Childhood maltreatment and amygdala connectivity in methamphetamine dependence: a pilot study

Childhood Maltreatment and Amygdala-Mediated Anxiety and Posttraumatic Stress Following Adult Trauma

Background

Childhood abuse (physical, emotional, and sexual) is associated with aberrant connectivity of the amygdala, a key threat-processing region. Heightened amygdala activity also predicts adult anxiety and posttraumatic stress disorder (PTSD) symptoms, as do experiences of childhood abuse. The current study explored whether amygdala resting-state functional connectivity may explain the relationship between childhood abuse and anxiety and PTSD symptoms following trauma exposure in adults.

Methods

Two weeks posttrauma, adult trauma survivors (n = 152, mean age [SD] = 32.61 [10.35] years; women = 57.2%) completed the Childhood Trauma Questionnaire and underwent resting-state functional magnetic resonance imaging. PTSD and anxiety symptoms were assessed 6 months posttrauma. Seed-to-voxel analyses evaluated the association between childhood abuse and amygdala resting-state functional connectivity. A mediation model evaluated the potential mediating role of amygdala connectivity in the relationship between childhood abuse and posttrauma anxiety and PTSD.

Results

Childhood abuse was associated with increased amygdala connectivity with the precuneus while covarying for age, gender, childhood neglect, and baseline PTSD symptoms. Amygdala-precuneus resting-state functional connectivity was a significant mediator of the effect of childhood abuse on anxiety symptoms 6 months posttrauma (B = 0.065; 95% CI, 0.013-0.130; SE = 0.030), but not PTSD. A secondary mediation analysis investigating depression as an outcome was not significant.

Conclusions

Amygdala-precuneus connectivity may be an underlying neural mechanism by which childhood abuse increases risk for anxiety following adult trauma. Specifically, this heightened connectivity may reflect attentional vigilance for threat or a tendency toward negative self-referential thoughts. Findings suggest that childhood abuse may contribute to longstanding upregulation of attentional vigilance circuits, which makes one vulnerable to anxiety-related symptoms in adulthood.

The Effectiveness of Mindfulness in the Treatment of Methamphetamine Addiction Symptoms: Does Neuroplasticity Play a Role?

INTRODUCTION

Methamphetamine is a highly stimulating psychoactive drug that causes life-threatening addictions and affects millions of people around the world. Its effects on the brain are complex and include disturbances in the neurotransmitter systems and neurotoxicity. There are several known treatment methods, but their effectiveness is moderate. It must be emphasised that no drugs have been approved for treatment. For this reason, there is an urgent need to develop new, effective, and safe treatments for methamphetamine. One of the potential treatments is mindfulness meditation. In recent years, this technique has been researched extensively in the context of many neurological and psychiatric disorders.

METHODS

This review explores the use of mindfulness in the treatment of methamphetamine addiction. Searches were conducted in the PubMed/Medline, Research Gate, and Cochrane databases.

RESULTS

Ten studies were identified that used mindfulness-based interventions in the treatment of methamphetamine addiction. The results show that mindfulness is an effective form of reducing hunger, risk of relapses, stress indicators, depression, and aggression, alone or in combination with transcranial direct current stimulation (tDCS). Mindfulness also improved the cognitive function in addicts. The included studies used only behavioural measures. The potential mechanisms of mindfulness in addiction were explained, and it was proposed that it can induce neuroplasticity, alleviating the symptoms of addiction.

CONCLUSIONS

Evidence from the studies suggest that mindfulness may be an effective treatment option for methamphetamine addiction, used alone or in combination with tDCS. However, further high-quality research is required to establish the role of this treatment option in this field. The use of neuroimaging and neurophysiological measures is fundamental to understand the mechanisms of mindfulness.

The Dichotomy of Threat and Deprivation as Subtypes of Childhood Maltreatment: Differential Functional Connectivity Patterns of Threat and Reward Circuits in an Adult Trauma Sample

BACKGROUND

Childhood maltreatment is associated with reduced activation of the nucleus accumbens, a central region in the reward network, and overactivity in the amygdala, a key region in threat processing. However, the long-lasting impact of these associations in the context of later-life stress is not well understood. The current study explored the association between childhood threat and deprivation and functional connectivity of threat and reward regions in an adult trauma sample.

METHODS

Trauma survivors (N = 169; mean age [SD] = 32.2 [10.3] years; female = 55.6%) were recruited from a level I trauma center. Two weeks after injury, participants completed the Childhood Trauma Questionnaire (measuring experiences of threat and deprivation) and underwent resting-state functional magnetic resonance imaging. Seed-to-voxel analyses evaluated the effect of childhood threat and deprivation on amygdala and nucleus accumbens resting-state connectivity.

RESULTS

Higher levels of threat were associated with increased connectivity between the right nucleus accumbens with temporal fusiform gyrus/parahippocampal gyrus and the left amygdala and the precuneus (false discovery rate-corrected p < .05). After controlling for posttraumatic symptoms 2 weeks posttrauma and lifetime trauma exposure, only the nucleus accumbens findings survived. There were no significant relationships between experiences of childhood deprivation and amygdala or nucleus accumbens connectivity.

CONCLUSIONS

Experiences of threat are associated with increased nucleus accumbens and amygdala connectivity, which may reflect a preparedness to detect salient and visual stimuli. This may also reflect a propensity toward dysregulated reward processing. Overall, these results suggest that childhood threat may be contributing to aberrant neural baseline reward and threat sensitivity later in life in an adult trauma sample.

The interplay of childhood trauma, oxytocin, and impulsivity in predicting the onset of methamphetamine use

BACKGROUND

Childhood trauma is associated with substance use disorders, including methamphetamine use disorder (MUD). Oxytocin, involved in social bonding, stress regulation, and reward processing, may influence addiction vulnerability and impulsivity in individuals with a history of childhood trauma.

OBJECTIVE

To investigate the relationships among childhood trauma, oxytocin levels, impulsivity, and the age of first methamphetamine use in individuals with MUD.

PARTICIPANTS AND SETTING

The study included 298 male participants (148 individuals with MUD and 150 healthy controls) from both probation offices and psychiatric clinics.

METHODS

Childhood trauma was assessed using the Childhood Trauma Questionnaire-Short Form (CTQ-SF), impulsivity with the Barratt Impulsiveness Scale-11 (BIS-11), and plasma oxytocin levels were obtained.

RESULTS

Individuals with MUD exhibited higher levels of childhood trauma, impulsivity, and lower plasma oxytocin levels compared to healthy controls. Childhood trauma was associated with a younger age of first methamphetamine use, higher impulsivity, and lower oxytocin levels among individuals with MUD. Plasma oxytocin levels partially mediated the relationship between childhood trauma and both the age of first methamphetamine use and impulsivity. Serial mediation analysis demonstrated that oxytocin levels and impulsivity sequentially mediated the relationship between childhood trauma and the age of first methamphetamine use.

CONCLUSIONS

The findings reveal the complex interplay among childhood trauma, oxytocin, impulsivity, and methamphetamine use, emphasizing the importance of considering these factors in prevention and intervention strategies for MUD. Future research should explore oxytocin and impulsivity-focused interventions to mitigate the effects of childhood trauma and reduce MUD development risk.

Mindfulness and clinical correlates in methamphetamine use disorder

BACKGROUND

Mindfulness-based interventions are increasingly used for the treatment of substance use disorders, including methamphetamine use disorder (MUD). Literature indicates that trait mindfulness may play a key role in the effectiveness of these treatments on therapeutic outcome, yet no prior studies have tested for differences in trait mindfulness between individuals with MUD and healthy control participants. Such differences are important for treatment implementation.

OBJECTIVES

The goals of this study were to evaluate trait mindfulness and to determine its clinical correlates in individuals with MUD.

METHODS

A group of participants with MUD at varying lengths of abstinence from methamphetamine (< 1h to 90 days; mean 5.4 ± 12.5 days; N=95, 53 female, 42 male) and a healthy control group (N=65, 30 female, 35 male) completed the Mindfulness Attention Awareness Scale (MAAS). Group differences and relationships between trait mindfulness and several measures of drug use and psychiatric symptoms were evaluated.

RESULTS

In participants with MUD, trait mindfulness was 10% lower than in healthy controls (p < 0.001), but it was not significantly correlated with measures of drug use or craving. Across both groups, trait mindfulness was negatively correlated with state anxiety, depression, emotional dysregulation, impulsivity, and a history of childhood trauma, while it was positively correlated with self-compassion (ps < 0.001).

CONCLUSION

The deficit in trait mindfulness in MUD presents a capacity that can be targeted for improved treatment outcome with mindfulness-based therapies. Trait mindfulness is inversely related to mood dysregulation.

Hyperconnectivity of the lateral amygdala in long-term methamphetamine abstainers negatively correlated with withdrawal duration

Introduction: Several studies have reported structural and functional abnormalities of the amygdala caused by methamphetamine addiction. However, it is unknown whether abnormalities in amygdala function persist in long-term methamphetamine abstainers. Methods: In this study, 38 long-term male methamphetamine abstainers (>12 months) and 40 demographically matched male healthy controls (HCs) were recruited. Considering the heterogeneous nature of the amygdala structure and function, we chose 4 amygdala subregions (i.e., left lateral, left medial, right lateral, and right medial) as regions of interest (ROI) and compared the ROI-based resting-state functional connectivity (FC) at the whole-brain voxel-wise between the two groups. We explored the relationship between the detected abnormal connectivity, methamphetamine use factors, and the duration of withdrawal using correlation analyses. We also examined the effect of methamphetamine use factors, months of withdrawal, and sociodemographic data on detected abnormal connectivity through multiple linear regressions. Results: Compared with HCs, long-term methamphetamine abstainers showed significant hyperconnectivity between the left lateral amygdala and a continuous area extending to the left inferior/middle occipital gyrus and left middle/superior temporal gyrus. Abnormal connections negatively correlated with methamphetamine withdrawal time (r = -0.85, p < 0.001). The linear regression model further demonstrated that the months of withdrawal could identify the abnormal connectivity (βadj = -0.86, 95%CI: -1.06 to -0.65, p < 0.001). Discussion: The use of methamphetamine can impair the neural sensory system, including the visual and auditory systems, but this abnormal connectivity can gradually recover after prolonged withdrawal of methamphetamine. From a neuroimaging perspective, our results suggest that withdrawal is an effective treatment for methamphetamine.

Right amygdala-right precuneus connectivity is associated with childhood trauma in major depression patients and healthy controls

The present study investigated the effect of childhood trauma (CT) on amygdala and hippocampus functional connectivity (FC) and the association with clinical presentations of major depressive disorder (MDD). Participants included 73 MDD patients (42 with moderate-to-severe CT and 31 with no or low CT) and 64 healthy controls (HC; 30 with moderate-to-severe CT and 34 with no or low CT). Seed-based whole-brain resting-state FC analyses were performed with seeds located in amygdala and hippocampus. Individuals with moderate-to-severe CT, irrespective of MDD diagnosis, had decreased right amygdala-right precuneus connectivity compared to those with no or low CT. Right amygdala-right precuneus connectivity was significantly correlated with physical and social trait anhedonia in MDD. Mediation effects of this FC on relationship between CT (specifically neglect but not abuse) and trait anhedonia in MDD were significant. MDD patients demonstrated increased right amygdala-left middle frontal gyrus FC, decreased right amygdala-right medial superior frontal gyrus (mSFG) FC and decreased right hippocampus-bilateral mSFG FC relative to HC. Findings highlight the effect of CT on right amygdala-right precuneus FC irrespective of MDD diagnosis. FC of right amygdala-right precuneus may be involved in the mechanism linking CT and depression through its association with trait anhedonia.

Lack of amygdala habituation to negative emotional faces in alcohol use disorder and the relation to adverse childhood experiences

Aberrant limbic circuit reactivity to negative stimuli might be related to alterations in emotion processing and regulation in alcohol use disorder (AUD). The current study tested for the first time in AUD the hypothesis of aberrant amygdala habituation to repeated aversive stimuli-a robust and reliable neuroimaging marker for emotion processing. We explored the link between deficits in habituation to adverse childhood experience (ACE), a common risk factor for impaired emotion regulation and AUD. AUD individuals (N = 36) and healthy controls (HC; N = 26) participated in an observational case-control functional magnetic resonance imaging (fMRI) study. An established habituation index was used to investigate processing of aversive emotional faces of the amygdala. AUD individuals showed an overall deficit in amygdala habituation (right: t = 4.26, pFWE = 0.004; left: t = 4.79, pFWE ≤ 0.001). Amygdala habituation was significantly related to increased exposure to ACE in HC (t = 3.88, pFWE = 0.012), whereas this association was not observed in AUD individuals (T = 1.80, pFWE = 0.662). Further, a significant association between higher alcohol consumption and reduced amygdala habituation (right: R²  = -0.356, F = 8.736, p = 0.004; left: R²  = -0.309, F = 6.332, p = 0.015) was observed. We found novel evidence for neural alterations in emotion processing in AUD individuals, indexed by deficient amygdala habituation to negative emotional content. We replicated a prior report on a link between ACE and amygdala habituation, a well-established environmental risk factor for mental disorders and emotion dysregulation, in our control sample. Additionally, deficient amygdala habituation related to the amount of alcohol consumption in the overall sample might indicate a short-term substance effect.

Prevalence, demographics, and cognitive dysfunction among methamphetamine-dependent individuals with childhood maltreatment

Previous studies have shown that dependent individuals (DIs) have higher rates of childhood maltreatment and poorer cognitive performance compared with healthy controls. However, little attention has been paid to the cognitive dysfunction of DIs with childhood maltreatment. The purpose of this study was to explore the cognitive deficits of maltreated methamphetamine-dependent individuals (METH-DIs) using a cross-sectional and case-control design. In addition, we aimed to examine the prevalence of childhood maltreatment and the demographic and clinical characteristics of Chinese male METH-DIs. 330 METH-DIs and 143 healthy controls were recruited and completed a detailed questionnaire on demographic and drug-related variables. Childhood abuse data were collected from the Childhood Trauma Questionnaire-Short Form (CTQ-SF). Cognitive function was assessed by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The Beck Depression Inventory, Beck Anxiety Inventory, and Visual Analogue Scale (VAS) were used to assess the clinical state of the METH-DIs. 166 of 326 (50.9%) METH-DIs had experienced at least one type of childhood maltreatment. Maltreated METH-DIs were more likely to have a lower level of education (t₃₂₄ = 5.81, p < 0.001), a higher level of depression(t₃₂₄ = －2.68, p < 0.01), and a younger onset age of drug use (t₃₂₄ = 3.58, p < 0.01) than METH-DIs who had no experience of childhood maltreatment. Maltreated METH-DIs also performed worse on the RBANS attention score than METH-DIs who did not experience maltreatment (F_1,324 = 15.41, p < 0.001, partial η² = 0.05). Our findings revealed that some demographic and clinical variables were associated with maltreatment among METH-DIs. Moreover, attention dysfunction was found in maltreated METH-DIs, which conforms to the theory of latent vulnerability.

Recent Advances in the Understanding of Specific Efferent Pathways Emerging From the Cerebellum

The cerebellum has a long history in terms of research on its network structures and motor functions, yet our understanding of them has further advanced in recent years owing to technical developments, such as viral tracers, optogenetic and chemogenetic manipulation, and single cell gene expression analyses. Specifically, it is now widely accepted that the cerebellum is also involved in non-motor functions, such as cognitive and psychological functions, mainly from studies that have clarified neuronal pathways from the cerebellum to other brain regions that are relevant to these functions. The techniques to manipulate specific neuronal pathways were effectively utilized to demonstrate the involvement of the cerebellum and its pathways in specific brain functions, without altering motor activity. In particular, the cerebellar efferent pathways that have recently gained attention are not only monosynaptic connections to other brain regions, including the periaqueductal gray and ventral tegmental area, but also polysynaptic connections to other brain regions, including the non-primary motor cortex and hippocampus. Besides these efferent pathways associated with non-motor functions, recent studies using sophisticated experimental techniques further characterized the historically studied efferent pathways that are primarily associated with motor functions. Nevertheless, to our knowledge, there are no articles that comprehensively describe various cerebellar efferent pathways, although there are many interesting review articles focusing on specific functions or pathways. Here, we summarize the recent findings on neuronal networks projecting from the cerebellum to several brain regions. We also introduce various techniques that have enabled us to advance our understanding of the cerebellar efferent pathways, and further discuss possible directions for future research regarding these efferent pathways and their functions.

An Exploratory Study on Resting-State Functional Connectivity in Individuals with Disorganized Attachment: Evidence for Key Regions in Amygdala and Hippocampus

Studies comparing organized (O) and unresolved/disorganized (UD) attachment have consistently shown structural and functional brain abnormalities, although whether and how attachment patterns may affect resting state functional connectivity (RSFC) is still little characterized. Here, we investigated RSFC of temporal and limbic regions of interest for UD attachment. Participants’ attachment was classified via the Adult Attachment Interview, and all participants underwent clinical assessment. Functional magnetic resonance imaging data were collected from 11 UD individuals and seven matched O participants during rest. A seed-to-voxel analysis was performed, including the anterior and the posterior cingulate cortex, the bilateral insula, amygdala and hippocampus as seed regions. No group differences in the clinical scales emerged. Compared to O, the UD group showed lower RSFC between the left amygdala and the left cerebellum (lobules VIII), and lower functional coupling between the right hippocampus and the posterior portion of the right middle temporal gyrus. Moreover, UD participants showed higher RSFC between the right amygdala and the anterior cingulate cortex. Our findings suggest RSFC alterations in regions associated with encoding of salient events, emotion processing, memories retrieval and self-referential processing in UD participants, highlighting the potential role of attachment experiences in shaping brain abnormalities also in non-clinical UD individuals.

The interaction of child abuse and rs1360780 of the FKBP5 gene is associated with amygdala resting-state functional connectivity in young adults

Extensive research has demonstrated that rs1360780, a common single nucleotide polymorphism within the FKBP5 gene, interacts with early-life stress in predicting psychopathology. Previous results suggest that carriers of the TT genotype of rs1360780 who were exposed to child abuse show differences in structure and functional activation of emotion-processing brain areas belonging to the salience network. Extending these findings on intermediate phenotypes of psychopathology, we examined if the interaction between rs1360780 and child abuse predicts resting-state functional connectivity (rsFC) between the amygdala and other areas of the salience network. We analyzed data of young European adults from the general population (N = 774; mean age = 18.76 years) who took part in the IMAGEN study. In the absence of main effects of genotype and abuse, a significant interaction effect was observed for rsFC between the right centromedial amygdala and right posterior insula (p < .025, FWE-corrected), which was driven by stronger rsFC in TT allele carriers with a history of abuse. Our results suggest that the TT genotype of rs1360780 may render individuals with a history of abuse more vulnerable to functional changes in communication between brain areas processing emotions and bodily sensations, which could underlie or increase the risk for psychopathology.

The Effect of Early Life Stress on Memory is Mediated by Anterior Hippocampal Network

The experience of early life stress (ELS) is a risk factor for memory dysfunction, but the impact at the neural level is less clear. The aim of this study is to investigate whether healthy people with a higher ELS display more structural and functional changes of hippocampus than people with a lower ELS, and to investigate whether hippocampus changes in turn affects memory. The Childhood Trauma Questionnaire (CTQ) was used to assess ELS in 100 young health participants. They were divided into two groups: "low" CTQ group (limitation of none/minimal ELS) and "high" CTQ group (low to moderate ELS). Verbal memory was assessed by California Verbal Learning Test II and visual memory by Rey-Osterrieth Complex Figure. Resting state fMRI data were acquired and voxel-wise correlation analysis was performed to functionally divide the hippocampus. Gray matter volumes and memory circuits of the anterior and posterior hippocampus were analyzed. We also tested whether changes in hippocampus mediated the relationship between ELS and memory. Compared with participants with a lower ELS, healthy participants with a relatively higher ELS had reduced anterior hippocampal functional connectivity, which positively correlated with visual memory. Among all participants, anterior hippocampal functional connectivity mediated the relationship of ELS on visual memory. These findings suggest that ELS decreased anterior hippocampal-cortical functional connectivity, which, in turn, drives memory decline and highlight a potential pathway in which ELS affects memory by degrading anterior hippocampal functional connectivity changes directly.

Brain networks underlying vulnerability and resilience to drug addiction

Resting-state functional connectivity provides novel insight into variations in neural networks associated with addiction to stimulant drugs in individuals with and without a family history of addiction, and both with and without personal drug use. An increased risk for addiction, either because of drug use or genetic/psychosocial vulnerability, is associated with hypoconnectivity in frontostriatal networks, which may weaken goal-directed decision-making. Resilience against addiction development, by contrast, is characterized by hyperconnectivity in two corticostriatal pathways, possibly reflecting compensatory responses in networks associated with regulatory control over habitual behaviors. It is thus conceivable that defying the risk of developing stimulant drug addiction requires increased efforts to control behavior—a hypothesis that may open up new pathways for therapeutic and preventative strategies.

Regular drug use can lead to addiction, but not everyone who takes drugs makes this transition. How exactly drugs of abuse interact with individual vulnerability is not fully understood, nor is it clear how individuals defy the risks associated with drugs or addiction vulnerability. We used resting-state functional MRI (fMRI) in 162 participants to characterize risk- and resilience-related changes in corticostriatal functional circuits in individuals exposed to stimulant drugs both with and without clinically diagnosed drug addiction, siblings of addicted individuals, and control volunteers. The likelihood of developing addiction, whether due to familial vulnerability or drug use, was associated with significant hypoconnectivity in orbitofrontal and ventromedial prefrontal cortical-striatal circuits—pathways critically implicated in goal-directed decision-making. By contrast, resilience against a diagnosis of substance use disorder was associated with hyperconnectivity in two networks involving 1) the lateral prefrontal cortex and medial caudate nucleus and 2) the supplementary motor area, superior medial frontal cortex, and putamen—brain circuits respectively implicated in top-down inhibitory control and the regulation of habits. These findings point toward a predisposing vulnerability in the causation of addiction, related to impaired goal-directed actions, as well as countervailing resilience systems implicated in behavioral regulation, and may inform novel strategies for therapeutic and preventative interventions.

Dark Times: The Role of Negative Reinforcement in Methamphetamine Addiction

Methamphetamine use is associated with substantial adverse outcomes including poor mental and physical health, financial difficulties, and societal costs. Despite deleterious long-term consequences associated with methamphetamine, many people use drugs for short-term reduction of unpleasant physical or emotional sensations. By removing these aversive states, drug use behaviors are negatively reinforced. Abstinence from methamphetamine can then result in a return to previous aversive emotional states linked to withdrawal and craving, often contributing to an increased likelihood for relapse. This negative reinforcement cycle is hypothesized to be a motivating and maintaining factor for addiction. Thus, this review highlights the current evidence for negative reinforcement mechanisms in methamphetamine use disorder by integrating studies of subjective experience, behavior, functional magnetic resonance imaging, positron emission tomography, and event-related potentials and examining the efficacy of treatments targeting aspects of negative reinforcement. Overall, the literature demonstrates that individuals who use methamphetamine have diminished cognitive control and process emotions, loss of reward, and interoceptive information differently than non-using individuals. These differences are reflected in behavioral and subjective experiments as well as brain-based experiments which report significant differences in various frontal regions, insula, anterior cingulate cortex, and striatum. Together, the results suggest methamphetamine users have an altered experience of negative outcomes, difficulties employing effective emotion regulation, and difficulty engaging in adaptive or goal-directed decision-making. Suggestions for future research to improve our understanding of how negative reinforcement contributes to methamphetamine addiction and to develop effective interventions are provided.

The Moderating Effects of Sex on Consequences of Childhood Maltreatment: From Clinical Studies to Animal Models

Stress has pronounced effects on the brain, and thus behavioral outputs. This is particularly true when the stress occurs during vulnerable points in development. A review of the clinical literature regarding the moderating effects of sex on psychopathology in individuals exposed to childhood maltreatment (CM) is complicated by a host of variables that are difficult to quantify and control in clinical settings. As a result, the precise role of sex in moderating the consequences of CM remains elusive. In this review, we explore the rationale for studying this important question and their implications for treatment. We examine this issue using the threat/deprivation conceptual framework and highlight a growing body of work demonstrating important sex differences in human studies and in animal models of early life stress (ELS). The challenges and obstacles for effectively studying this question are reviewed and are followed by recommendations on how to move forward at the clinical and preclinical settings. We hope that this review will help inspire additional studies on this important topic.

The cerebellum under stress

Stress-related psychiatric conditions are one of the main causes of disability in developed countries. They account for a large portion of resource investment in stress-related disorders, become chronic, and remain difficult to treat. Research on the neurobehavioral effects of stress reveals how changes in certain brain areas, mediated by a number of neurochemical messengers, markedly alter behavior. The cerebellum is connected with stress-related brain areas and expresses the machinery required to process stress-related neurochemical mediators. Surprisingly, it is not regarded as a substrate of stress-related behavioral alterations, despite numerous studies that show cerebellar responsivity to stress. Therefore, this review compiles those studies and proposes a hypothesis for cerebellar function in stressful conditions, relating it to stress-induced psychopathologies. It aims to provide a clearer picture of stress-related neural circuitry and stimulate cerebellum-stress research. Consequently, it might contribute to the development of improved treatment strategies for stress-related disorders.

Neuroinflammation in addiction: A review of neuroimaging studies and potential immunotherapies

Addiction is a worldwide public health problem and this article reviews scientific advances in identifying the role of neuroinflammation in the genesis, maintenance, and treatment of substance use disorders. With an emphasis on neuroimaging techniques, this review examines human studies of addiction using positron emission tomography to identify binding of translocator protein (TSPO), which is upregulated in reactive glial cells and activated microglia during pathological states. High TSPO levels have been shown in methamphetamine use but exhibits variable patterns in cocaine use. Alcohol and nicotine use, however, are associated with lower TSPO levels. We discuss how mechanistic differences at the neurotransmitter and circuit level in the neural effects of these agents and subsequent immune response may explain these observations. Finally, we review the potential of anti-inflammatory drugs, including ibudilast, minocycline, and pioglitazone, to ameliorate the behavioral and cognitive consequences of addiction.

Enhancing the Utility of Preclinical Research in Neuropsychiatry Drug Development

Most large pharmaceutical companies have downscaled or closed their clinical neuroscience research programs in response to the low clinical success rate for drugs that showed tremendous promise in animal experiments intended to model psychiatric pathophysiology. These failures have raised serious concerns about the role of preclinical research in the identification and evaluation of new pharmacotherapies for psychiatry. In the absence of a comprehensive understanding of the neurobiology of psychiatric disorders, the task of developing "animal models" seems elusive. The purpose of this review is to highlight emerging strategies to enhance the utility of preclinical research in the drug development process. We address this issue by reviewing how advances in neuroscience, coupled with new conceptual approaches, have recently revolutionized the way we can diagnose and treat common psychiatric conditions. We discuss the implications of these new tools for modeling psychiatric conditions in animals and advocate for the use of systematic reviews of preclinical work as a prerequisite for conducting psychiatric clinical trials. We believe that work in animals is essential for elucidating human psychopathology and that improving the predictive validity of animal models is necessary for developing more effective interventions for mental illness.

Associations of childhood maltreatment with subsequent illicit drug use among Chinese adolescents: The moderating role of the child's sex

Adolescence is a critical period for the onset of illicit drug use. This study aimed to estimate the prevalence of illicit drug use among Chinese adolescents, to assess the associations between different forms of childhood maltreatment and subsequent illicit drug use and to test whether the child's sex plays a moderating role in the associations. A secondary analysis was made of cross-sectional data collected from 10th to 12th graders from China who were sampled in the 2015 School-based Chinese Adolescents Health Survey. A total of 59,518 questionnaires were included in the final analysis. The prevalence estimates and logistic regression analyses were weighted to account for the complex survey design. If the interaction term (between childhood maltreatment and sex) was significantly associated with illicit drug use, we would perform stratification analyses across sex. Of the total sample, 45.2% were boys, and the mean (SD) age was 17.0 (0.9) years. The results of stratification analyses demonstrated that among boys, physical abuse and sexual abuse were independently associated with an increased risk of use during their lifetime of MDMA, methamphetamine, ketamine, and mephedrone; among girls, only emotional abuse and sexual abuse were associated with MDMA use, methamphetamine use, ketamine use, and mephedrone use.

A preliminary randomized clinical trial of naltrexone reduces striatal resting state functional connectivity in people with methamphetamine use disorder

OBJECTIVE

Naltrexone has been shown to attenuate craving and the subjective effects of methamphetamine. Although naltrexone has modulatory effects on neural activity at dopaminergic synapses, the effect on striatal connectivity is unclear. As methamphetamine use is associated with greater resting-state functional connectivity (RSFC) in the dopaminergic system, we examined whether extended-release naltrexone (XR-NTX) can normalize striatal connectivity and whether changes in RSFC are associated with changes in craving and methamphetamine use.

METHODS

Thirty-seven participants in or seeking treatment for methamphetamine use disorder took part in this clinical trial at a university-based research clinic between May 2013 and March 2015 (Clinicaltrials.gov NCT01822132). Participants were randomized by a random number generator to a single four-week injection of XR-NTX or placebo. Functional magnetic resonance imaging (fMRI) and self-reported measures of craving and methamphetamine use were conducted before and after double-blinded randomization.

FINDINGS

There was a significant reduction in methamphetamine use in the naltrexone group and a significant treatment-by-time interaction on RSFC between the ventral striatum, amygdala, hippocampus, and midbrain. Connectivity was significantly reduced over time in participants randomized to naltrexone but unchanged in those randomized to placebo (p < 0.05, whole-brain corrected). Interactions between treatment and changes in connectivity show that significant reductions in connectivity were associated with reductions in methamphetamine use.

CONCLUSIONS

Neurobiological deficits associated with methamphetamine use may undermine the efficacy of pharmacotherapies that directly target the dopamine reward system. Naltrexone, via antagonism of indirect mu-opioid effects on dopamine neurons, may attenuate reward system connectivity and aid in methamphetamine use treatment.

Community violence exposure in early adolescence: Longitudinal associations with hippocampal and amygdala volume and resting state connectivity

Community violence exposure is a common stressor, known to compromise youth cognitive and emotional development. In a diverse, urban sample of 22 adolescents, participants reported on community violence exposure (witnessing a beating or illegal drug use, hearing gun shots, or other forms of community violence) in early adolescence (average age 12.99), and underwent a neuroimaging scan 3-5 years later (average age 16.92). Community violence exposure in early adolescence predicted smaller manually traced left and right hippocampal and amygdala volumes in a model controlling for age, gender, and concurrent community violence exposure, measured in late adolescence. Community violence continued to predict hippocampus (but not amygdala) volumes after we also controlled for family aggression exposure in early adolescence. Community violence exposure was also associated with stronger resting state connectivity between the right hippocampus (using the manually traced structure as a seed region) and bilateral frontotemporal regions including the superior temporal gyrus and insula. These resting state connectivity results held after controlling for concurrent community violence exposure, SES, and family aggression. Although this is the first study focusing on community violence in conjunction with brain structure and function, these results dovetail with other research linking childhood adversity with smaller subcortical volumes in adolescence and adulthood, and with altered frontolimbic resting state connectivity. Our findings suggest that even community-level exposure to neighborhood violence can have detectable neural correlates in adolescents.

The relationship between interleukin-6 and functional connectivity in methamphetamine users

Methamphetamine (MA) causes an increase in pro-inflammatory cytokines in animal models and in humans. Resulting activation of microglia and neuro-inflammation could, via effects on reward networks, mediate behavioral characteristics of addiction. We examined the relationship between interleukin-6 (IL-6) and corticolimbic and striatolimbic resting-state functional connectivity (RSFC). Thirty adults diagnosed with MA dependence and 20 control subjects underwent a resting-state functional magnetic resonance imaging (fMRI) scan and gave a blood sample for determination of plasma IL-6 levels. Seed-based RSFC analyses were performed to examine the interactive effect of group and IL-6 on ventral striatal and prefrontal connectivity. Within the MA group, IL-6 levels were positively related to striatolimbic RSFC but negatively related to corticostriatal RSFC. Our findings with IL-6 support the idea that inflammation may at least partly mediate the link among MA use disorder, RSFC, and behavior, possibly via effects on mesolimbic and mesocortical dopaminergic systems.

Longitudinal Associations Between Family Aggression, Externalizing Behavior, and the Structure and Function of the Amygdala

Using longitudinal data from 21 adolescents, we assessed family aggression (via mother, father, and youth report) in early adolescence, externalizing behavior in mid-adolescence, and magnetic resonance imaging (MRI) data in late adolescence. Amygdalae were manually traced, and used as seed regions for resting state analyses. Both family aggression and subsequent externalizing behavior predicted larger right amygdala volumes and stronger amygdala-frontolimbic/salience network connectivity and weaker amygdala-posterior cingulate connectivity. Externalizing behavior in mid-adolescence mediated associations between family aggression in early adolescence and resting state connectivity between the amygdala and the subgenual anterior cingulate cortex, medial prefrontal cortex, orbitofrontal cortex, and posterior cingulate cortex in late adolescence. Family adversity and adolescent behavior problems may share common neural correlates.

Amygdala hyper-connectivity in a mouse model of unpredictable early life stress

Childhood maltreatment is associated with a wide range of psychopathologies including anxiety that emerge in childhood and in many cases persist in adulthood. Increased amygdala activation in response to threat and abnormal amygdala connectivity with frontolimbic brain regions, such as the hippocampus and the prefrontal cortex, are some of the most consistent findings seen in individuals exposed to childhood maltreatment. The underlying mechanisms responsible for these changes are difficult to study in humans but can be elucidated using animal models of early-life stress. Such studies are especially powerful in the mouse where precise control of the genetic background and the stress paradigm can be coupled with resting-state fMRI (rsfMRI) to map abnormal connectivity in circuits that regulate anxiety. To address this issue we first compared the effects of two models of early-life stress, limited bedding (LB) and unpredictable postnatal stress (UPS), on anxiety-like behavior in juvenile and adult mice. We found that UPS, but not LB, causes a robust increase in anxiety in juvenile and adult male mice. Next, we used rsfMRI to compare frontolimbic connectivity in control and UPS adult male mice. We found increased amygdala-prefrontal cortex and amygdala-hippocampus connectivity in UPS. The strength of the amygdala-hippocampal and amygdala-prefrontal cortex connectivity was highly correlated with anxiety-like behavior in the open-field test and elevated plus maze. These findings are the first to link hyperconnectivity in frontolimbic circuits and increased anxiety in a mouse model of early-life stress, allowing for more mechanistic understanding of parallel findings in humans.

Distinct intrinsic functional brain network abnormalities in methamphetamine-dependent patients with and without a history of psychosis

Chronic methamphetamine use is associated with executive functioning deficits that suggest dysfunctional cognitive control networks (CCNs) in the brain. Likewise, abnormal connectivity between intrinsic CCNs and default mode networks (DMNs) has also been associated with poor cognitive function in clinical populations. Accordingly, we tested the extent to which methamphetamine use predicts abnormal connectivity between these networks, and whether, as predicted, these abnormalities are compounded in patients with a history of methamphetamine-associated psychosis (MAP). Resting-state fMRI data were acquired from 46 methamphetamine-dependent patients [19 with MAP, 27 without (MD)], as well as 26 healthy controls (CTRL). Multivariate network modelling and whole-brain voxel-wise connectivity analyses were conducted to identify group differences in intrinsic connectivity across four cognitive control and three DMN networks identified using an independent components analysis approach (meta-ICA). The relationship of network connectivity and psychotic symptom severity, as well as antipsychotic treatment and methamphetamine use variables, was also investigated. Robust evidence of hyper-connectivity was observed between the right frontoparietal and anterior DMN networks in MAP patients, and 'normalized' with increased duration of treatment with antipsychotics. Attenuation of anticorrelated anterior DMN-dorsal attention network activity was also restricted to this group. Elevated coupling detected in MD participants between anterior and posterior DMN networks became less apparent with increasing duration of abstinence from methamphetamine. In summary, we observed both alterations of RSN connectivity between DMN networks with chronic methamphetamine exposure, as well as DMN-CCN coupling abnormalities consistent with possible MAP-specific frontoparietal deficits in the biasing of task-appropriate network activity.

A Multimodal Study of Childhood Trauma and Distress Tolerance in Young Adulthood

Individuals with a history of childhood trauma experience deficits in emotion regulation. However, few studies have investigated childhood trauma and both perceived (i.e., self-report) and behavioral measures of distress tolerance. The current study evaluated associations between childhood trauma (i.e., physical abuse, sexual abuse, and witnessing family violence) and measures of perceived (Distress Tolerance Scale) and behavioral distress tolerance (i.e., Paced Auditory Serial Addition Test, breath-holding). Participants were 320 undergraduate students with a history of interpersonal trauma (e.g., sexual/physical assault). Structural equation modeling was used to evaluate associations between frequency of childhood trauma type and distress tolerance. Greater childhood physical abuse was associated with higher perceived distress tolerance. Greater levels of witnessing family violence were associated with lower behavioral distress tolerance on the breath-holding task. No significant effects were found for Paced Auditory Serial Addition Test performance. Associations between childhood trauma and emotion regulation likely are complex and warrant further study.

Effects of social and spatial contexts on young latinas' methamphetamine use initiation

In this article, we examine methamphetamine (meth) use initiation as influenced by Latinas' social positions within institutions (e.g., family and economy). We conducted ethnographic fieldwork in five women's residential substance use treatment facilities in Los Angeles County with women who considered meth to be their primary drug of choice. Using an urban ethnographic framing, we demonstrate the effects of low-income young Latinas' spatial- and social-context rendered vulnerability to abuse and neglect, and the resulting emotional distress, on meth use initiation. When considering pathways to substance use intervention for vulnerable Latina girls and women, clinicians, researchers, and policy makers need to understand substance use pathways as dynamic processes to cope with psychosocial stress while living in communities with easy access to illicit substances such as methamphetamine.

Utility of the cumulative stress and mismatch hypotheses in understanding the neurobiological impacts of childhood abuse and recent stress in youth with emerging mental disorder

Childhood abuse has an enduring impact on the brain's stress system. Whether the effects of childhood abuse and adulthood stress are additive (cumulative stress hypothesis) or interactive (mismatch hypothesis) is widely disputed, however. The primary aim of this study was to test the utility of the cumulative stress and mismatch hypotheses in understanding brain and behaviour. We recruited 64 individuals (aged 14-26) from a specialised clinic for assessment and early intervention of mental health problems in young people. A T1-weighted MRI, a resting state fMRI and clinical assessment were acquired from each participant. Grey matter estimates and resting state functional connectivity (rsFC) of the hippocampus, amygdala and anterior cingulate cortex (ACC) were determined using segmentation and seed-to-voxel rsFC analyses. We explored the effects of childhood abuse and recent stress on the structure and function of the regions of interest within general linear models. Worse psychiatric symptoms were significantly related to higher levels of life time stress. Individuals with mismatched childhood and recent stress levels had reduced left hippocampal volume, reduced ACC-ventrolateral prefrontal cortex rsFC and greater ACC-hippocampus rsFC, compared to individuals with matched childhood and recent stress levels. These results show specific utility of the cumulative stress hypothesis in understanding psychiatric symptomatology and of the mismatch hypothesis in modelling hippocampal grey matter, prefrontal rsFC, and prefrontal-hippocampal rsFC. We provide novel evidence for the enduring impact of childhood abuse on stress reactivity in a clinical population, and demonstrate the distinct effects of stress in different systems. Hum Brain Mapp 38:2709-2721, 2017. © 2017 Wiley Periodicals, Inc.

Effects of naltrexone are influenced by childhood adversity during negative emotional processing in addiction recovery

Naltrexone is an opioid receptor antagonist used in the management of alcohol dependence. Although the endogenous opioid system has been implicated in emotion regulation, the effects of mu-opioid receptor blockade on brain systems underlying negative emotional processing are not clear in addiction. Individuals meeting criteria for alcohol dependence alone (n=18, alcohol) and in combination with cocaine and/or opioid dependence (n=21, alcohol/drugs) and healthy individuals without a history of alcohol or drug dependence (n=21) were recruited. Participants were alcohol and drug abstinent before entered into this double-blind, placebo-controlled, randomized, crossover study. Functional magnetic resonance imaging was used to investigate brain response while viewing aversive and neutral images relative to baseline on 50 mg of naltrexone and placebo. We found that naltrexone modulated task-related activation in the medial prefrontal cortex and functional connectivity between the anterior cingulate cortex and the hippocampus as a function of childhood adversity (for aversive versus neutral images) in all groups. Furthermore, there was a group-by-treatment-by-condition interaction in the right amygdala, which was mainly driven by a normalization of response for aversive relative to neutral images under naltrexone in the alcohol/drugs group. We conclude that early childhood adversity is one environmental factor that influences pharmacological response to naltrexone. Pharmacotherapy with naltrexone may also have some ameliorative effects on negative emotional processing in combined alcohol and drug dependence, possibly due to alterations in endogenous opioid transmission or the kappa-opioid receptor antagonist actions of naltrexone.

Developmental stress elicits preference for methamphetamine in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder

BACKGROUND

Developmental stress has been hypothesised to interact with genetic predisposition to increase the risk of developing substance use disorders. Here we have investigated the effects of maternal separation-induced developmental stress using a behavioural proxy of methamphetamine preference in an animal model of attention-deficit/hyperactivity disorder, the spontaneously hypertensive rat, versus Wistar Kyoto and Sprague-Dawley comparator strains.

RESULTS

Analysis of results obtained using a conditioned place preference paradigm revealed a significant strain × stress interaction with maternal separation inducing preference for the methamphetamine-associated compartment in spontaneously hypertensive rats. Maternal separation increased behavioural sensitization to the locomotor-stimulatory effects of methamphetamine in both spontaneously hypertensive and Sprague-Dawley strains but not in Wistar Kyoto rats.

CONCLUSIONS

Our findings indicate that developmental stress in a genetic rat model of attention-deficit/hyperactivity disorder may foster a vulnerability to the development of substance use disorders.

Emotion dysregulation and amygdala dopamine D2-type receptor availability in methamphetamine users

BACKGROUND

Individuals who use methamphetamine chronically exhibit emotional and dopaminergic neurochemical deficits. Although the amygdala has an important role in emotion processing and receives dopaminergic innervation, little is known about how dopamine transmission in this region contributes to emotion regulation. This investigation aimed to evaluate emotion regulation in subjects who met DSM-IV criteria for methamphetamine dependence, and to test for a relationship between self-reports of difficulty in emotion regulation and D2-type dopamine receptor availability in the amygdala.

METHOD

Ninety-four methamphetamine-using and 102 healthy-control subjects completed the Difficulties in Emotion Regulation Scale (DERS); 33 of those who used methamphetamine completed the Addiction Severity Index (ASI). A subset of 27 methamphetamine-group and 20 control-group subjects completed positron emission tomography with [(18)F]fallypride to assay amygdala D2-type dopamine receptor availability, measured as binding potential (BPND).

RESULTS

The methamphetamine group scored higher than the control group on the DERS total score (p<0.001), with DERS total score positively correlated with the Drug Composite Score on the ASI (p=0.02) in the methamphetamine group. The DERS total score was positively correlated with amygdala BPND in both groups and the combined group of participants (combined: r=0.331, p=0.02), and the groups did not differ in this relationship.

CONCLUSION

These findings highlight problems with emotion regulation linked to methamphetamine use, possibly contributing to personal and interpersonal behavioral problems. They also suggest that D2-type dopamine receptors in the amygdala contribute to emotion regulation in both healthy and methamphetamine-using subjects.

Long-term consequences of childhood maltreatment: Altered amygdala functional connectivity

Childhood maltreatment is a serious individual, familial, and societal threat that compromises healthy development and is associated with lasting alterations to emotion perception, processing, and regulation (Cicchetti & Curtis, 2005; Pollak, Cicchetti, Hornung, & Reed, 2000; Pollak & Tolley-Schell, 2003). Individuals with a history of maltreatment show altered structural and functional brain development in both frontal and limbic structures (Hart & Rubia, 2012). In particular, previous research has identified hyperactive amygdala responsivity associated with childhood maltreatment (e.g., Dannlowski et al., 2012). However, less is known about the impact of maltreatment on the relationship between the amygdala and other brain regions. The present study employed an emotion processing functional magnetic resonance imaging task to examine task-based activation and functional connectivity in adults who experienced maltreatment as children. The sample included adults with a history of substantiated childhood maltreatment (n = 33) and comparison adults (n = 38) who were well matched on demographic variables, all of whom have been studied prospectively since childhood. The maltreated group exhibited greater activation than comparison participants in the prefrontal cortex and basal ganglia. In addition, maltreated adults showed increased amygdala connectivity with the hippocampus and prefrontal cortex. The results suggest that the intense early stress of childhood maltreatment is associated with lasting alterations to frontolimbic circuitry.

The implications of sleep disruption for cognitive and affective processing in methamphetamine abuse

Sleep is disrupted during active use of methamphetamine (MA), during withdrawal from the drug, and during abstinence from its use. However, relatively little is known about possible mediatory functions of disrupted sleep in the emergence, manifestation, and maintenance of cognitive and affective symptoms of MA abuse. We hypothesise that sleep functions as a mediator for stimulant drug effects. Specifically, we propose that objectively-measured sleep parameters can be used to explain some of the variability in the experience and presentation of memory deficits and emotion dysregulation in MA abusers. After describing how important healthy sleep is to unimpaired cognitive and affective functioning, we review literature describing how sleep is disrupted in MA abuse. Then, we provide a conceptual framework for our hypothesis by explaining the relationship between MA abuse, sleep disruption, memory deficits, emotion dysregulation, and changes in reward-related brain networks. We conclude by discussing implications of the hypothesis for research and treatment.

Psychological distress and stressful life events in pediatric complex regional pain syndrome

BACKGROUND

There is little knowledge regarding the association between psychological factors and complex regional pain syndrome (CRPS) in children. Specifically, it is not known which factors precipitate CRPS and which result from the ongoing painful disease.

OBJECTIVES

To examine symptoms of depression and anxiety as well as the experience of stressful life events in children with CRPS compared with children with chronic primary headaches and functional abdominal pain.

METHODS

A retrospective chart study examined children with CRPS (n=37) who received intensive inpatient pain treatment between 2004 and 2010. They were compared with two control groups (chronic primary headaches and functional abdominal pain; each n=37), who also received intensive inpatient pain treatment. Control groups were matched with the CRPS group with regard to admission date, age and sex. Groups were compared on symptoms of depression and anxiety as well as stressful life events.

RESULTS

Children with CRPS reported lower anxiety and depression scores compared with children with abdominal pain. A higher number of stressful life events before and after the onset of the pain condition was observed for children with CRPS.

CONCLUSIONS

Children with CRPS are not particularly prone to symptoms of anxiety or depression. Importantly, children with CRPS experienced more stressful life events than children with chronic headaches or abdominal pain. Prospective long-term studies are needed to further explore the potential role of stressful life events in the etiology of CRPS.