versus transdermal nicotine replacement therapy on cigarette demand on quit day in individuals with substance use disorders

Abstract: Cigarette demand is a behavioral economic measure of the relative value of cigarettes. Decreasing the value of cigarette reinforcement may help with quitting smoking. This study aimed to evaluate the effects of initial use of varenicline (VAR) versus nicotine replacement therapy (NRT) on demand for cigarettes on quit day among smokers with substance use disorders (SUD) and to determine whether reduced demand was associated with subsequent abstinence from smoking at 1 and 3 months. Participants (N = 110) were randomized to double-blind, double-placebo conditions: VAR with placebo NRT or NRT with placebo capsules. The cigarette purchase task (CPT) was used to assess demand for cigarettes at baseline and on quit day, following a 1-week medication dose run-up/placebo capsule lead-in and first day use of the patch. Demand for cigarettes decreased from baseline to quit day without significant differences between medications. Reductions in CPT intensity (number of cigarettes that would be smoked if they were free) and CPT breakpoint (lowest price at which no cigarettes would be purchased) predicted greater likelihood of abstaining on quit day. Reduced intensity predicted length of abstinence at 1 and 3 months while reduced breakpoint predicted only 1 month length of abstinence. Initial therapeutic doses of VAR and NRT resulted in similar reductions in cigarette reinforcement. Larger initial reductions in demand on quit day were associated with early success with abstaining from cigarettes. Behavioral economic approaches may be useful for identifying individuals who benefit less from pharmacotherapy and may need additional treatment resources. https://clinicaltrials.gov/ct2/show/NCT00756275

Saikosaponin D relieves unpredictable chronic mild stress induced depressive-like behavior in rats: involvement of HPA axis and hippocampal neurogenesis.

Abstract: Saikosaponin D (SSD), a major bioactive component isolated from Radix Bupleuri, has been reported to exert neuroprotective properties. The present study was designed to investigate the anti-depressant-like effects and the potential mechanisms of SSD. Behavioural tests including sucrose preference test (SPT), open field test (OFT) and forced swim test (FST) were performed to study the antidepressant-like effects of SSD. In addition, we examined corticosterone and glucocorticoid receptor (GR) levels to evaluate hypothalamic-pituitary-adrenal (HPA) axis function. Furthermore, hippocampal neurogenesis was assessed by testing doublecortin (DCX) levels, and neurotrophic molecule levels were also investigated in the hippocampus of rats. We found that unpredictable chronic mild stress (UCMS) rats displayed lost body weight, decreased sucrose consumption in SPT, reduced locomotive activity in OFT, and increased immobility time in FST. Chronic treatment with SSD (0.75, 1.50 mg/kg) remarkably ameliorated the behavioral deficiency induced by UCMS procedure. SSD administration downregulated elevated serum corticosterone levels, as well as alleviated the suppression of GR expression and nuclear translocation caused by UCMS, suggesting that SSD is able to remit the dysfunction of HPA axis. In addition, Western blot and immunohistochemistry analysis showed that SSD treatment significantly increased the generation of neurons in the hippocampus of UCMS rats indicated by elevated DCX levels. Moreover, hippocampal neurotrophic molecule levels of UCMS rats such as phosphorylated cAMP response element binding protein (p-CREB) and brain-derived neurotrophic factor (BDNF) were raised after SSD treatment. Together, Our results suggest that SSD opposed UCMS-induced depressive behaviors in rats, which was mediated, partially, by the enhancement of HPA axis function and consolidation of hippocampal neurogenesis.

Deficits in autonomic indices of emotion regulation and reward processing associated with prescription opioid use and misuse

Abstract: Prescription opioid misuse and high-dose opioid use may result in allostatic dysregulation of hedonic brain circuitry, leading to reduced emotion regulation capacity. In particular, opioid misuse may blunt the ability to experience and upregulate positive affect from natural rewards. The purpose of this study was to examine associations between opioid use/misuse and autonomic indices of emotion regulation capability in a sample of chronic pain patients receiving prescription opioid pharmacotherapy. Chronic pain patients taking long-term opioid analgesics (N = 40) completed an emotion regulation task while heart rate variability (HRV) was recorded, and also completed self-report measures of opioid misuse, craving, pain severity, and emotional distress. Based on a validated cut-point on the Current Opioid Misuse Measure, participants were grouped as opioid misusers or non-misusers. Opioid misuse status and morphine equivalent daily dose (MEDD) were examined as predictors of HRV and self-reports of emotion regulation. Opioid misusers exhibited significantly less HRV during positive and negative emotion regulation, and significantly less positive effect, than non-misusers, after controlling for confounders including pain severity and emotional distress. MEDD was inversely associated with positive emotion regulation efficacy. Findings implicate the presence of reward processing deficits among chronic pain patients with opioid-misusing behaviors, and opioid dosage was associated with deficient emotion regulation, suggesting the presence of compromised top-down cognitive control over bottom-up hedonic processes. Emotion regulation among opioid misusers may represent an important treatment target.

The impact of cognitive training in substance use disorder: the effect of working memory training on impulse control in methamphetamine users.

Abstract: Impulsivity is a vulnerability trait for poor self-regulation in substance use disorder (SUD). Working memory (WM) training improves impulsivity and self-regulation in psychiatric disorders. Here we test WM training in methamphetamine use disorder (MUD). There are 15 MUD patients receiving inpatient treatment as usual (TAU) and 20 who additionally completed WM cognitive training (CT) and 25 healthy controls (HC). MANCOVA repeated measures analyses examined changes in impulsivity and self-regulation at baseline and after 4 weeks. Post hoc t tests confirmed that at baseline, feelings of self-control were significantly lower in the MUD (t = 2.001, p = 0.05) and depression was higher (t = 4.980, p = 0.001), as was BIS total impulsivity (t = 5.370, p = 0.001) compared to the HC group. Total self-regulation score was higher in HC than MUD patients (t = 5.370, p = 0.001). CT had a 35% learning rate (R 2 = 0.3523, p < 0.05). Compared to follow-up TAU, follow-up CT group had higher self-reported mood scores (t = 2.784, p = 0.01) and higher compared to CT baseline (t = 2.386, p = 0.036). Feelings of self-control were higher in CT than TAU at follow-up (t = 2.736, p = 0.012) and also compared to CT baseline (t = 3.390, p = 0.006), lack of planning significantly improved in CT between baseline and follow-up (t = 2.219, p = 0.048), as did total impulsivity scores (t = 2.085, p = 0.048). Measures of self-regulation were improved in the CT group compared to TAU at follow-up, in total score (t = 2.442, p = 0.038), receiving score (t = 2.314, p = 0.029) and searching score (t = 2.362, p = 0.027). Implementing self-regulation was higher in the CT group compared to TAU (t = 2.373, p = 0.026). WM training may improve control of impulsivity and self-regulation in people with MUD.

Inhibition of serotonin transporters disrupts the enhancement of fear memory extinction by 3,4-methylenedioxymethamphetamine (MDMA).

Abstract: 3,4-Methylenedioxymethamphetamine (MDMA) persistently improves symptoms of post-traumatic stress disorder (PTSD) when combined with psychotherapy. Studies in rodents suggest that these effects can be attributed to enhancement of fear memory extinction. Therefore, MDMA may improve the effects of exposure-based therapy for PTSD, particularly in treatment-resistant patients. However, given MDMA’s broad pharmacological profile, further investigation is warranted before moving to a complex clinical population. We aimed to inform clinical research by providing a translational model of MDMA’s effect, and elucidating monoaminergic mechanisms through which MDMA enhances fear extinction. We explored the importance of monoamine transporters targeted by MDMA to fear memory extinction, as measured by reductions in conditioned freezing and fear-potentiated startle (FPS) in mice. Mice were treated with selective inhibitors of individual monoamine transporters prior to combined MDMA treatment and fear extinction training. MDMA enhanced the lasting extinction of FPS. Acute and chronic treatment with a 5-HT transporter (5-HTT) inhibitor blocked MDMA’s effect on fear memory extinction. Acute inhibition of dopamine (DA) and norepinephrine (NE) transporters had no effect. 5-HT release alone did not enhance extinction. Blockade of MDMA’s effect by 5-HTT inhibition also downregulated 5-HT2A-mediated behavior, and 5-HT2A antagonism disrupted MDMA’s effect on extinction. We validate enhancement of fear memory extinction by MDMA in a translational behavioral model, and reveal the importance of 5-HTT and 5-HT2A receptors to this effect. These observations support future clinical research of MDMA as an adjunct to exposure therapy, and provide important pharmacological considerations for clinical use in a population frequently treated with 5-HTT inhibitors.

Effect of prior foot shock stress and Δ 9 -tetrahydrocannabinol, cannabidiolic acid, and cannabidiol on anxiety-like responding in the light-dark emergence test in rats

Abstract: Cannabis is commonly used by humans to relieve stress. Here, we evaluate the potential of intraperitoneally (i.p.) administered Δ9-tetrahydrocannabiol (THC) and cannabidiolic acid (CBDA, the precursor of cannabidiol [CBD]) to produce dose-dependent effects on anxiety-like responding in the light-dark (LD) emergence test of anxiety-like responding in rats, when administered acutely or chronically (21 days). As well, we evaluate the potential of THC, CBDA, and CBD to reduce anxiogenic responding produced by foot shock (FS) stress 24 h prior to the LD test. In the absence of the explicit FS stressor, THC (1 and 10 mg/kg) produced anxiogenic-like responding when administered acutely or chronically, but CBDA produced neither anxiogenic- nor anxiolytic-like responding. Administration of FS stress 24 h prior to the LD test enhanced anxiogenic-like responding (reduced time spent and increased latency to enter the light compartment) in rats pretreated with either vehicle (VEH) or THC (1 mg/kg); however, administration of CBDA (0.1–100 μg/kg) or CBD (5 mg/kg) prevented the FS-induced anxiogenic-like responding (an anxiolytic-like effect). The 5-hydroxytryptamine 1A (5-HT1A) receptor antagonist, WAY100635, reversed CBDA’s anxiolytic effect (1 μg/kg). Combining an anxiolytic dose of CBDA (1 μg/kg) or CBD (5 mg/kg) with an anxiogenic dose of THC (1 mg/kg) did not modify THC’s anxiogenic effect. These results suggest the anxiolytic effects of CBDA and CBD may require the presence of a specific stressor.

Ellagic acid ameliorates learning and memory deficits in a rat model of Alzheimer’s disease: an exploration of underlying mechanisms

Abstract: Rationale Alzheimer’s disease (AD) is a neurodegenerative disorder with irreversible loss of intellectual abilities. Current therapies for AD are still insufficient.

Do alcohol-dependent patients show different neural activation during response inhibition than healthy controls in an alcohol-related fMRI go/no-go-task?

Abstract: Alcohol dependence is associated with impaired response inhibition and heightened cue reactivity towards alcohol-related stimuli. Several brain areas, but mainly prefrontal structures, have been linked to response inhibition in addiction. This study aimed at combining both aspects: salience of drug-associated cues and response inhibition using a go/no-go task with alcohol-associated stimuli during functional magnetic resonance imaging (fMRI). Nineteen abstinent alcohol-dependent patients (ADP) and 21 healthy control subjects (HC) were compared on blood oxygen level-dependent (BOLD) responses during successful inhibition of no-go stimuli and successful reactions to go stimuli. ADP and HC did not significantly differ in their behavioural performance in the task. However, both groups performed worse during the inhibition of alcoholic-associated stimuli compared to neutral stimuli. On the neural level, ADP displayed enhanced BOLD activity relative to HC during successful response inhibition in several areas involved in visual processing, cognitive and impulse control, including occipital structures, anterior cingulate gyrus, medial frontal gyrus and medial orbitofrontal cortex. We interpret these findings as a possible compensation strategy for impaired cognitive processing. Furthermore, the results underline the impact of salience of alcohol-related stimuli on response inhibition, which seems to affect both ADP and HC.

Social defeat disrupts reward learning and potentiates striatal nociceptin/orphanin FQ mRNA in rats.

Abstract: Mood disorders can be triggered by stress and are characterized by deficits in reward processing, including disrupted reward learning (the ability to modulate behavior according to past rewards). Reward learning is regulated by the anterior cingulate cortex (ACC) and striatal circuits, both of which are implicated in the pathophysiology of mood disorders. Here, we assessed in rats the effects of a potent stressor (social defeat) on reward learning and gene expression in the ACC, ventral tegmental area (VTA), and striatum. Adult male Wistar rats were trained on an operant probabilistic reward task (PRT) and then exposed to 3 days of social defeat before assessment of reward learning. After testing, the ACC, VTA, and striatum were dissected, and expression of genes previously implicated in stress was assessed. Social defeat blunted reward learning (manifested as reduced response bias toward a more frequently rewarded stimulus) and was associated with increased nociceptin/orphanin FQ (N/OFQ) peptide mRNA levels in the striatum and decreased Fos mRNA levels in the VTA. Moreover, N/OFQ peptide and nociceptin receptor mRNA levels in the ACC, VTA and striatum were inversely related to reward learning. The behavioral findings parallel previous data in humans, suggesting that stress similarly disrupts reward learning in both species. Increased striatal N/OFQ mRNA in stressed rats characterized by impaired reward learning is consistent with accumulating evidence that antagonism of nociceptin receptors, which bind N/OFQ, has antidepressant-like effects. These results raise the possibility that nociceptin systems represent a molecular substrate through which stress produces reward learning deficits in mood disorders.

Blunted stress reactivity in chronic cannabis users.

Abstract: One of the most commonly cited reasons for chronic cannabis use is to cope with stress Consistent with this, cannabis users have shown reduced emotional arousal and dampened stress reactivity in response to negative imagery To our knowledge, the present study represents the first to examine the effects of an acute stress manipulation on subjective stress and salivary cortisol in chronic cannabis users compared to non-users Forty cannabis users and 42 non-users were randomly assigned to complete either the stress or no stress conditions of the Maastricht Acute Stress Test (MAST) The stress condition of the MAST manipulates both physiological (placing hand in ice bath) and psychosocial stress (performing math under conditions of social evaluation) Participants gave baseline subjective stress ratings before, during, and after the stress manipulation Cortisol was measured from saliva samples obtained before and after the stress manipulation Further, cannabis cravings and symptoms of withdrawal were measured Subjective stress ratings and cortisol levels were significantly higher in non-users in the stress condition relative to non-users in the no stress condition In contrast, cannabis users demonstrated blunted stress reactivity; specifically, they showed no increase in cortisol and a significantly smaller increase in subjective stress ratings The stress manipulation had no impact on cannabis users’ self-reported cravings or withdrawal symptoms Chronic cannabis use is associated with blunted stress reactivity Future research is needed to determine whether this helps to confer resiliency or vulnerability to stress-related psychopathology as well as the mechanisms underlying this effect

Context and craving during stressful events in the daily lives of drug-dependent patients

Abstract: Knowing how stress manifests in the lives of people with substance-use disorders could help inform mobile “just in time” treatment. The purpose of this paper is to examine discrete episodes of stress, as distinct from the fluctuations in background stress assessed in most EMA studies. For up to 16 weeks, outpatients on opioid-agonist treatment carried smartphones on which they initiated an entry whenever they experienced a stressful event (SE) and when randomly prompted (RP) three times daily. Participants reported the severity of stress and craving and the context of the report (location, activities, companions). Decomposition of covariance was used to separate within-person from between-person effects; r effect sizes below are within-person. Participants (158 of 182; 87%) made 1787 stress-event entries. Craving for opioids increased with stress severity (r effect = 0.50). Stress events tended to occur in social company (with acquaintances, 0.63, friends, 0.17, or on the phone, 0.41) rather than with family (spouse, −0.14; child, −0.18), and in places with more overall activity (bars, 0.32; outside, 0.28; walking, 0.28) and more likelihood of unexpected experiences (with strangers, 0.17). Being on the internet was slightly protective (−0.22). Our prior finding that being at the workplace protects against background stress in our participants was partly supported in these stressful-event data. The contexts of specific stressful events differ from those we have seen in prior studies of ongoing background stress. However, both are associated with drug craving.

Predicting relapse with individual residual symptoms in major depressive disorder: a reanalysis of the STAR*D data.

Abstract: Residual symptoms are detrimental to prognosis in major depressive disorder (MDD); however, little is known about the contribution of each residual symptom in predicting outcomes. The objective of this analysis was to identify which individual symptoms, based on self-report and clinician interview, could predict subsequent relapse. The data of 1133 outpatients with nonpsychotic MDD who entered a 12-month naturalistic follow-up phase after achieving remission with level 1 treatment (i.e., citalopram for up to 14 weeks) and had at least one post-baseline contact in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) trial were analyzed. Specific residual symptoms in the 16-item Quick Inventory of Depressive Symptomatology, self-report (QIDS-SR16) and clinician rating (QIDS-C16), at the follow-up entry that predicted relapse were identified, using a Cox proportional hazards model. The following three QIDS-SR16 symptoms were significantly associated with subsequent relapse: restlessness (HR = 1.197, p = 0.018), hypersomnia (HR = 1.190, p = 0.009), and weight change (HR = 1.127, p = 0.041). On the other hand, the following three symptoms in the QIDS-C16 at the follow-up entry were significantly associated with relapse in the follow-up phase: restlessness (HR = 1.328, p = 0.001), sleep onset insomnia (HR = 1.129, p = 0.047), and weight change (HR = 1.125, p = 0.045). The original trial was not designed to evaluate the issue addressed herein. Individual symptoms may be associated with each other and functional status was not addressed. Some residual symptoms, including restlessness, insomnia, and weight change, may help better identify patients with MDD vulnerable to relapse. Contribution of individual residual symptoms to subsequent relapse was similar between self-report and clinician-rated symptoms.

Antireward, compulsivity, and addiction: seminal contributions of Dr. Athina Markou to motivational dysregulation in addiction.

Abstract: Addiction is defined as a chronically relapsing disorder characterized by compulsive drug seeking that is hypothesized to derive from multiple sources of motivational dysregulation. Dr. Athina Markou made seminal contributions to our understanding of the neurobiology of addiction with her studies on the dysregulation of reward function using animal models with construct validity. Repeated overstimulation of the reward systems with drugs of abuse decreases reward function, characterized by brain stimulation reward and presumbably reflecting dysphoria-like states. The construct of negative reinforcement, defined as drug taking that alleviates a negative emotional state that is created by drug abstinence, is particularly relevant as a driving force in both the withdrawal/negative affect and preoccupation/anticipation stages of the addiction cycle. The negative emotional state that drives such negative reinforcement is hypothesized to derive from the dysregulation of key neurochemical circuits that drive incentive-salience/reward systems (dopamine, opioid peptides) in the ventral striatum and from the recruitment of brain stress systems (corticotropin-releasing factor, dynorphin) within the extended amygdala. As drug taking becomes compulsive-like, the factors that motivate behavior are hypothesized to shift to drug-seeking behavior that is driven not only by positive reinforcement but also by negative reinforcement. This shift in motivation is hypothesized to reflect the allostatic misregulation of hedonic tone such that drug taking makes the hedonic negative emotional state worse during the process of seeking temporary relief with compulsive drug taking.

Antidepressant effects of combination of brexpiprazole and fluoxetine on depression-like behavior and dendritic changes in mice after inflammation.

Abstract: Rationale Addition of low doses of atypical antipsychotic drugs with selective serotonin reuptake inhibitors (SSRIs) could promote a rapid antidepressant effect in treatment-resistant patients with major depression. Brexpiprazole, a new atypical antipsychotic drug, has been used as adjunctive therapy for the treatment of major depression.

Effects of nalfurafine on the reinforcing, thermal antinociceptive, and respiratory-depressant effects of oxycodone: modeling an abuse-deterrent opioid analgesic in rats.

Abstract: Strategies to reduce the misuse of mu opioid agonists are critically needed. Previous work has shown that kappa opioid agonists can diminish the abuse-related effects and augment the antinociceptive effects of mu agonists. However, use of traditional kappa agonists is limited by their dysphoric side effects. The current study examined the effects of nalfurafine, a clinically available atypical kappa agonist, on the reinforcing, thermal antinociceptive, and respiratory-depressant effects of oxycodone in male rats. To determine oxycodone/nalfurafine mixture proportions to be examined intravenously across procedures, a progressive ratio (PR) self-administration procedure compared the reinforcing effects of oxycodone (56 μg/kg/inj) available alone or as a mixture with co-administered nalfurafine (0.32, 1, or 3.2 μg/kg/inj), corresponding to oxycodone/nalfurafine proportions of 175:1, 56:1, and 18:1, respectively. Next, PR and thermal antinociception dose-effect functions were each determined for oxycodone, nalfurafine, and the same oxycodone/nalfurafine mixture proportions. Finally, the respiratory-depressant effects of equi-antinociceptive doses of oxycodone, nalfurafine, and the mixtures were compared. Nalfurafine decreased the reinforcing effects of oxycodone, and the 18:1 mixture did not function as a reinforcer. Oxycodone and nalfurafine each produced dose-dependent antinociception, and the mixtures produced additive antinociception. In addition, antinociceptive doses of the 56:1 and 18:1 mixtures did not produce respiratory depression. These results suggest that nalfurafine may augment the thermal antinociceptive effects while reducing the reinforcing and respiratory-depressant effects of oxycodone.

Drug cue reactivity involves hierarchical instrumental learning: evidence from a biconditional Pavlovian to instrumental transfer task

Abstract: Rationale Drug cue reactivity plays a crucial role in addiction, yet the underlying mechanisms are poorly understood. According to the binary associative account, drug stimuli retrieve an expectation of the drug outcome, which, in turn, elicits the associated drug-seeking response (S-O-R). By contrast, according to the hierarchical account, drug stimuli retrieve an expectation that the contingency between the drug-seeking response and the drug outcome is currently more effective, promoting performance of the drug-seeking response (S:R-O).

Rapid evidence review of the comparative effectiveness, harms, and cost-effectiveness of pharmacogenomics-guided antidepressant treatment versus usual care for major depressive disorder

Abstract: This study aims to conduct an evidence review of the effectiveness, harms, and cost-effectiveness of pharmacogenomics-guided antidepressant treatment for major depressive disorder. We searched MEDLINE®, the Cochrane Central Registry of Controlled Trials, and PsycINFO through February 2017. We used prespecified criteria to select studies, abstract data, and rate internal validity and strength of the evidence (PROSPERO number CRD42016036358). We included two randomized trials (RCT), five controlled cohort studies, and six modeling studies of mostly women in their mid-40s with few comorbidities. CNSDose (ABCB1, ABCC1, CYP2C19, CYP2D6, UGT1A1) is the only pharmacogenomics test that significantly improved remission (one additional remitting patient in 12 weeks per three genotyped, 95% CI 1.7 to 3.5) and reduced intolerability in an RCT. ABCB1 genotyping leads to one additional remitting patient in 5 weeks per three genotyped (95% CI 3 to 20), but tolerability was not reported. In an RCT, GeneSight (CYP2D6, CYPC19, CYP1A2, SLC6A4, HTR2A) did not statistically significantly improve remission, and evidence is inconclusive about its tolerability. Evidence is generally low strength because RCTs were few and underpowered. Cost-effectiveness is unclear due to lack of directly observed cost-effectiveness outcomes. We found no studies that evaluated whether pharmacogenomics shortens time to optimal treatment, whether improvements were due to switches to genetically congruent medication, or whether effectiveness varies based on test and patient characteristics. Certain pharmacogenomics tools show promise of improving short-term remission rates in women in their mid-40s with few comorbidities. But, important evidence limitations preclude recommending their widespread use and indicate a need for further research.