1 248 123 ADVANCE IN STRESS FOR DEPRESSIVE DISORDER. STRESS IS AN ADAPTIVE RESPONSE TO ENVIRONMENT AVERSIVE STIMULI AND A COMMON LIFE EXPERIENCE OF ONE'S DAILY LIFE. CHRONIC OR EXCESSIVE STRESS ESPECIALLY THAT HAPPENED IN EARLY LIFE IS FOUND TO BE DELETERIOUS TO INDIVIDUAL'S PHYSICAL AND MENTAL HEALTH, WHICH IS HIGHLY RELATED TO DEPRESSIVE DISORDERS ONSET. STRESSFUL LIFE EVENTS ARE CONSISTENTLY CONSIDERED TO BE THE HIGH-RISK FACTORS OF ENVIRONMENT FOR PREDISPOSING DEPRESSIVE DISORDERS. IN LINKING STRESSFUL LIFE EVENTS WITH DEPRESSIVE DISORDER ONSET, DYSREGULATED HPA AXIS ACTIVITY IS SUPPOSED TO PLAY AN IMPORTANT ROLE IN MEDIATING AVERSIVE IMPACTS OF LIFE STRESS ON BRAIN STRUCTURE AND FUNCTION. INCREASING EVIDENCE HAVE INDICATED THE STRONG ASSOCIATION OF STRESS, ESPECIALLY THE CHRONIC STRESS AND EARLY LIFE STRESS, WITH DEPRESSIVE DISORDERS DEVELOPMENT, WHILE THE ASSOCIATION OF STRESS WITH DEPRESSION IS MODERATED BY GENETIC RISK FACTORS, INCLUDING POLYMORPHISM OF SERT, BDNF, GR, FKBP5, MR, AND CRHR1. MEANWHILE, STRESSFUL LIFE EXPERIENCE PARTICULARLY EARLY LIFE STRESS WILL EXERT EPIGENETIC MODIFICATION IN THESE RISK GENES VIA DNA METHYLATION AND MIRNA REGULATION TO GENERATE LONG-LASTING EFFECTS ON THESE GENES EXPRESSION, WHICH IN TURN CAUSE BRAIN STRUCTURAL AND FUNCTIONAL ALTERATION, AND FINALLY INCREASE THE VULNERABILITY TO DEPRESSIVE DISORDERS. THEREFORE, THE INTERACTION OF ENVIRONMENT WITH GENE, IN WHICH STRESSFUL LIFE EXPOSURE INTERPLAY WITH GENETIC RISK FACTORS AND EPIGENETIC MODIFICATION, IS ESSENTIAL IN PREDICTING DEPRESSIVE DISORDERS DEVELOPMENT. AS THE MEDIATOR OF ENVIRONMENTAL RISK FACTORS, STRESS WILL FUNCTION TOGETHER WITH GENETIC AND EPIGENETIC MECHANISM TO INFLUENCE BRAIN STRUCTURE AND FUNCTION, PHYSIOLOGY AND PSYCHOLOGY, AND FINALLY THE VULNERABILITY TO DEPRESSIVE DISORDERS. 2019 2 6228 37 THE LINKS BETWEEN STRESS AND DEPRESSION: PSYCHONEUROENDOCRINOLOGICAL, GENETIC, AND ENVIRONMENTAL INTERACTIONS. THE ROLE OF STRESS IN THE ORIGIN AND DEVELOPMENT OF DEPRESSION MAY BE CONCEIVED AS THE RESULT OF MULTIPLE CONVERGING FACTORS, INCLUDING THE CHRONIC EFFECT OF ENVIRONMENTAL STRESSORS AND THE LONG-LASTING EFFECTS OF STRESSFUL EXPERIENCES DURING CHILDHOOD, ALL OF WHICH MAY INDUCE PERSISTENT HYPERACTIVITY OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. THESE CHANGES, INCLUDING INCREASED AVAILABILITY OF CORTICOTROPIN-RELEASING FACTOR AND CORTISOL, ARE ALSO ASSOCIATED WITH HYPERACTIVITY OF THE AMYGDALA, HYPOACTIVITY OF THE HIPPOCAMPUS, AND DECREASED SEROTONERGIC NEUROTRANSMISSION, WHICH TOGETHER RESULT IN INCREASED VULNERABILITY TO STRESS. THE ROLE OF OTHER MONOAMINERGIC NEUROTRANSMITTERS, GENETIC POLYMORPHISMS, EPIGENETIC MECHANISMS, INFLAMMATORY PROCESSES, AND ALTERED COGNITIVE PROCESSING HAS ALSO BEEN CONSIDERED IN THE DEVELOPMENT OF A COMPREHENSIVE MODEL OF THE INTERACTIONS BETWEEN DIFFERENT FACTORS OF VULNERABILITY. FURTHER UNDERSTANDING OF THE UNDERLYING MECHANISMS THAT LINK THESE FACTORS MAY CONTRIBUTE SIGNIFICANTLY TO THE DEVELOPMENT OF MORE EFFECTIVE TREATMENTS AND PREVENTIVE STRATEGIES IN THE INTERFACE BETWEEN STRESS AND MOOD DISORDERS. 2016 3 2269 48 EPIGENETIC PROGRAMMING OF THE NEUROENDOCRINE STRESS RESPONSE BY ADULT LIFE STRESS. THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS IS CRITICALLY INVOLVED IN THE NEUROENDOCRINE REGULATION OF STRESS ADAPTATION, AND THE RESTORATION OF HOMEOSTASIS FOLLOWING STRESS EXPOSURE. DYSREGULATION OF THIS AXIS IS ASSOCIATED WITH STRESS-RELATED PATHOLOGIES LIKE MAJOR DEPRESSIVE DISORDER, POST-TRAUMATIC STRESS DISORDER, PANIC DISORDER AND CHRONIC ANXIETY. IT HAS LONG BEEN UNDERSTOOD THAT STRESS DURING EARLY LIFE CAN HAVE A SIGNIFICANT LASTING INFLUENCE ON THE DEVELOPMENT OF THE NEUROENDOCRINE SYSTEM AND ITS NEURAL REGULATORS, PARTIALLY BY MODIFYING EPIGENETIC REGULATION OF GENE EXPRESSION, WITH IMPLICATIONS FOR HEALTH AND WELL-BEING IN LATER LIFE. EVIDENCE IS ACCUMULATING THAT EPIGENETIC PLASTICITY ALSO EXTENDS TO ADULTHOOD, PROPOSING IT AS A MECHANISM BY WHICH PSYCHOLOGICAL TRAUMA LATER IN LIFE CAN LONG-LASTINGLY AFFECT HPA AXIS FUNCTION, BRAIN PLASTICITY, NEURONAL FUNCTION AND BEHAVIOURAL ADAPTATION TO NEUROPSYCHOLOGICAL STRESS. FURTHER CORROBORATING THIS CLAIM IS THE PHENOMENON THAT THESE EPIGENETIC CHANGES CORRELATE WITH THE BEHAVIOURAL CONSEQUENCES OF TRAUMA EXPOSURE. THEREBY, EPIGENETIC MODIFICATIONS PROVIDE A PUTATIVE MOLECULAR MECHANISM BY WHICH THE BEHAVIOURAL PHENOTYPE AND TRANSCRIPTIONAL/TRANSLATIONAL POTENTIAL OF GENES INVOLVED IN HPA AXIS REGULATION CAN CHANGE DRASTICALLY IN RESPONSE TO ENVIRONMENTAL CHALLENGES, AND APPEAR AN IMPORTANT TARGET FOR TREATMENT OF STRESS-RELATED DISORDERS. HOWEVER, IMPROVED INSIGHT IS REQUIRED TO INCREASE THEIR THERAPEUTIC (DRUG) POTENTIAL. HERE, WE PROVIDE AN OVERVIEW OF THE GROWING BODY OF LITERATURE DESCRIBING THE EPIGENETIC MODULATION OF THE (PRIMARILY NEUROENDOCRINE) STRESS RESPONSE AS A CONSEQUENCE OF ADULT LIFE STRESS AND INTERPRET THE IMPLICATIONS FOR, AND THE CHALLENGES INVOLVED IN APPLYING THIS KNOWLEDGE TO, THE IDENTIFICATION AND TREATMENT OF STRESS-RELATED PSYCHIATRIC DISORDERS. 2017 4 5164 42 PRECLINICAL AND CLINICAL EVIDENCE OF DNA METHYLATION CHANGES IN RESPONSE TO TRAUMA AND CHRONIC STRESS. EXPOSURE TO CHRONIC STRESS, EITHER REPEATED SEVERE ACUTE OR MODERATE SUSTAINED STRESS, IS ONE OF THE STRONGEST RISK FACTORS FOR THE DEVELOPMENT OF PSYCHOPATHOLOGIES SUCH AS POST-TRAUMATIC STRESS DISORDER AND DEPRESSION. CHRONIC STRESS IS LINKED WITH SEVERAL LASTING BIOLOGICAL CONSEQUENCES, PARTICULARLY TO THE STRESS ENDOCRINE SYSTEM BUT ALSO AFFECTING INTERMEDIATE PHENOTYPES SUCH AS BRAIN STRUCTURE AND FUNCTION, IMMUNE FUNCTION, AND BEHAVIOR. ALTHOUGH GENETIC PREDISPOSITION CONFERS A PROPORTION OF THE RISK, THE MOST RELEVANT MOLECULAR MECHANISMS DETERMINING THOSE SUSCEPTIBLE AND RESILIENT TO THE EFFECTS OF STRESS AND TRAUMA MAY BE EPIGENETIC. EPIGENETICS REFERS TO THE MECHANISMS THAT REGULATE GENOMIC INFORMATION BY DYNAMICALLY CHANGING THE PATTERNS OF TRANSCRIPTION AND TRANSLATION OF GENES. MOUNTING EVIDENCE FROM PRECLINICAL RODENT AND CLINICAL POPULATION STUDIES STRONGLY SUPPORT THAT EPIGENETIC MODIFICATIONS CAN OCCUR IN RESPONSE TO TRAUMATIC AND CHRONIC STRESS. HERE, WE DISCUSS THIS LITERATURE EXAMINING STRESS-INDUCED EPIGENETIC CHANGES IN PRECLINICAL MODELS AND CLINICAL COHORTS OF STRESS AND TRAUMA OCCURRING EARLY IN LIFE OR IN ADULTHOOD. WE HIGHLIGHT THAT A COMPLEX RELATIONSHIP BETWEEN THE TIMING OF ENVIRONMENTAL STRESSORS AND GENETIC PREDISPOSITIONS LIKELY MEDIATE THE RESPONSE TO CHRONIC STRESS OVER TIME, AND THAT A BETTER UNDERSTANDING OF EPIGENETIC CHANGES IS NEEDED BY FURTHER INVESTIGATIONS IN LONGITUDINAL AND POSTMORTEM BRAIN CLINICAL COHORTS. 2017 5 291 35 AGING AND STRESS: PAST HYPOTHESES, PRESENT APPROACHES AND PERSPECTIVES. BRAIN AGING HAS BEEN SUGGESTED TO BE CONDITIONED BY AN EXCESSIVE GLUCOCORTIOID SECRETION LEADING TO DAMAGES ON BRAIN AREAS INVOLVED NOT ONLY IN COGNITIVE AND EMOTIONAL PROCESSES BUT ALSO IN THE CONTROL OF THE ACTIVITY OF THE HYPOTHALAMIC-PITUITARY ADRENAL AXIS. THIS REVIEW DESCRIBES SOME OF THE HYPOTHESIS THAT TRY TO EXPLAIN THE RELATION BETWEEN THE DYSREGULATION OF THE STRESS RESPONSE AND BRAIN AGING, FOCUSING ON CORTICOSTERONE BUT ALSO ON NEUROTRANSMISSION IN THE HIPPOCAMPUS, THE PREFRONTAL CORTEX AND THE AMYGDALA. MOREOVER, DIFFERENT MOLECULAR FACTORS CAN ACCOUNT FOR AN ENHANCED VULNERABILITY OF THE AGED BRAIN TO STRESS EXPOSURE, SPECIALLY FOR RESILIENCE. AMONG THEM, GOOD CANDIDATES COULD BE THOSE MECHANISMS DETERMINING THE LEVELS OF CORTICOSTERONE IN THE BRAIN, SEVERAL MOLECULES DOWNSTREAM GLUCOCORTICOID RECEPTOR ACTIVATION (IE: HEAT SHOCK PROTEINS, BAG-1) OR EVEN THE EPIGENETIC PROGRAMMING OF THE HPA AXIS IN EARLY STAGES. IN CONCLUSION, GENETIC AND ENVIRONMENTAL FACTORS (EARLY LIFE STRESS, CHRONIC STRESS DURING ADULTHOOD) CAN PRODUCE AN ENHANCED VULNERABILITY AND A REDUCED RESILIENCE OF THE BRAIN TO SUBSEQUENT STRESS EXPOSURES OR TO METABOLIC CHALLENGES LEADING, IN TURN, TO AN UNSUCCESSFUL AGING OF THE BRAIN. HOWEVER, RESULTS OBTAINED WITH THE USE OF THE ENVIRONMENTAL ENRICHMENT MODEL IN ANIMALS, ADDED TO SEVERAL RESULTS IN HUMANS ALSO DESCRIBED IN THIS REVIEW SUGGEST THAT POSITIVE ENVIRONMENTAL FACTORS (COGNITIVE-DEMANDING TASKS OR PHYSICAL EXERCISE) CAN HELP TO MAINTAIN NEURONAL PLASTICITY DURING AGING AND TO PROTECT THE BRAIN AGAINST THE DAMAGING EFFECTS OF STRESS EXPOSURE. 2011 6 4622 30 NEUROBIOLOGICAL DEVELOPMENT IN THE CONTEXT OF CHILDHOOD TRAUMA. NEUROBIOLOGICAL SYSTEMS MAY BE PARTICULARLY SUSCEPTIBLE TO DELETERIOUS IMPACT OF CHILDHOOD TRAUMA, AND THE IMPACT OF CHILDHOOD TRAUMA ON DEVELOPMENT AND SUBSEQUENT FUNCTIONAL OUTCOMES ACROSS THE LIFESPAN HAS BEEN WELL-DOCUMENTED. THE CURRENT REVIEW ADDRESSES THE NEUROBIOLOGICAL IMPACT OF EXPOSURE TO INTERPERSONAL TRAUMA IN CHILDHOOD IN THE CONTEXT OF EXECUTIVE FUNCTION, EMOTION REGULATION, AND DISSOCIATION/INTEROCEPTIVE AWARENESS. SUBSEQUENT RISK FOR PTSD AND DEPRESSION IS ALSO DISCUSSED. THE PATHWAY OF RISK FROM CHILDHOOD TRAUMA TO THESE COGNITIVE, EMOTIONAL, AND PSYCHIATRIC OUTCOMES IS ADDRESSED IN TERMS OF POTENTIAL STRUCTURAL AND FUNCTIONAL ALTERATIONS WITHIN THE HIPPOCAMPUS, PREFRONTAL CORTEX, AND AMYGDALA RESULTING FROM CHRONIC OR REPEATED ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND ITS INTERACTION WITH AND INFLUENCE ON GENETIC AND EPIGENETIC PROCESSES DURING SENSITIVE PERIODS OF DEVELOPMENT. IMPLICATIONS FOR PRACTICE ARE DISCUSSED. 2017 7 2159 31 EPIGENETIC MECHANISMS IMPACTED BY CHRONIC STRESS ACROSS THE RODENT LIFESPAN. EXPOSURES TO STRESS AT ALL STAGES OF DEVELOPMENT CAN LEAD TO LONG-TERM BEHAVIOURAL EFFECTS, IN PART THROUGH CHANGES IN THE EPIGENOME. THIS REVIEW DESCRIBES RODENT RESEARCH SUGGESTING THAT STRESS IN PRENATAL, POSTNATAL, ADOLESCENT AND ADULT STAGES LEADS TO LONG-TERM CHANGES IN EPIGENETIC REGULATION IN THE BRAIN WHICH HAVE CAUSAL IMPACTS ON RODENT BEHAVIOUR. WE FOCUS ON STRESS-INDUCED EPIGENETIC CHANGES THAT HAVE BEEN LINKED TO BEHAVIOURAL DEFICITS INCLUDING POOR LEARNING AND MEMORY, AND INCREASED ANXIETY-LIKE AND DEPRESSIVE-LIKE BEHAVIOURS. INTERESTINGLY, ASPECTS OF THESE STRESS-INDUCED BEHAVIOURAL CHANGES CAN BE TRANSMITTED TO OFFSPRING ACROSS SEVERAL GENERATIONS, A PHENOMENON THAT HAS BEEN PROPOSED TO RESULT VIA EPIGENETIC MECHANISMS IN THE GERMLINE. HERE, WE ALSO DISCUSS EVIDENCE FOR THE DIFFERENTIAL IMPACT OF STRESS ON THE EPIGENOME IN MALES AND FEMALES, CONSCIOUS OF THE FACT THAT THE MAJORITY OF PUBLISHED STUDIES HAVE ONLY INVESTIGATED MALES. THIS HAS LED TO A LIMITED PICTURE OF THE EPIGENETIC IMPACT OF STRESS, HIGHLIGHTING THE NEED FOR FUTURE STUDIES TO INVESTIGATE FEMALES AS WELL AS MALES. 2022 8 6729 39 VULNERABILITY TO STROKE: IMPLICATIONS OF PERINATAL PROGRAMMING OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS. CHRONIC STRESS IS CAPABLE OF EXACERBATING EACH MAJOR, MODIFIABLE, ENDOGENOUS RISK FACTOR FOR CEREBROVASCULAR AND CARDIOVASCULAR DISEASE. INDEED, EXPOSURE TO STRESS CAN INCREASE BOTH THE INCIDENCE AND SEVERITY OF STROKE, PRESUMABLY THROUGH ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. NOW THAT CHARACTERIZATION OF THE MECHANISMS UNDERLYING EPIGENETIC PROGRAMMING OF THE HPA AXIS IS WELL UNDERWAY, THERE HAS BEEN RENEWED INTEREST IN EXAMINING THE ROLE OF EARLY ENVIRONMENT ON THE EVOLUTION OF HEALTH CONDITIONS ACROSS THE ENTIRE LIFESPAN. INDEED, NEONATAL MANIPULATIONS IN RODENTS THAT REDUCE STRESS RESPONSIVITY, AND SUBSEQUENT LIFE-TIME EXPOSURE TO GLUCOCORTICOIDS, ARE ASSOCIATED WITH A REDUCTION IN THE DEVELOPMENT OF NEUROENDOCRINE, NEUROANATOMICAL, AND COGNITIVE DYSFUNCTIONS THAT TYPICALLY PROGRESS WITH AGE. ALTHOUGH IMPROVED DAY TO DAY REGULATION OF THE HPA AXIS ALSO MAY BE ACCOMPANIED BY A DECREASE IN STROKE RISK, EVIDENCE FROM RODENT STUDIES SUGGEST THAT AN ASSOCIATED COST COULD BE INCREASED SUSCEPTIBILITY TO INFLAMMATION AND NEURONAL DEATH IN THE EVENT THAT A STROKE DOES OCCUR AND THE INDIVIDUAL IS EXPOSED TO PERSISTENTLY ELEVATED CORTICOSTEROIDS. GIVEN ITS IMPORTANCE IN REGULATION OF HEALTH AND DISEASE STATES, ANY LONG-TERM MODULATION OF THE HPA AXIS IS LIKELY TO BE ASSOCIATED WITH BOTH BENEFITS AND POTENTIAL RISKS. THE GOALS OF THIS REVIEW ARTICLE ARE TO EXAMINE (1) THE CLINICAL AND EXPERIMENTAL DATA SUGGESTING THAT NEONATAL EXPERIENCES CAN SHAPE HPA AXIS REGULATION, (2) THE INFLUENCE OF STRESS AND THE HPA AXIS ON STROKE INCIDENCE AND SEVERITY, AND (3) THE POTENTIAL FOR NEONATAL PROGRAMMING OF THE HPA AXIS TO IMPACT ADULT CEREBROVASCULAR HEALTH. 2009 9 6184 40 THE IMPACT OF ENVIRONMENTAL FACTORS IN SEVERE PSYCHIATRIC DISORDERS. DURING THE LAST DECADES, SCHIZOPHRENIA HAS BEEN REGARDED AS A DEVELOPMENTAL DISORDER. THE NEURODEVELOPMENTAL HYPOTHESIS PROPOSES SCHIZOPHRENIA TO BE RELATED TO GENETIC AND ENVIRONMENTAL FACTORS LEADING TO ABNORMAL BRAIN DEVELOPMENT DURING THE PRE- OR POSTNATAL PERIOD. FIRST DISEASE SYMPTOMS APPEAR IN EARLY ADULTHOOD DURING THE SYNAPTIC PRUNING AND MYELINATION PROCESS. META-ANALYSES OF STRUCTURAL MRI STUDIES REVEALING HIPPOCAMPAL VOLUME DEFICITS IN FIRST-EPISODE PATIENTS AND IN THE LONGITUDINAL DISEASE COURSE CONFIRM THIS HYPOTHESIS. APART FROM THE INFLUENCE OF RISK GENES IN SEVERE PSYCHIATRIC DISORDERS, ENVIRONMENTAL FACTORS MAY ALSO IMPACT BRAIN DEVELOPMENT DURING THE PERINATAL PERIOD. SEVERAL ENVIRONMENTAL FACTORS SUCH AS ANTENATAL MATERNAL VIRUS INFECTIONS, OBSTETRIC COMPLICATIONS ENTAILING HYPOXIA AS COMMON FACTOR OR STRESS DURING NEURODEVELOPMENT HAVE BEEN IDENTIFIED TO PLAY A ROLE IN SCHIZOPHRENIA AND BIPOLAR DISORDER, POSSIBLY CONTRIBUTING TO SMALLER HIPPOCAMPAL VOLUMES. IN MAJOR DEPRESSION, PSYCHOSOCIAL STRESS DURING THE PERINATAL PERIOD OR IN ADULTHOOD IS AN IMPORTANT TRIGGER. IN ANIMAL STUDIES, CHRONIC STRESS OR REPEATED ADMINISTRATION OF GLUCOCORTICOIDS HAVE BEEN SHOWN TO INDUCE DEGENERATION OF GLUCOCORTICOID-SENSITIVE HIPPOCAMPAL NEURONS AND MAY CONTRIBUTE TO THE PATHOPHYSIOLOGY OF AFFECTIVE DISORDERS. EPIGENETIC MECHANISMS ALTERING THE CHROMATIN STRUCTURE SUCH AS HISTONE ACETYLATION AND DNA METHYLATION MAY MEDIATE EFFECTS OF ENVIRONMENTAL FACTORS TO TRANSCRIPTIONAL REGULATION OF SPECIFIC GENES AND BE A PROMINENT FACTOR IN GENE-ENVIRONMENTAL INTERACTION. IN ANIMAL MODELS, GENE-ENVIRONMENTAL INTERACTION SHOULD BE INVESTIGATED MORE INTENSELY TO UNRAVEL PATHOPHYSIOLOGICAL MECHANISMS. THESE FINDINGS MAY LEAD TO NEW THERAPEUTIC STRATEGIES INFLUENCING EPIGENETIC TARGETS IN SEVERE PSYCHIATRIC DISORDERS. 2014 10 5316 35 PSYCHOLOGICAL STRESS IN EARLY LIFE AS A PREDISPOSING FACTOR FOR THE DEVELOPMENT OF CHRONIC PAIN: CLINICAL AND PRECLINICAL EVIDENCE AND NEUROBIOLOGICAL MECHANISMS. A WEALTH OF RESEARCH OVER THE PAST 2 DECADES HAS EXPANDED OUR UNDERSTANDING OF THE IMPACT OF EARLY-LIFE ADVERSITY ON PHYSIOLOGICAL FUNCTION AND, CONSEQUENTLY, HEALTH AND WELLBEING IN LATER LIFE. EARLY-LIFE ADVERSITY INCREASES THE RISK OF DEVELOPING A NUMBER OF DISORDERS, SUCH AS CHRONIC PAIN, FIBROMYALGIA, AND IRRITABLE BOWEL SYNDROME. ALTHOUGH MUCH OF THE RESEARCH HAS EXAMINED THE IMPACT OF PHYSICAL MALTREATMENT, AN INCREASING NUMBER OF STUDIES HAVE BEEN PUBLISHED OVER THE PAST FEW YEARS EXAMINING THE EFFECT OF CHILDHOOD PSYCHOLOGICAL STRESS AND TRAUMA ON THE DEVELOPMENT OF VARIOUS TYPES OF CHRONIC PAIN CONDITIONS. WE REVIEW THE CLINICAL AND PRECLINICAL DATA EXAMINING THE LINK AMONG EARLY-LIFE PSYCHOLOGICAL STRESS, ALTERED NOCICEPTIVE BEHAVIOR, AND CHRONIC PAIN IN LATER LIFE. EVIDENCE SUPPORTING A ROLE FOR CERTAIN KEY NEUROBIOLOGICAL SUBSTRATES, INCLUDING THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS; MONOAMINERGIC, OPIOIDERGIC, ENDOCANNABINOID AND IMMUNE SYSTEMS; AND EPIGENETIC MECHANISMS IN THE ASSOCIATION BETWEEN EARLY-LIFE PSYCHOLOGICAL STRESS AND CHRONIC PAIN, IS PROVIDED. GREATER UNDERSTANDING OF THE IMPACT OF EARLY-LIFE STRESS MAY INFORM THE DEVELOPMENT OF PERSONALIZED TREATMENTS FOR CHRONIC PAIN IN LATER LIFE AND STRATEGIES TO PREVENT ITS ONSET IN SUSCEPTIBLE INDIVIDUALS. (C) 2016 WILEY PERIODICALS, INC. 2017 11 235 32 ADDING FUEL TO THE FIRE: THE IMPACT OF STRESS ON THE AGEING BRAIN. BOTH AGEING AND CHRONIC STRESS ARE ASSOCIATED WITH ALTERED BRAIN PLASTICITY, DYSREGULATION OF THE IMMUNE SYSTEM, AND AN INCREASED RISK OF DEVELOPING BRAIN DISORDERS; ALL OF WHICH HAVE CONSEQUENCES FOR COGNITIVE AND EMOTIONAL PROCESSING. HERE WE EXAMINE THE SIMILARITIES BETWEEN BEHAVIOURAL CHANGES DURING AGEING AND STRESS ALTERED BEHAVIOURS (ANXIETY, DEPRESSIVE-LIKE BEHAVIOUR, COGNITION, AND SOCIABILITY) IN RODENTS AND HUMANS. THE MOLECULAR MECHANISMS HYPOTHESISED TO MEDIATE AGE-RELATED CHANGES IN BRAIN FUNCTION INCLUDING DYSFUNCTION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS, DYSREGULATION OF NEUROTRANSMISSION AND NEUROTROPHIC FACTOR SIGNALLING, INCREASED INFLAMMATORY STATE, GENETIC AND EPIGENETIC CHANGES, OXIDATIVE STRESS, METABOLIC CHANGES, AND CHANGES IN THE MICROBIOTA-GUT-BRAIN AXIS ARE DISCUSSED. FINALLY, WE EXPLORE HOW THE ALREADY STRESSED AGED BRAIN PSYCHOLOGICALLY AND PHYSIOLOGICALLY RESPONDS TO EXTERNAL STRESSORS. 2015 12 2021 40 EPIGENETIC CHANGES ASSOCIATED WITH DIFFERENT TYPES OF STRESSORS AND SUICIDE. STRESS IS ASSOCIATED WITH VARIOUS EPIGENETIC CHANGES. SOME STRESS-INDUCED EPIGENETIC CHANGES ARE HIGHLY DYNAMIC, WHEREAS OTHERS ARE ASSOCIATED WITH LASTING MARKS ON THE EPIGENOME. IN OUR STUDY, A COMPREHENSIVE NARRATIVE REVIEW OF THE LITERATURE WAS PERFORMED BY INVESTIGATING THE EPIGENETIC CHANGES THAT OCCUR WITH ACUTE STRESS, CHRONIC STRESS, EARLY CHILDHOOD STRESS, AND TRAUMATIC STRESS EXPOSURES, ALONG WITH EXAMINING THOSE OBSERVED IN POST-MORTEM BRAINS OR BLOOD SAMPLES OF SUICIDE COMPLETERS AND ATTEMPTERS. IN ADDITION, THE TRANSGENERATIONAL EFFECTS OF THESE CHANGES ARE REPORTED. FOR ALL TYPES OF STRESS STUDIES EXAMINED, THE GENES NR3C1, OXTR, SLC6A4, AND BDNF REPRODUCIBLY SHOWED EPIGENETIC CHANGES, WITH SOME MODIFICATIONS OBSERVED TO BE PASSED DOWN TO SUBSEQUENT GENERATIONS FOLLOWING STRESS EXPOSURES. THE AFOREMENTIONED GENES ARE KNOWN TO BE INVOLVED IN NEURONAL DEVELOPMENT AND HORMONAL REGULATION AND ARE ALL ASSOCIATED WITH SUSCEPTIBILITY TO MENTAL HEALTH DISORDERS INCLUDING DEPRESSION, ANXIETY, PERSONALITY DISORDERS, AND PTSD (POST-TRAUMATIC STRESS DISORDER). FURTHER RESEARCH IS WARRANTED IN ORDER TO DETERMINE THE SCOPE OF EPIGENETIC ACTIONABLE TARGETS IN INDIVIDUALS SUFFERING FROM THE LONG-LASTING EFFECTS OF STRESSFUL EXPERIENCES. 2023 13 632 49 BIOLOGICAL CORRELATES OF EARLY LIFE STRESSFUL EVENTS IN MAJOR DEPRESSIVE DISORDER. MAJOR DEPRESSIVE DISORDER (MDD) IS THE MOST COMMON PSYCHIATRIC DISORDER AND RESPONDS FOR IMPORTANT PSYCHOSOCIAL CONSEQUENCES. STRESSFUL LIFE EVENTS, ESPECIALLY EARLY LIFE STRESS (ELS), CONTRIBUTE TO AN INCREASED PROBABILITY TO DEVELOP MDD, LEADING IN PARTICULAR TO SEVERE AND CHRONIC MANIFESTATION AND UNFAVORABLE TREATMENT OUTCOME. THE ASSOCIATION BETWEEN ELS AND MDD SEEMS TO HAVE BIOLOGICAL BASES, CONSISTING IN DYSREGULATIONS OCCURRING AT DIFFERENT LEVELS. THE AIM OF THIS NARRATIVE REVIEW IS TO PROPOSE AN OVERVIEW OF THE LITERATURE RANGING FROM GENETIC, EPIGENETIC, EXPRESSION AND PROTEIN TO NEUROIMAGING CORRELATES UNDERLYING THIS RELATIONSHIP. A SEARCH ON PUBMED OF STUDIES ASSESSING BIOLOGICAL CORRELATES OF ELS IN MDD DEVELOPMENT, FOCUSING ON HUMAN STUDIES CONDUCTED IN BOTH PERIPHERAL AND BRAIN TISSUES, WAS PERFORMED. EVIDENCE INDICATED THAT THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND THE SEROTONERGIC, DOPAMINERGIC, NEUROTROPHIN AND OXYTOCIN SYSTEMS MIGHT PLAY A ROLE IN THE MEDIATION BETWEEN ELS AND MDD. THE MOST CONSISTENT RESULTS WERE FOUND FOR GENETIC AND EPIGENETIC STUDIES AND INDICATED A JOINT INVOLVEMENT OF THE SYSTEMS MENTIONED. EXPRESSION STUDIES ARE LESS NUMEROUS AND POINT TO AN INVOLVEMENT OF STRESS-RELATED SYSTEMS. CONCERNING PROTEIN STUDIES, THE MAIN MEDIATORS ARE MARKERS RELATED TO THE INFLAMMATORY AND IMMUNE SYSTEMS. NEUROIMAGING STUDIES AIMING AT EVALUATING BRAIN ALTERATIONS CONNECTING ELS AND MDD IN RELATION TO BIOMARKERS INDICATED THE HIPPOCAMPUS, THE AMYGDALA AND THE FRONTAL CORTEX AS IMPORTANT ANATOMICAL MEDIATORS. THESE FINDINGS CAN BUILD THE BASES FOR FUTURE RESEARCH AND CLINICAL INTERVENTIONS; INDEED, THE CLARIFICATION OF BIOLOGICAL MECHANISMS MEDIATING THE RELATIONSHIP BETWEEN ELS AND MDD CAN LEAD TO NEW AND INDIVIDUALIZED PREVENTIVE AND THERAPEUTIC POSSIBILITIES. 2021 14 682 42 BRAIN ON STRESS: HOW THE SOCIAL ENVIRONMENT GETS UNDER THE SKIN. STRESS IS A STATE OF THE MIND, INVOLVING BOTH BRAIN AND BODY AS WELL AS THEIR INTERACTIONS; IT DIFFERS AMONG INDIVIDUALS AND REFLECTS NOT ONLY MAJOR LIFE EVENTS BUT ALSO THE CONFLICTS AND PRESSURES OF DAILY LIFE THAT ALTER PHYSIOLOGICAL SYSTEMS TO PRODUCE A CHRONIC STRESS BURDEN THAT, IN TURN, IS A FACTOR IN THE EXPRESSION OF DISEASE. THIS BURDEN REFLECTS THE IMPACT OF NOT ONLY LIFE EXPERIENCES BUT ALSO GENETIC VARIATIONS AND INDIVIDUAL HEALTH BEHAVIORS SUCH AS DIET, PHYSICAL ACTIVITY, SLEEP, AND SUBSTANCE ABUSE; IT ALSO REFLECTS STABLE EPIGENETIC MODIFICATIONS IN DEVELOPMENT THAT SET LIFELONG PATTERNS OF PHYSIOLOGICAL REACTIVITY AND BEHAVIOR THROUGH BIOLOGICAL EMBEDDING OF EARLY ENVIRONMENTS INTERACTING WITH CUMULATIVE CHANGE FROM EXPERIENCES OVER THE LIFESPAN. HORMONES ASSOCIATED WITH THE CHRONIC STRESS BURDEN PROTECT THE BODY IN THE SHORT RUN AND PROMOTE ADAPTATION (ALLOSTASIS), BUT IN THE LONG RUN, THE BURDEN OF CHRONIC STRESS CAUSES CHANGES IN THE BRAIN AND BODY THAT CAN LEAD TO DISEASE (ALLOSTATIC LOAD AND OVERLOAD). BRAIN CIRCUITS ARE PLASTIC AND REMODELED BY STRESS TO CHANGE THE BALANCE BETWEEN ANXIETY, MOOD CONTROL, MEMORY, AND DECISION MAKING. SUCH CHANGES MAY HAVE ADAPTIVE VALUE IN PARTICULAR CONTEXTS, BUT THEIR PERSISTENCE AND LACK OF REVERSIBILITY CAN BE MALADAPTIVE. HOWEVER, THE CAPACITY OF BRAIN PLASTICITY TO EFFECTS OF STRESSFUL EXPERIENCES IN ADULT LIFE HAS ONLY BEGUN TO BE EXPLORED ALONG WITH THE EFFICACY OF TOP-DOWN STRATEGIES FOR HELPING THE BRAIN CHANGE ITSELF, SOMETIMES AIDED BY PHARMACEUTICAL AGENTS AND OTHER TREATMENTS. 2012 15 3313 35 HIPPOCAMPAL BDNF IN PHYSIOLOGICAL CONDITIONS AND SOCIAL ISOLATION. EXPOSURE OF AN ORGANISM TO CHRONIC PSYCHOSOCIAL STRESS MAY AFFECT BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF) EXPRESSION THAT HAS BEEN IMPLICATED IN THE ETIOLOGY OF PSYCHIATRIC DISORDERS, SUCH AS DEPRESSION. GIVEN THAT DEPRESSION IN HUMANS HAS BEEN LINKED WITH SOCIAL STRESS, THE CHRONIC SOCIAL STRESS PARADIGMS FOR MODELING PSYCHIATRIC DISORDERS IN ANIMALS HAVE THUS BEEN DEVELOPED. CHRONIC SOCIAL ISOLATION IN ANIMAL MODELS GENERALLY CAUSES CHANGES IN HYPOTHALAMIC-PITUITARY-ADRENAL AXIS FUNCTIONING, ASSOCIATED WITH ANXIETY- AND DEPRESSIVE-LIKE BEHAVIORS. ALSO, THIS CHRONIC STRESS CAUSES DOWNREGULATION OF BDNF PROTEIN AND MRNA IN THE HIPPOCAMPUS, A STRESS-SENSITIVE BRAIN REGION CLOSELY RELATED TO THE PATHOPHYSIOLOGY OF DEPRESSION. IN THIS REVIEW, WE DISCUSS THE CURRENT KNOWLEDGE REGARDING THE STRUCTURE, FUNCTION, INTRACELLULAR SIGNALING, INTER-INDIVIDUAL DIFFERENCES AND EPIGENETIC REGULATION OF BDNF IN BOTH PHYSIOLOGICAL CONDITIONS AND DEPRESSION AND CHANGES IN CORTICOSTERONE LEVELS, AS A MARKER OF STRESS RESPONSE. SINCE BDNF LEVELS ARE AGE DEPENDENT IN HUMANS AND RODENTS, THIS REVIEW WILL ALSO HIGHLIGHT THE EFFECTS OF ADOLESCENT AND ADULT CHRONIC SOCIAL ISOLATION MODELS OF BOTH GENDERS ON THE BDNF EXPRESSION. 2017 16 1754 38 EARLY LIFE STRESS, THE DEVELOPMENT OF AGGRESSION AND NEUROENDOCRINE AND NEUROBIOLOGICAL CORRELATES: WHAT CAN WE LEARN FROM ANIMAL MODELS? EARLY LIFE STRESS (CHILD AND ADOLESCENT ABUSE, NEGLECT AND TRAUMA) INDUCES ROBUST ALTERATIONS IN EMOTIONAL AND SOCIAL FUNCTIONING RESULTING IN ENHANCED RISK FOR THE DEVELOPMENT OF PSYCHOPATHOLOGIES SUCH AS MOOD AND AGGRESSIVE DISORDERS. HERE, AN OVERVIEW IS GIVEN ON RECENT FINDINGS IN PRIMATE AND RODENT MODELS OF EARLY LIFE STRESS, DEMONSTRATING THAT CHRONIC DEPRIVATION OF EARLY MATERNAL CARE AS WELL AS CHRONIC DEPRIVATION OF EARLY PHYSICAL INTERACTIONS WITH PEERS ARE PROFOUND RISK FACTORS FOR THE DEVELOPMENT OF INAPPROPRIATE AGGRESSIVE BEHAVIORS. ALTERATIONS IN THE HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL (HPA), VASOPRESSIN AND SEROTONIN SYSTEMS AND THEIR RELEVANCE FOR THE REGULATION OF AGGRESSION ARE DISCUSSED. DATA SUGGEST THAT SOCIAL DEPRIVATION-INDUCED INAPPROPRIATE FORMS OF AGGRESSION ARE ASSOCIATED WITH HIGH OR LOW HPA AXIS (RE)ACTIVITY AND A GENERALLY LOWER FUNCTIONING OF THE SEROTONIN SYSTEM IN ADULTHOOD. MOREOVER, GENETIC AND EPIGENETIC MODIFICATIONS IN HPA AND SEROTONIN SYSTEMS INFLUENCE THE OUTCOME OF EARLY LIFE STRESS AND MAY EVEN MODERATE ADVERSE EFFECTS OF EARLY SOCIAL DEPRIVATION ON AGGRESSION. A MORE COMPREHENSIVE STUDY OF AGGRESSION, NEUROENDOCRINE, NEUROBIOLOGICAL AND (EPI)GENETIC CORRELATES OF EARLY LIFE STRESS USING ANIMAL MODELS IS NECESSARY TO PROVIDE A BETTER UNDERSTANDING OF THE INVASIVE AGGRESSIVE DEFICITS OBSERVED IN HUMANS EXPOSED TO CHILD MALTREATMENT. 2009 17 2011 46 EPIGENETIC BASIS OF MENTAL ILLNESS. PSYCHIATRIC DISORDERS ARE COMPLEX MULTIFACTORIAL ILLNESSES INVOLVING CHRONIC ALTERATIONS IN NEURAL CIRCUIT STRUCTURE AND FUNCTION AS WELL AS LIKELY ABNORMALITIES IN GLIAL CELLS. WHILE GENETIC FACTORS ARE IMPORTANT IN THE ETIOLOGY OF MOST MENTAL DISORDERS, THE RELATIVELY HIGH RATES OF DISCORDANCE AMONG IDENTICAL TWINS, PARTICULARLY FOR DEPRESSION AND OTHER STRESS-RELATED SYNDROMES, CLEARLY INDICATE THE IMPORTANCE OF ADDITIONAL MECHANISMS. ENVIRONMENTAL FACTORS SUCH AS STRESS ARE KNOWN TO PLAY A ROLE IN THE ONSET OF THESE ILLNESSES. EXPOSURE TO SUCH ENVIRONMENTAL INSULTS INDUCES STABLE CHANGES IN GENE EXPRESSION, NEURAL CIRCUIT FUNCTION, AND ULTIMATELY BEHAVIOR, AND THESE MALADAPTATIONS APPEAR DISTINCT BETWEEN DEVELOPMENTAL VERSUS ADULT EXPOSURES. INCREASING EVIDENCE INDICATES THAT THESE SUSTAINED ABNORMALITIES ARE MAINTAINED BY EPIGENETIC MODIFICATIONS IN SPECIFIC BRAIN REGIONS. INDEED, TRANSCRIPTIONAL DYSREGULATION AND THE ABERRANT EPIGENETIC REGULATION THAT UNDERLIES THIS DYSREGULATION IS A UNIFYING THEME IN PSYCHIATRIC DISORDERS. HERE, WE PROVIDE A PROGRESS REPORT OF EPIGENETIC STUDIES OF THE THREE MAJOR PSYCHIATRIC SYNDROMES, DEPRESSION, SCHIZOPHRENIA, AND BIPOLAR DISORDER. WE REVIEW THE LITERATURE DERIVED FROM ANIMAL MODELS OF THESE DISORDERS AS WELL AS FROM STUDIES OF POSTMORTEM BRAIN TISSUE FROM HUMAN PATIENTS. WHILE EPIGENETIC STUDIES OF MENTAL ILLNESS REMAIN AT EARLY STAGES, UNDERSTANDING HOW ENVIRONMENTAL FACTORS RECRUIT THE EPIGENETIC MACHINERY WITHIN SPECIFIC BRAIN REGIONS TO CAUSE LASTING CHANGES IN DISEASE SUSCEPTIBILITY AND PATHOPHYSIOLOGY IS REVEALING NEW INSIGHT INTO THE ETIOLOGY AND TREATMENT OF THESE CONDITIONS. 2016 18 3001 39 GENETIC, EPIGENETIC AND ENVIRONMENTAL IMPACT ON SEX DIFFERENCES IN SOCIAL BEHAVIOR. THE FIELD OF BEHAVIORAL NEUROENDOCRINOLOGY HAS GENERATED THOUSANDS OF STUDIES THAT INDICATE DIFFERENCES IN BRAIN STRUCTURE AND REACTIVITY TO GONADAL STEROIDS THAT PRODUCE SEX-SPECIFIC PATTERNS OF SOCIAL BEHAVIOR. HOWEVER, RAPIDLY EMERGING EVIDENCE SHOWS THAT GENETIC POLYMORPHISMS AND RESULTING DIFFERENCES IN THE EXPRESSION OF NEUROACTIVE PEPTIDES AND RECEPTORS AS WELL AS EARLY-LIFE EXPERIENCE AND EPIGENETIC CHANGES ARE IMPORTANT MODIFIERS OF SOCIAL BEHAVIOR. FURTHERMORE, DUE TO ITS INHERENT COMPLEXITY, THE NEUROCHEMICAL MECHANISMS UNDERLYING SEX DIFFERENCES IN SOCIAL BEHAVIOR ARE USUALLY STUDIED IN A TIGHTLY REGULATED LABORATORY SETTING RATHER THAN IN COMPLEX ENVIRONMENTS. IMPORTANTLY, SPECIFIC HORMONES MAY ELICIT A RANGE OF DIFFERENT BEHAVIORS DEPENDING ON THE CUES PRESENT IN THESE ENVIRONMENTS. FOR EXAMPLE, INDIVIDUALS EXPOSED TO A PSYCHOSOCIAL STRESSOR MAY RESPOND DIFFERENTLY TO THE EFFECTS OF A GONADAL STEROID THAN THOSE NOT EXPOSED TO CHRONIC STRESS. THE OBJECTIVE OF THIS REVIEW IS NOT TO RE-EXAMINE THE ACTIVATIONAL EFFECTS OF HORMONES ON SEX DIFFERENCES IN SOCIAL BEHAVIOR BUT RATHER TO CONSIDER HOW GENETIC AND ENVIRONMENTAL FACTORS MODIFY THE EFFECTS OF HORMONES ON BEHAVIOR. WE WILL FOCUS ON ESTROGEN AND ITS RECEPTORS BUT CONSIDERATION IS ALSO GIVEN TO THE ROLE OF ANDROGENS. FURTHERMORE, WE HAVE LIMITED OUR DISCUSSIONS TO THE IMPORTANCE OF OXYTOCIN AND VASOPRESSIN AS TARGETS OF GONADAL STEROIDS AND HOW THESE EFFECTS ARE MODIFIED BY GENETIC AND EXPERIENTIAL SITUATIONS. TAKEN TOGETHER, THE DATA CLEARLY UNDERSCORE THE NEED TO EXPAND RESEARCH INITIATIVES TO CONSIDER GENE-ENVIRONMENT INTERACTIONS FOR BETTER UNDERSTANDING OF THE NEUROBIOLOGY OF SEX DIFFERENCES IN SOCIAL BEHAVIOR. 2009 19 2386 34 EPIGENETIC REGULATORY MECHANISMS IN STRESS-INDUCED BEHAVIOR. STRESS RESPONSE IS CONSIDERED TO HAVE ADAPTIVE VALUE FOR ORGANISMS FACED WITH STRESSFUL CONDITION. CHRONIC STRESS HOWEVER ADVERSELY AFFECTS THE PHYSIOLOGY AND MAY LEAD TO NEUROPSYCHIATRIC DISORDERS. REPEATED STRESSFUL EVENTS IN ANIMAL MODELS HAVE BEEN SHOWN TO CAUSE LONG-LASTING CHANGES IN NEURAL CIRCUITRIES AT MOLECULAR, CELLULAR, AND PHYSIOLOGICAL LEVEL, LEADING TO DISORDERS OF MOOD AS WELL AS COGNITION. MOLECULAR STUDIES IN RECENT YEARS HAVE IMPLICATED DIVERSE EPIGENETIC MECHANISMS, INCLUDING HISTONE MODIFICATIONS, DNA METHYLATION, AND NONCODING RNAS, THAT UNDERLIE DYSREGULATION OF GENES IN THE AFFECTED NEURAL CIRCUITRIES IN CHRONIC STRESS-INDUCED PATHOPHYSIOLOGY. A REVIEW OF THE MYRIAD EPIGENETIC REGULATORY MECHANISMS ASSOCIATED WITH NEURAL AND BEHAVIORAL RESPONSES IN ANIMAL MODELS OF STRESS-INDUCED NEUROPSYCHIATRIC DISORDERS IS PRESENTED HERE. THE REVIEW ALSO DEALS WITH CLINICAL EVIDENCE OF THE EPIGENETIC DYSREGULATION OF GENES IN PSYCHIATRIC DISORDERS WHERE CHRONIC STRESS APPEARS TO UNDERLIE THE ETIOPATHOLOGY. 2014 20 2949 37 GENETIC AND EPIGENETIC CONSEQUENCE OF EARLY-LIFE SOCIAL STRESS ON DEPRESSION: ROLE OF SEROTONIN-ASSOCIATED GENES. EARLY-LIFE ADVERSITY CAUSED BY POOR SOCIAL BONDING AND DEPRIVED MATERNAL CARE IS KNOWN TO AFFECT MENTAL WELLBEING AND PHYSICAL HEALTH. IT IS A FORM OF CHRONIC SOCIAL STRESS THAT PERSISTS BECAUSE OF A NEGATIVE ENVIRONMENT, AND THE CONSEQUENCES ARE LONG-LASTING ON MENTAL HEALTH. THE PRESENCE OF SOCIAL STRESS DURING EARLY LIFE CAN HAVE AN EPIGENETIC EFFECT ON THE BODY, POSSIBLY RESULTING IN MANY COMPLEX MENTAL DISORDERS, INCLUDING DEPRESSION IN LATER LIFE. HERE, WE REVIEW THE EVIDENCE FOR EARLY-LIFE SOCIAL STRESS-INDUCED EPIGENETIC CHANGES THAT MODULATE JUVENILE AND ADULT SOCIAL BEHAVIOR (DEPRESSION AND ANXIETY). THIS REVIEW HAS A PARTICULAR EMPHASIS ON THE INTERACTION BETWEEN EARLY-LIFE SOCIAL STRESS AND GENETIC VARIATION OF SEROTONIN ASSOCIATE GENES INCLUDING THE SEROTONIN TRANSPORTER GENE (5-HTT; ALSO KNOWN AS SLC6A4), WHICH ARE KEY MOLECULES INVOLVED IN DEPRESSION. 2020