Childhood adversities as specific contributors to the co-occurrence of posttraumatic stress and alcohol use disorders

Effects of early social isolation and adolescent single prolonged stress on anxiety-like behaviors and voluntary ethanol consumption in female Long Evans rats

BACKGROUND

Exposure to stress during childhood and adolescence is a risk factor for alcohol use disorder (AUD) and comorbid conditions, including posttraumatic stress disorder (PTSD). We previously established an adolescent social isolation (SI) model that leads to the emergence of a wide range of behavioral risk factors for AUD, including increased anxiety-like behavior, locomotor activity, and ethanol consumption in male and female rats. Here, we sought to test the hypothesis that SI may increase vulnerability to single prolonged stress (SPS), a rodent model of PTSD.

METHODS

Female Long Evans rats (n = 8/group) were either single-housed or group-housed (GH) (4/cage) on postnatal day 21. One week later, rats underwent testing in the open field test (OFT), elevated plus-maze (EPM), and successive alleys test (SAT). Following initial behavioral testing, a subset of SI/GH rats were exposed to SPS. All rats were then tested on the novelty-suppressed feeding test (NSFT) followed by fear conditioning and home cage two-bottle choice to assess ethanol consumption.

RESULTS

SI significantly increased activity in the OFT and anxiety-like behavior on the SAT, but not the EPM. While SI and SPS alone had no effect on the NSFT, exposure to both stressors significantly increased approach latency. Complex effects of stress history were observed across a 3-day fear conditioning paradigm and no group differences were observed with home cage ethanol consumption, regardless of prior ethanol exposure.

CONCLUSIONS

The results from this study provide novel evidence that SI interacts with SPS in female rats to influence behavior in assays of unconditioned anxiety-like behavior (NSFT) and conditioned fear. Surprisingly, stress exposure had no effect on home cage ethanol consumption. Ultimately, these models provide useful avenues to examine the interaction between stressful experiences, alcohol exposure, biological sex, and the neurobiological adaptations underlying potential risk factors for psychiatric conditions.

Sexually dimorphic effects of a modified adolescent social isolation paradigm on behavioral risk factors of alcohol use disorder in Long Evans Rats

Early life stress (ELS) is a major risk factor for alcohol use disorder (AUD) and comorbid neuropsychiatric conditions. We previously demonstrated that an adolescent social isolation (aSI) model of ELS significantly increased behavioral risk factors for these disorders (e.g. anxiety-like behaviors, alcohol drinking) in male, but not female rats. Since many neurodevelopmental milestones are accelerated in females, we investigated whether an earlier/shorter isolation window (PND 21-38) would yield comparable phenotypes in both sexes. In two experiments, Long Evans rats were socially isolated (SI) or group-housed (GH) on postnatal day (PND) 21 and locomotion was assessed in the open field test (OFT; PND 30). Experiment 1 also assessed behavior on the elevated plus-maze (EPM) (PND 32). In Experiment 2, all rats were single housed on PND 38 to assess home cage alcohol drinking. Experiment 1 revealed that SI females had increased locomotor activity in the OFT but did not differ from GH subjects on the EPM. The OFT results were replicated in both sexes in Experiment 2 and both male and female SI rats had significantly greater ethanol consumption during an eight day continuous access paradigm. In contrast, during subsequent intermittent two-bottle choice drinking, only SI females displayed greater ethanol intake and preference and increased consumption of a quinine-adulterated alcohol solution. These findings demonstrate that early life social isolation can promote AUD vulnerability-related phenotypes in female rats but that there are profound sex differences in the vulnerability window to this early life stressor. Uncovering the neural mechanisms responsible for these sexually dimorphic differences in sensitivity to ELS may shed light on the biological substrates associated with vulnerability to AUD and comorbid disorders of negative emotion in men and women.

[Comorbidity of posttraumatic stress disorder and addiction from a biopsychosocial perspective]

Posttraumatic stress disorder and substance use disorder often co-occur within the health care system. Their comorbidity is associated with more serious acute clinical symptomatology, more frequent hospital admissions in state of emergency and significantly lower chances of improvement by psychological and pharmacological treatment. Their comorbidity contributes to dramatically unfavourable courses of illness as regards all biopsychosocial levels. The survey presented will discuss empirical findings from various perspectives: general epidemiology, substance use disorder as risk factor of trauma and PTSD, trauma and PTSD as risk factor of SUD, neurobiological effects of SUD converging towards neurobiology of PTSD, shared common factors of genetics/epigenetics, personality traits, and early developmental stress and trauma. The main focus of analysis will be put on processes that are intrinsically linked to the development and course of both disorders.

Childhood adversity patterns differentially cluster with mental disorders and socioeconomic indicators in a large Swiss community sample

BACKGROUND

Exposure to childhood adversities (CHAD) has been found to be strongly associated with individuals' mental health and social development. Recently, it has been suggested that certain CHAD patterns exist in the population, which are more closely related to individuals' later mental health than the simple summation of adversities. The current study aims 1) to establish CHAD patterns based on self-reported child abuse and family dysfunction and 2) to assess their associations with mental disorders and sociodemographic indicators reported in adulthood.

METHODS

Data used in this cross-sectional study were derived from the representative CoLaus/PsyCoLaus population-based cohort (N = 5111, 35 to 88 years). Latent class analysis was conducted for the identification of CHAD patterns, while their associations with mental disorders and socioeconomic achievements (e. g. education and income) were investigated using correspondence analysis.

RESULTS

Four CHAD patterns emerged. While the majority (70.7%) of the sample showed an overall low adversity pattern (c1), 13.6% had not been raised by both of their biological parents due to divorce or being placed in foster home (c2), 11.0% had been raised by conflictive / dysfunctional / abusive parents (c3), and 4.7% showed high overall adversities (c4). Patterns c3 and c4 were most strongly associated with various mental disorders, especially c3 with internalizing anxiety disorders, while c2 was closely related to lower educational achievement.

CONCLUSIONS

Four CHAD patterns characterised by varying levels of child abuse and family dysfunction existed in this community sample. They yielded distinct associations with mental disorders and socioeconomic indicators.

Nerve Growth Factor, Stress and Diseases

Stress is a constant threat for homeostasis and is represented by different extrinsic and intrinsic stimuli (stressors, Hans Selye's "noxious agents"), such as aggressive behavior, fear, diseases, physical activity, drugs, surgical injury, and environmental and physiological changes. Our organisms respond to stress by activating the adaptive stress system to activate compensatory responses for restoring homeostasis. Nerve Growth Factor (NGF) was discovered as a signaling molecule involved in survival, protection, differentiation, and proliferation of sympathetic and peripheral sensory neurons. NGF mediates stress with an important role in translating environmental stimuli into physiological and pathological feedbacks since NGF levels undergo important variations after exposure to stressful events. Psychological stress, lifestyle stress, and oxidative stress are well known to increase the risk of mental disorders such as schizophrenia, major depressive disorders, bipolar disorder, alcohol use disorders and metabolic disorders such as metabolic syndrome. This review reports recent works describing the activity of NGF in mental and metabolic disorders related to stress.

Early life stress induces hyperactivity but not increased anxiety-like behavior or ethanol drinking in outbred heterogeneous stock rats

Early life stress is known to impact vulnerability to psychopathological disorders in adulthood, including anxiety and alcohol use disorder (AUD), but the mechanisms underlying susceptibility to these outcomes are not fully understood. In the current study, we used adolescent social isolation (ASI) to determine whether Heterogeneous Stock (HS) rats, an outbred model used for genetic fine-mapping, could be used to study the genetics contributing to ASI-induced anxiety- and AUD-like behavior. We isolated (ASI) or group-housed (adolescent group-housed; AGH) 64 male HS rats at 4 weeks of age. After 5 weeks in these housing conditions, multiple anxiety and coping/despair-like behaviors were measured. All rats were then individually housed and assessed for voluntary ethanol self-administration. At euthanasia, synaptoneurosomes were isolated from a subset of brains to examine the expression of two proteins associated with alcohol drinking-related behaviors, GluA1 and SK2, in the dorsal (dHC) and ventral hippocampus (vHC). We found that ASI increased hyperactivity in the open field test relative to AGH, with no changes in other anxiety-like behaviors. Surprisingly, ASI rats demonstrated decreased immobility and increased climbing in the forced swim test relative to AGH. In contrast to prior studies by us and others, we found no difference in self-administration of 20% ethanol, with decreased ethanol self-administration in ASI relative to AGH rats at higher ethanol concentrations. Furthermore, while ASI in Long-Evans rats resulted in decreased SK2 expression in vHC synaptosomes, no differences were seen in vHC synaptosomes for SK2 or GluA1 in HS rats. These results demonstrate that HS rats are protected against many of the negative effects previously seen in response to ASI, namely anxiety-like behavior and increased ethanol self-administration. The current work suggests that a lack of change in SK2 and GluA1 expression levels in the vHC may play a role in conferring this protection.

Live predator stress in adolescence results in distinct adult behavioral consequences and dorsal diencephalic brain activation patterns

Exposure to traumatic events during childhood increases the risk of adult psychopathology, including anxiety, depression, alcohol use disorders and their co-morbidity. Early life trauma also results in increased symptom complexity, treatment resistance and poor treatment outcomes. The purpose of this study was to establish a novel rodent model of adolescent stress, based on an ethologically relevant life-threatening event, live predator exposure. Rats were exposed to a live predator for 10 min. at three different time points (postnatal day (PND)31, 46 and 61). Adult depression-, anxiety-like behaviors and ethanol consumption were characterized well past the last acute stress event (two weeks). Behavioral profiles across assessments were developed to characterize individual response to adolescent stress. CNS activation patterns in separate groups of subjects were characterized after the early (PND31) and last predator exposure (PND61). Subjects exposed to live-predator adolescent stress generally exhibited less exploratory behavior, less propensity to venture into open spaces, a decreased preference for sweet solutions and decreased ethanol consumption in a two-bottle preference test. Additional studies demonstrated blunted cortisol response and CNS activation patterns suggestive of habenula, rostromedial tegmental (RMTg), dorsal raphe and central amygdala involvement in mediating the adult consequences of adolescent stress. Thus, adolescent stress in the form of live-predator exposure results in significant adult behavioral and neurobiological disturbances. Childhood trauma, its impact on neurodevelopment and the subsequent development of mood disorders is a pervasive theme in mental illness. Improving animal models and our neurobiological understanding of the symptom domains impacted by trauma could significantly improve treatment strategies.

Ketamine metabolite (2R,6R)-hydroxynorketamine reverses behavioral despair produced by adolescent trauma

Early life trauma dramatically increases the risk of developing major depressive disorder (MDD), and is associated with a markedly decreased adult treatment response to antidepressants. Novel treatment approaches are required to treat childhood trauma-associated MDD. Recent studies suggest that the (R,S)-ketamine (ketamine) metabolite, (2R,6R)-hydroxynorketamine (HNK), exerts fast- and long-lasting antidepressant-like effects without ketamine's NMDAR-inhibition-associated adverse side-effect profile. We investigated the therapeutic potential of (2R,6R)-HNK against behavioral despair produced by a novel live-predator stress exposure during adolescence. Male and female C57BL/6J mice were exposed to a live snake or control conditions at post-natal (PND) days 31, 45 and 61. In order to assess the enduring consequences of trauma-exposure, at a minimum of 14 days following the last exposure, mice received inescapable shocks followed by a session with available escape options twenty-four hours later. Mice that manifested enduring escape deficits (helplessness) were treated with vehicle or (2R,6R)-HNK (20 mg/kg, i.p.), 24 h prior to retesting for reversal of escape deficits. We found that a significantly greater number of mice developed the helpless phenotype when they were exposed to the live predator and that the helpless phenotype was reversed in mice treated with (2R,6R)-HNK. There were no sex differences in the response to predator-stress exposure or (2R,6R)-HNK treatment. The live-predator model developed in this study provides an opportunity to further refine our understanding of the neurobiological substrates impacted by adolescent trauma and improve treatment strategies. The demonstrated efficacy of (2R,6R)-HNK in this model suggests a novel therapeutic intervention for a treatment-resistant population.

The impact of trauma characteristics on post-traumatic stress disorder and substance use disorder outcomes across integrated and substance use treatments

Proponents of complex post-traumatic stress disorder (PTSD) constructs suggest that specific trauma characteristics, such as earlier age of first trauma (trauma age) and higher number of traumas (trauma count), may obstruct PTSD symptom reduction in treatment. PTSD and substance use disorders (SUD) commonly co-occur, but the impact of trauma age and count on PTSD treatment responses in a comorbid PTSD and SUD sample is unclear. Further, no studies have examined the impact of trauma characteristics on SUD treatment outcomes or whether their impact on either PTSD or SUD outcomes varies if PTSD is directly addressed. A secondary analysis of a randomized controlled trial was conducted to examine: (1) whether trauma age and count influence comorbid PTSD and SUD (PTSD+SUD) responses during and following treatment; and (2) whether these effects differed across an exposure-based, integrated PTSD+SUD treatment (Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure; COPE) and a SUD-only focused treatment (Relapse Prevention Therapy; RPT). Individuals with PTSD+SUD randomized to COPE (n = 39) or RPT (n = 43) provided weekly measurements of PTSD and SUD. Across COPE and RPT, earlier trauma age predicted reduced SUD improvement (B = -0.01, standard error = 0.00). Trauma count did not predict changes in PTSD or SUD during or following treatment. These findings suggest that excluding individuals from exposure-based, integrated treatments on the basis of trauma characteristics is not empirically supported. However, individuals with earlier trauma ages may require additional or unique clinical attention to improve their SUD outcomes.

Emotion Regulation as a Mediator between Childhood Abuse and Neglect and Posttraumatic Stress Disorder in Women with Substance Use Disorders

A history of childhood abuse and neglect (CAN) is significantly associated with psychopathologies in adulthood, including comorbid posttraumatic stress disorder (PTSD) and substance use disorders (SUD). Difficulties in emotion regulation (ER) might influence the association between CAN and PTSD. The aim of this study was to examine the relationship between CAN and PTSD symptom severity in women with SUD and to investigate the mediating role of general difficulties in ER and its specific dimensions. Method: We examined 320 women, with a current diagnosis of at least subsyndromal PTSD and SUD, using self-report measures of CAN, PTSD symptom severity, and ER difficulties. We conducted both simple and multiple bootstrapping-enhanced mediation analysis to investigate whether general difficulties in ER and its specific dimensions mediate the relationship between CAN and PTSD symptom severity. Results: General difficulties in ER mediated the association between CAN and PTSD symptom severity. CAN significantly predicted adult PTSD symptom severity, directly and indirectly, through ER difficulties. Difficulties engaging in goal directed behavior when distressed was the only ER dimension, which mediated the effect of CAN on PTSD symptoms. Conclusions: Our results suggest that difficulties in ER and specifically difficulties engaging in goal directed behavior when distressed might constitute an influential factor in the relationship between CAN and PTSD symptom severity in a sample of SUD patients, and highlight the importance of targeting ER as a potential treatment focus for patients with comorbid PTSD and SUD.

The possible mediating effect of alcohol dependence on the relationship between adverse childhood experiences and attempted suicide

Adverse childhood experiences (ACEs) and alcohol dependence (AD) carry independent risks for suicidal behavior. While the strength of the association between ACEs and attempted suicide is weakened following adjustment for AD, no study to date has directly been performed to determine whether AD affects the risk of suicide attributable to ACEs. The study aimed to examine the possible role of alcohol dependence (AD) in the relationship between various ACEs and attempted suicide. This cross-sectional study assessed history of ACEs among 184 AD patients and 205 control participants using the Family Health Questionnaire. Lifetime history of attempted suicide was collected using the Chinese version of the Composite International Diagnostic Interview. We used the Sobel test to examine the mediating effects of AD on the relationship between ACEs and attempted suicide. Results showed that the suicide attempters were associated with higher rates of AD and ACEs. The regression analysis showed that AD and multiple ACEs exposure are independently associated with attempted suicide. AD appears as a partial mediator in the relationship between attempted suicide and the specific type of ACE (exposure to a battered mother or sexual abuse) or exposure to ≥3 types of ACEs. We conclude that AD might partially mediate the associations detected between attempted suicide and exposure to a battered mother, sexual abuse, and ≥3 types of ACEs. These observations may provide important insight for intervention strategies aimed at reducing the risk of suicide attempts.

Differential relationships of PTSD and childhood trauma with the course of substance use disorders

A large body of research documents the link between Posttraumatic Stress Disorder (PTSD) and the course of Substance Use Disorders (SUD). Similar relationships have been reported between Childhood Trauma (CT) and the course of illness in patients with SUD even in the absence of PTSD, but few studies have examined differential effects of PTSD and CT (independent of PTSD) in this population. We used the International Diagnostic Checklist (IDCL) and the Posttraumatic Diagnostic Scale (PDS) to diagnose PTSD in a sample of patients with SUD (N = 459). The Childhood Trauma Questionnaire (CTQ) and the European Addiction Severity Index (EuropASI) were administered to assess childhood trauma and addiction related problems including comorbid psychopathological symptoms. The sample was divided into three groups: patients with experiences of CT and PTSD (CT-PTSD), experiences of CT without PTSD (CT-only), and neither experiences of CT nor PTSD (No trauma) to examine their differential associations with the course and severity of SUD. Patients of both the CT-PTSD (n = 95) and the CT-only group (n = 134) reported significantly higher levels of anxiety and depression as well as more suicidal thoughts and suicide attempts during their lifetime than the No trauma group (n = 209). Regarding most variables a graded association became apparent, with the highest level of symptoms in the CT-PTSD group, an intermediate level in the CT-only group and the lowest level in the No trauma group. The CT-PTSD group also differed in almost all substance use variables significantly from the No trauma group, including a younger age at first use of alcohol and cannabis, more cannabis use in the last month, and more lifetime drug overdoses. Our results confirm the relationships of both CT and PTSD with psychiatric symptoms in patients with SUD. Thus, it seems important to include both domains into the routine assessment of SUD patients. Specific treatments for comorbid PTSD but also for other consequences of childhood trauma should be integrated into SUD treatment programs.

Epigenetic mechanisms of alcoholism and stress-related disorders

Stress-related disorders, such as anxiety, early life stress, and posttraumatic stress disorder appear to be important factors in promoting alcoholism, as alcohol consumption can temporarily attenuate the negative affective symptoms of these disorders. Several molecules involved in signaling pathways may contribute to the neuroadaptation induced during alcohol dependence and stress disorders, and among these, brain-derived neurotrophic factor (BDNF), corticotropin releasing factor (CRF), neuropeptide Y (NPY) and opioid peptides (i.e., nociceptin and dynorphin) are involved in the interaction of stress and alcohol. In fact, alterations in the expression and function of these molecules have been associated with the pathophysiology of stress-related disorders and alcoholism. In recent years, various studies have focused on the epigenetic mechanisms that regulate chromatin architecture, thereby modifying gene expression. Interestingly, epigenetic modifications in specific brain regions have been shown to be associated with the neurobiology of psychiatric disorders, including alcoholism and stress. In particular, the enzymes responsible for chromatin remodeling (i.e., histone deacetylases and methyltransferases, DNA methyltransferases) have been identified as common molecular mechanisms for the interaction of stress and alcohol and have become promising therapeutic targets to treat or prevent alcoholism and associated emotional disorders.

Mediating role of childhood emotional abuse on the relationship between severity of ADHD and PTSD symptoms in a sample of male inpatients with alcohol use disorder

The aim of the present study was to evaluate relationship of PTSD symptom severity with severity of ADHD symptoms while controlling the effect of childhood trauma in a sample of male inpatients with alcohol use disorder (AUD). Participants included 190 male inpatients with AUD. Participants were evaluated with the Childhood Trauma Questionnaire (CTQ-28), the Adult ADHD Self-Report Scale (ASRS) and PTSD Checklist Civilian version (PCL-C). PTSD and ADHD scores were mildly correlated with severity of childhood trauma and types of traumas, the only exception was emotional neglect, which was not correlated with PTSD and ADHD. Severity of ADHD symptoms was associated with the severity of PTSD symptoms, together with the severity of childhood trauma in a linear regression model. In another linear regression model where dimensions of ADHD and childhood trauma were considered as independent variables, emotional abuse and both inattentive and hyperactive/impulsive dimensions of ADHD were associated with the severity of PTSD. These findings suggest that the severity of adult ADHD symptoms is related with the severity of PTSD symptoms, while severity of childhood trauma, particularly emotional abuse may have an mediating role on this relationship among male inpatients with AUD.

Discrepancies between clinical needs and helpseeking behaviors in co-occurring posttraumatic stress and alcohol use disorders

OBJECTIVE

The aim of the study was to compare subjects dually diagnosed with posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) to those with only one or none of these conditions regarding helpseeking needs and behaviors.

METHOD

Data from a large community sample (N=3694) were used to assess the associations among lifetime PTSD and AUD, other psychiatric disorders, clinical characteristics and lifetime helpseeking behaviors derived from a semi-structured interview.

RESULTS

Comorbid individuals had more severe clinical profiles and were more impaired than individuals with either PTSD or AUD alone or those with no/other psychiatric conditions. However, they did not differ in overall helpseeking behavior from any other group. Those with comorbid PTSD/AUD were even less likely than the other groups to seek help for depression and anxiety disorders through specific treatment facilities or the use of prescribed psychotropic drugs.

CONCLUSIONS

Despite a greater need for treatment the comorbid group did not seek more help than the others. Their lower use of prescribed drugs supports the self-medication hypothesis, suggesting that those individuals relieve their symptoms through higher alcohol use instead. Our findings underline the need for health care facilities to encourage helpseeking behavior in the aftermath of stressful life events.