1 47 153 A CONCEPTUAL MODEL OF BIOPSYCHOSOCIAL MECHANISMS OF TRANSITION FROM ACUTE TO CHRONIC POSTSURGICAL PAIN IN CHILDREN AND ADOLESCENTS. ACUTE AND CHRONIC PAIN ARE HIGHLY PREVALENT AND IMPACTFUL CONSEQUENCES OF SURGERY ACROSS THE LIFESPAN, YET A COMPREHENSIVE CONCEPTUAL MODEL ENCOMPASSING BIOPSYCHOSOCIAL FACTORS UNDERLYING ACUTE TO CHRONIC PAIN TRANSITION IS LACKING, PARTICULARLY IN YOUTH. BUILDING ON PRIOR CHRONIC POSTSURGICAL PAIN MODELS, WE PROPOSE A NEW CONCEPTUAL MODEL OF BIOPSYCHOSOCIAL MECHANISMS OF TRANSITION FROM ACUTE TO CHRONIC POSTSURGICAL PAIN. THIS REVIEW AIMS TO SUMMARIZE EXISTING RESEARCH EXAMINING KEY FACTORS UNDERLYING ACUTE TO CHRONIC POSTSURGICAL PAIN TRANSITION IN ORDER TO GUIDE PREVENTION AND INTERVENTION EFFORTS AIMED AT ADDRESSING THIS HEALTH ISSUE IN CHILDREN. AS PAIN TRANSITIONS FROM ACUTE NOCICEPTIVE PAIN TO CHRONIC PAIN, CHANGES IN THE PERIPHERAL AND CENTRAL NERVOUS SYSTEM CONTRIBUTE TO THE CHRONIFICATION OF PAIN AFTER SURGERY. THESE CHANGES INCLUDE ALTERATIONS IN SENSORY PAIN PROCESSING AND PSYCHOSOCIAL PROCESSES (PSYCHOLOGICAL, BEHAVIORAL, AND SOCIAL COMPONENTS), WHICH PROMOTE THE DEVELOPMENT OF CHRONIC PAIN. PATIENT-RELATED PREMORBID FACTORS (EG, DEMOGRAPHIC FACTORS, GENETIC PROFILE, AND MEDICAL FACTORS SUCH AS PREMORBID PAIN) MAY FURTHER MODULATE THESE CHANGES. FACTORS RELATED TO ACUTE INJURY AND RECOVERY (EG, SURGICAL AND TREATMENT FACTORS), AS WELL AS BIOLOGICAL RESPONSE TO SURGERY (EG, EPIGENETIC, INFLAMMATORY, AND ENDOCRINE FACTORS), MAY ALSO INFLUENCE THIS PROCESS. OVERALL, LONGITUDINAL STUDIES EXAMINING TEMPORAL PATHWAYS OF BIOPSYCHOSOCIAL PROCESSES INCLUDING BOTH RISK AND RESILIENCY FACTORS WILL BE ESSENTIAL TO IDENTIFY THE MECHANISMS INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN. RESEARCH IS ALSO NEEDED TO UNRAVEL CONNECTIONS BETWEEN THE ACUTE PAIN EXPERIENCE, OPIOID EXPOSURE, AND SENSORY PAIN PROCESSING DURING ACUTE TO CHRONIC PAIN TRANSITION. FURTHERMORE, FUTURE STUDIES SHOULD INCLUDE LARGER AND MORE DIVERSE SAMPLES TO MORE FULLY EXPLORE RISK FACTORS IN A BROADER RANGE OF PEDIATRIC SURGERIES. THE USE OF CONCEPTUAL MODELS TO GUIDE INTERVENTION APPROACHES TARGETING MECHANISMS OF TRANSITION FROM ACUTE TO CHRONIC PAIN WILL SIGNIFICANTLY ADVANCE THIS FIELD AND IMPROVE OUTCOMES FOR CHILDREN AND ADOLESCENTS UNDERGOING SURGERY. 2020 2 4591 38 NARRATIVE REVIEW OF THE COMPLEX INTERACTION BETWEEN PAIN AND TRAUMA IN CHILDREN: A FOCUS ON BIOLOGICAL MEMORY, PRECLINICAL DATA, AND EPIGENETIC PROCESSES. THE INCIDENCE AND COLLECTIVE IMPACT OF EARLY ADVERSE EXPERIENCES, TRAUMA, AND PAIN CONTINUE TO INCREASE. THIS UNDERSCORES THE URGENT NEED FOR TRANSLATIONAL EFFORTS BETWEEN CLINICAL AND PRECLINICAL RESEARCH TO BETTER UNDERSTAND THE UNDERLYING MECHANISMS AND DEVELOP EFFECTIVE THERAPEUTIC APPROACHES. AS OUR UNDERSTANDING OF THESE ISSUES IMPROVES FROM STUDIES IN CHILDREN AND ADOLESCENTS, WE CAN CREATE MORE PRECISE PRECLINICAL MODELS AND ULTIMATELY TRANSLATE OUR FINDINGS BACK TO CLINICAL PRACTICE. A MULTIDISCIPLINARY APPROACH IS ESSENTIAL FOR ADDRESSING THE COMPLEX AND WIDE-RANGING EFFECTS OF THESE EXPERIENCES ON INDIVIDUALS AND SOCIETY. THIS NARRATIVE REVIEW AIMS TO (1) DEFINE PAIN AND TRAUMA EXPERIENCES IN CHILDHOOD AND ADOLESCENTS, (2) DISCUSS THE RELATIONSHIP BETWEEN PAIN AND TRAUMA, (3) CONSIDER THE ROLE OF BIOLOGICAL MEMORY, (4) DECIPHER THE RELATIONSHIP BETWEEN PAIN AND TRAUMA USING PRECLINICAL DATA, AND (5) EXAMINE THE ROLE OF THE ENVIRONMENT BY INTRODUCING THE IMPORTANCE OF EPIGENETIC PROCESSES. THE ULTIMATE SCOPE IS TO BETTER UNDERSTAND THE WIDE-RANGING EFFECTS OF TRAUMA, ABUSE, AND CHRONIC PAIN ON CHILDREN AND ADOLESCENTS, HOW THEY OCCUR, AND HOW TO PREVENT OR MITIGATE THEIR EFFECTS AND DEVELOP EFFECTIVE TREATMENT STRATEGIES THAT ADDRESS BOTH THE UNDERLYING CAUSES AND THE ASSOCIATED PHYSIOLOGICAL AND PSYCHOLOGICAL EFFECTS. 2023 3 1248 46 CURRENT EVIDENCE FOR BIOLOGICAL BIOMARKERS AND MECHANISMS UNDERLYING ACUTE TO CHRONIC PAIN TRANSITION ACROSS THE PEDIATRIC AGE SPECTRUM. CHRONIC PAIN IS HIGHLY PREVALENT IN THE PEDIATRIC POPULATION. MANY FACTORS ARE INVOLVED IN THE TRANSITION FROM ACUTE TO CHRONIC PAIN. CURRENTLY, THERE ARE CONCEPTUAL MODELS PROPOSED, BUT THEY LACK A MECHANISTICALLY SOUND INTEGRATED THEORY CONSIDERING THE STAGES OF CHILD DEVELOPMENT. OBJECTIVE BIOMARKERS ARE CRITICALLY NEEDED FOR THE DIAGNOSIS, RISK STRATIFICATION, AND PROGNOSIS OF THE PATHOLOGICAL STAGES OF PAIN CHRONIFICATION. IN THIS ARTICLE, WE SUMMARIZE THE CURRENT EVIDENCE ON MECHANISMS AND BIOMARKERS OF ACUTE TO CHRONIC PAIN TRANSITIONS IN INFANTS AND CHILDREN THROUGH THE DEVELOPMENTAL LENS. THE GOAL IS TO IDENTIFY GAPS AND OUTLINE FUTURE DIRECTIONS FOR BASIC AND CLINICAL RESEARCH TOWARD A DEVELOPMENTALLY INFORMED THEORY OF PAIN CHRONIFICATION IN THE PEDIATRIC POPULATION. AT THE OUTSET, THE IMPORTANCE OF OBJECTIVE BIOMARKERS FOR CHRONIFICATION OF PAIN IN CHILDREN IS OUTLINED, FOLLOWED BY A SUMMARY OF THE CURRENT EVIDENCE ON THE MECHANISMS OF ACUTE TO CHRONIC PAIN TRANSITION IN ADULTS, IN ORDER TO CONTRAST WITH THE DEVELOPMENTAL MECHANISMS OF PAIN CHRONIFICATION IN THE PEDIATRIC POPULATION. EVIDENCE IS PRESENTED TO SHOW THAT CHRONIC PAIN MAY HAVE ITS ORIGIN FROM INSULTS EARLY IN LIFE, WHICH PRIME THE CHILD FOR THE DEVELOPMENT OF CHRONIC PAIN IN LATER LIFE. FURTHERMORE, AVAILABLE GENETIC, EPIGENETIC, PSYCHOPHYSICAL, ELECTROPHYSIOLOGICAL, NEUROIMAGING, NEUROIMMUNE, AND SEX MECHANISMS ARE DESCRIBED IN INFANTS AND OLDER CHILDREN. IN CONCLUSION, FUTURE DIRECTIONS ARE DISCUSSED WITH A FOCUS ON RESEARCH GAPS, TRANSLATIONAL AND CLINICAL IMPLICATIONS. UTILIZATION OF DEVELOPMENTAL MECHANISMS FRAMEWORK TO INFORM CLINICAL DECISION-MAKING AND STRATEGIES FOR PREVENTION AND MANAGEMENT OF ACUTE TO CHRONIC PAIN TRANSITIONS IN CHILDREN, IS HIGHLIGHTED. 2023 4 4914 34 PAIN VULNERABILITY: A NEUROBIOLOGICAL PERSPECTIVE. THERE ARE MANY KNOWN RISK FACTORS FOR CHRONIC PAIN CONDITIONS, YET THE BIOLOGICAL UNDERPINNINGS THAT LINK THESE FACTORS TO ABNORMAL PROCESSING OF PAINFUL SIGNALS ARE ONLY JUST BEGINNING TO BE EXPLORED. THIS REVIEW WILL DISCUSS THE POTENTIAL MECHANISMS THAT HAVE BEEN PROPOSED TO UNDERLIE VULNERABILITY AND RESILIENCE TOWARD DEVELOPING CHRONIC PAIN. PARTICULAR FOCUS WILL BE GIVEN TO GENETIC AND EPIGENETIC PROCESSES, PRIMING EFFECTS ON A CELLULAR LEVEL, AND ALTERATIONS IN BRAIN NETWORKS CONCERNED WITH REWARD, MOTIVATION/LEARNING AND DESCENDING MODULATORY CONTROL. ALTHOUGH RESEARCH IN THIS AREA IS STILL IN ITS INFANCY, A BETTER UNDERSTANDING OF HOW PAIN VULNERABILITY EMERGES HAS THE POTENTIAL TO HELP IDENTIFY INDIVIDUALS AT RISK AND MAY OPEN UP NEW THERAPEUTIC AVENUES. 2014 5 6260 28 THE MOLECULAR NEUROBIOLOGY OF CHRONIC PAIN-INDUCED DEPRESSION. THE INCREASING NUMBER OF INDIVIDUALS WITH COMORBIDITIES POSES AN URGENT NEED TO IMPROVE THE MANAGEMENT OF PATIENTS WITH MULTIPLE CO-EXISTING DISEASES. AMONG THESE COMORBIDITIES, CHRONIC PAIN AND MOOD DISORDERS, TWO LONG-LASTING DISABLING CONDITIONS THAT SIGNIFICANTLY REDUCE THE QUALITY OF LIFE, COULD BE CITED FIRST. THE RECENT DEVELOPMENT OF ANIMAL MODELS ACCELERATED THE STUDIES FOCUSING ON THE UNDERLYING MECHANISMS OF THE CHRONIC PAIN AND DEPRESSION/ANXIETY COMORBIDITY. THIS REVIEW PROVIDES AN OVERVIEW OF CLINICAL AND PRE-CLINICAL STUDIES PERFORMED OVER THE PAST TWO DECADES ADDRESSING THE MOLECULAR ASPECTS OF THE COMORBID RELATIONSHIP OF CHRONIC PAIN AND DEPRESSION. WE THUS FOCUSED ON THE STUDIES THAT INVESTIGATED THE MOLECULAR CHARACTERISTICS OF THE COMORBID RELATIONSHIP BETWEEN CHRONIC PAIN AND MOOD DISORDERS, ESPECIALLY MAJOR DEPRESSIVE DISORDERS, FROM THE GENETIC AND EPIGENETIC POINT OF VIEW TO KEY NEUROMODULATORS WHICH HAVE BEEN SHOWN TO PLAY AN IMPORTANT ROLE IN THIS COMORBIDITY. 2019 6 1229 40 CRITICAL WINDOWS: EXPLORING THE ASSOCIATION BETWEEN PERINATAL TRAUMA, EPIGENETICS, AND CHRONIC PAIN. CHRONIC PAIN IS HIGHLY PREVALENT AND BURDENSOME, AFFECTING MILLIONS OF PEOPLE WORLDWIDE. ALTHOUGH IT EMERGES AT ANY POINT IN LIFE, IT OFTEN MANIFESTS IN ADOLESCENCE. GIVEN THAT ADOLESCENCE IS A UNIQUE DEVELOPMENTAL PERIOD, ADDITIONAL STRAINS ASSOCIATED WITH PERSISTENT AND OFTEN IDIOPATHIC PAIN LEAD TO SIGNIFICANT LONG-TERM CONSEQUENCES. WHILE THERE IS NO SINGULAR CAUSE FOR THE CHRONIFICATION OF PAIN, EPIGENETIC MODIFICATIONS THAT LEAD TO NEURAL REORGANIZATION MAY UNDERPIN CENTRAL SENSITIZATION AND SUBSEQUENT MANIFESTATION OF PAIN HYPERSENSITIVITY. EPIGENETIC PROCESSES ARE PARTICULARLY ACTIVE DURING THE PRENATAL AND EARLY POSTNATAL YEARS. WE DEMONSTRATE HOW EXPOSURE TO VARIOUS TRAUMAS, SUCH AS INTIMATE PARTNER VIOLENCE WHILE IN UTERO OR ADVERSE CHILDHOOD EXPERIENCES, CAN SIGNIFICANTLY INFLUENCE EPIGENETIC REGULATION WITHIN THE BRAIN AND IN TURN MODIFY PAIN-RELATED PROCESSES. WE PROVIDE COMPELLING EVIDENCE THAT THE BURDEN OF CHRONIC PAIN IS LIKELY INITIATED EARLY IN LIFE, OFTEN BEING TRANSMITTED FROM MOTHER TO OFFSPRING. WE ALSO HIGHLIGHT TWO PROMISING PROPHYLACTIC STRATEGIES, OXYTOCIN ADMINISTRATION AND PROBIOTIC USE, THAT HAVE THE POTENTIAL TO ATTENUATE THE EPIGENETIC CONSEQUENCES OF EARLY ADVERSITY. OVERALL, WE ADVANCE UNDERSTANDING OF THE CAUSAL RELATIONSHIP BETWEEN TRAUMA AND ADOLESCENT CHRONIC PAIN BY HIGHLIGHTING EPIGENETIC MECHANISMS THAT UNDERLIE THIS TRANSMISSION OF RISK, ULTIMATELY INFORMING HOW TO PREVENT THIS RISING EPIDEMIC. 2023 7 5164 41 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 8 2963 27 GENETIC AND EPIGENETIC MECHANISMS LINKING PAIN AND PSYCHIATRIC DISORDERS. THE NEUROPHYSIOLOGICAL LINK BETWEEN NEUROPATHIC PAIN AND DEPRESSION REMAINS UNKNOWN DESPITE EVIDENT HIGH COMORBIDITY OF THESE TWO DISORDERS. HOWEVER, THERE IS CONVINCING EVIDENCE THAT GENOTYPE PLAYS A ROLE IN BOTH PAIN AND DEPRESSION. USING VARIOUS TYPES OF GENETIC ANALYSIS - POPULATION GENETICS, CYTOGENETICS AND MOLECULAR TECHNOLOGIES - SPECIFIC GENES HAVE BEEN IMPLICATED IN MEDIATING ALMOST ALL ASPECTS OF NOCICEPTION AND MOOD DISORDERS. THE CURRENT REVIEW ATTEMPTS TO IDENTIFY SPECIFIC GENES AND EPIGENETIC MECHANISMS COMMON TO BOTH DISORDERS. IT IS CONCLUDED THAT EXTERNAL AND INTERNAL FACTORS (INFLAMMATION, STRESS, GENDER, ETC.) THAT CONTRIBUTE TO THE PATHOLOGIES MAY DO SO THROUGH EPIGENETIC MECHANISMS THAT MAY AFFECT EXPRESSION OF THESE PARTICULAR GENES. THE POSSIBLE INVOLVEMENT OF EPIGENETIC REGULATION IN PAIN AND PSYCHIATRIC DISORDERS SUGGESTS THAT TREATMENTS TARGETING EPIGENETIC MECHANISMS THAT MEDIATE ADVERSE LIFE EVENTS SHOULD BE CONSIDERED. 2015 9 2611 38 EPIGENETICS: A PROMISING PARADIGM FOR BETTER UNDERSTANDING AND MANAGING PAIN. EPIGENETIC REGULATION OF GENE EXPRESSION IS A RAPIDLY GROWING AREA OF RESEARCH. CONSIDERING THE LONGEVITY AND PLASTICITY OF NEURONS, THE STUDIES ON EPIGENETIC PATHWAYS IN THE NERVOUS SYSTEM SHOULD BE OF SPECIAL INTEREST FOR BOTH EPIGENETICISTS AND NEUROSCIENTISTS. ACTIVATION OR INACTIVATION OF DIFFERENT EPIGENETIC PATHWAYS BECOMES MORE PRONOUNCED WHEN THE CELLS EXPERIENCE RAPID CHANGES IN THEIR ENVIRONMENT, AND SUCH CHANGES CAN BE EASILY CAUSED BY INJURY AND INFLAMMATION, RESULTING IN PAIN PERCEPTION OR DISTORTION OF PAIN PERCEPTION (EG, HYPERALGESIA). THEREFORE, IN THIS REGARD, THE FIELD OF PAIN IS AT AN ADVANTAGE TO STUDY THE EPIGENETIC PATHWAYS. MORE IMPORTANTLY, UNDERSTANDING PAIN FROM AN EPIGENETICS POINT OF VIEW WOULD PROVIDE A NEW PARADIGM FOR DEVELOPING DRUGS OR STRATEGIES FOR PAIN MANAGEMENT. IN THIS REVIEW, WE INTRODUCE BASIC CONCEPTS OF EPIGENETICS, INCLUDING CHROMATIN DYNAMICS, HISTONE MODIFICATIONS, DNA METHYLATION, AND RNA-INDUCED GENE SILENCING. IN ADDITION, WE PROVIDE EVIDENCE FROM PUBLISHED STUDIES SUGGESTING WIDE IMPLICATION OF DIFFERENT EPIGENETIC PATHWAYS WITHIN PAIN PATHWAYS. PERSPECTIVE: THIS ARTICLE PROVIDES A BRIEF OVERVIEW OF EPIGENETIC PATHWAYS FOR GENE REGULATION AND HIGHLIGHTS THEIR INVOLVEMENT IN PAIN. OUR GOAL IS TO EXPOSE THE READERS TO THESE CONCEPTS SO THAT PAIN-RELATED PHENOTYPES CAN BE INVESTIGATED FROM THE EPIGENETIC POINT OF VIEW. 2013 10 6739 39 WHEN ENVIRONMENT MEETS GENETICS: A CLINICAL REVIEW OF THE EPIGENETICS OF PAIN, PSYCHOLOGICAL FACTORS, AND PHYSICAL ACTIVITY. EPIGENETIC MECHANISMS REPRESENT A LINK BETWEEN THE ENVIRONMENT AND GENE FUNCTION. RECENT RESEARCH SHOWS HOW EARLY LIFE STRESS, INFLAMMATION, AND PHYSICAL ACTIVITY CAN INFLUENCE GENE EXPRESSION THROUGH EPIGENETIC MECHANISMS. EPIGENETIC CHANGES-SUCH AS DNA METHYLATION AND MICRORNA INTERFERENCE-CAN BE MEASURED IN HUMANS AND MIGHT SOON BECOME IMPORTANT BIOLOGICAL MARKERS. EPIGENETIC MARKS CAN ACCOMPANY CLINICAL ASSESSMENT TO MEASURE THE EFFECTIVENESS OF VARIOUS INTERVENTIONS, SUCH AS EXERCISE THERAPY. IN ADDITION, EPIGENETICS IS IMPROVING THE UNDERSTANDING OF IMPORTANT UNDERLYING MECHANISMS RELATED TO THE CENTRAL NERVOUS SYSTEM, THE OPIOIDERGIC SYSTEM, AND STRESS RESPONSES. EPIGENETICS IS CLOSING A GAP IN OUR EXPLANATORY ABILITIES AND SHOULD BE IMPLEMENTED TO BROADEN THE FIELD OF REHABILITATION SCIENCES, PROMOTE A MECHANISM-BASED CLINICAL REASONING, AND DEVELOP NEW TREATMENTS. IN THE PRESENT REVIEW, WE FOCUSED ON EPIGENETIC MECHANISMS RELATED TO PAIN, PSYCHOLOGICAL FACTORS (SUCH AS FEAR AND ANXIETY), AND PHYSICAL ACTIVITY, TRANSLATING RELEVANT FINDINGS FROM THESE 3 DIFFERENT, YET RELATED, AREAS OF CARDINAL IMPORTANCE FOR CLINICIANS. 2019 11 6211 30 THE INTERPLAY BETWEEN OXIDATIVE STRESS, EXERCISE, AND PAIN IN HEALTH AND DISEASE: POTENTIAL ROLE OF AUTONOMIC REGULATION AND EPIGENETIC MECHANISMS. OXIDATIVE STRESS CAN BE INDUCED BY VARIOUS STIMULI AND ALTERED IN CERTAIN CONDITIONS, INCLUDING EXERCISE AND PAIN. ALTHOUGH MANY STUDIES HAVE INVESTIGATED OXIDATIVE STRESS IN RELATION TO EITHER EXERCISE OR PAIN, THE LITERATURE PRESENTS CONFLICTING RESULTS. THEREFORE, THIS REVIEW CRITICALLY DISCUSSES EXISTING LITERATURE ABOUT THIS TOPIC, AIMING TO PROVIDE A CLEAR OVERVIEW OF KNOWN INTERACTIONS BETWEEN OXIDATIVE STRESS, EXERCISE, AND PAIN IN HEALTHY PEOPLE AS WELL AS IN PEOPLE WITH CHRONIC PAIN, AND TO HIGHLIGHT POSSIBLE CONFOUNDING FACTORS TO KEEP IN MIND WHEN REFLECTING ON THESE INTERACTIONS. IN ADDITION, AUTONOMIC REGULATION AND EPIGENETIC MECHANISMS ARE PROPOSED AS POTENTIAL MECHANISMS OF ACTION UNDERLYING THE INTERPLAY BETWEEN OXIDATIVE STRESS, EXERCISE, AND PAIN. THIS REVIEW HIGHLIGHTS THAT THE RELATION BETWEEN OXIDATIVE STRESS, EXERCISE, AND PAIN IS POORLY UNDERSTOOD AND NOT STRAIGHTFORWARD, AS IT IS DEPENDENT ON THE CHARACTERISTICS OF EXERCISE, BUT ALSO ON WHICH POPULATION IS INVESTIGATED. TO BE ABLE TO COMPARE STUDIES ON THIS TOPIC, STRICT GUIDELINES SHOULD BE DEVELOPED TO LIMIT THE EFFECT OF SEVERAL CONFOUNDING FACTORS. THIS WAY, THE TRUE INTERPLAY BETWEEN OXIDATIVE STRESS, EXERCISE, AND PAIN, AND THE UNDERLYING MECHANISMS OF ACTION CAN BE REVEALED AND VALIDATED VIA INDEPENDENT STUDIES. 2020 12 5316 33 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 13 6458 38 TIME COURSE OF DNA METHYLATION IN PAIN CONDITIONS: FROM EXPERIMENTAL MODELS TO HUMANS. BACKGROUND AND OBJECTIVE: THROUGHOUT THE LAST DECADE, RESEARCH HAS UNCOVERED ASSOCIATIONS BETWEEN PAIN AND EPIGENETIC ALTERATIONS CAUSED BY ENVIRONMENTAL FACTORS. SPECIFICALLY, STUDIES HAVE DEMONSTRATED CORRELATIONS BETWEEN PAIN CONDITIONS AND ALTERED DNA METHYLATION PATTERNS. THUS, DNA METHYLATION HAS BEEN REVEALED AS A POSSIBLE MODULATOR OR CONTRIBUTOR TO PAIN CONDITIONS, PROVIDING A POTENTIAL THERAPEUTIC TARGET FOR TREATMENT BY DNA METHYLATION MODIFICATION. TO DEVELOP SUCH TREATMENTS, IT IS NECESSARY TO CLARIFY A WIDE NUMBER OF ASPECTS ON HOW DNA METHYLATION AFFECTS PAIN PERCEPTION; FIRST AND FOREMOST, THE TEMPORAL DYNAMICS. THE OBJECTIVE OF THE PRESENT REVIEW IS TO PROVIDE AN OVERVIEW OF CURRENT KNOWLEDGE ON TEMPORAL DYNAMICS OF DNA METHYLATION IN RESPONSE TO PAIN, AND TO INVESTIGATE IF A TIMEFRAME CAN BE ESTABLISHED BASED ON THE DATA OF CURRENTLY PUBLISHED STUDIES. DATABASES AND DATA TREATMENT: PUBMED, MEDLINE, GOOGLE SCHOLAR AND EMBASE WERE SEARCHED COMPREHENSIVELY FOR STUDIES OF DNA METHYLATION IN NEUROPATHIC, INFLAMMATORY AND ALTERNATIVE ANIMAL PAIN MODELS, AND IN CHRONIC PAIN PATIENTS INCLUDING COMPLEX REGIONAL PAIN SYNDROME, CHRONIC POSTSURGICAL PAIN, CHRONIC WIDESPREAD PAIN, FIBROMYALGIA AND CROHN'S DISEASE. RESULTS: WE IDENTIFIED 34 ARTICLES HIGHLIGHTING VARIATIONS IN TEMPORAL DYNAMICS OF DNA METHYLATION ACROSS SPECIES AND BETWEEN DIFFERENT TYPES OF PAIN. THESE STUDIES REPRESENT A STARTING POINT TO UNCOVER NEW INSIGHTS IN THE DNA METHYLATION TIME COURSE IN PAIN. CONCLUSIONS: NO TIMEFRAME CAN CURRENTLY BE MADE FOR THE DNA METHYLATION RESPONSE TO PAIN IN ANY OF THE REVIEWED CONDITIONS, HIGHLIGHTING AN IMPORTANT FOCUS AREA FOR FUTURE RESEARCH. 2021 14 2526 42 EPIGENETICS APPLIED TO PSYCHIATRY: CLINICAL OPPORTUNITIES AND FUTURE CHALLENGES. PSYCHIATRIC DISORDERS ARE CLINICALLY HETEROGENEOUS AND DEBILITATING CHRONIC DISEASES RESULTING FROM A COMPLEX INTERPLAY BETWEEN GENE VARIANTS AND ENVIRONMENTAL FACTORS. EPIGENETIC PROCESSES, SUCH AS DNA METHYLATION AND HISTONE POSTTRANSLATIONAL MODIFICATIONS, INSTRUCT THE CELL/TISSUE TO CORRECTLY INTERPRET EXTERNAL SIGNALS AND ADJUST ITS FUNCTIONS ACCORDINGLY. GIVEN THAT EPIGENETIC MODIFICATIONS ARE SENSITIVE TO ENVIRONMENT, STABLE, AND REVERSIBLE, EPIGENETIC STUDIES IN PSYCHIATRY COULD REPRESENT A PROMISING APPROACH TO BETTER UNDERSTANDING AND TREATING DISEASE. IN THE PRESENT REVIEW, WE AIM TO DISCUSS THE CLINICAL OPPORTUNITIES AND CHALLENGES ARISING FROM THE EPIGENETIC RESEARCH IN PSYCHIATRY. USING SELECTED EXAMPLES, WE FIRST RECAPITULATE KEY FINDINGS SUPPORTING THE ROLE OF ADVERSE LIFE EVENTS, ALONE OR IN COMBINATION WITH GENETIC RISK, IN EPIGENETIC PROGRAMMING OF NEUROPSYCHIATRIC SYSTEMS. EPIGENETIC STUDIES FURTHER REPORT ENCOURAGING FINDINGS ABOUT THE USE OF METHYLATION CHANGES AS DIAGNOSTIC MARKERS OF DISEASE PHENOTYPE AND PREDICTIVE TOOLS OF PROGRESSION AND RESPONSE TO TREATMENT. THEN WE DISCUSS THE POTENTIAL OF USING TARGETED EPIGENETIC PHARMACOTHERAPY, COMBINED WITH PSYCHOSOCIAL INTERVENTIONS, FOR FUTURE PERSONALIZED MEDICINE FOR PATIENTS. FINALLY, WE REVIEW THE METHODOLOGICAL LIMITATIONS THAT COULD HINDER INTERPRETATION OF EPIGENETIC DATA IN PSYCHIATRY. THEY MAINLY ARISE FROM HETEROGENEITY AT THE INDIVIDUAL AND TISSUE LEVEL AND REQUIRE FUTURE STRATEGIES IN ORDER TO REINFORCE THE BIOLOGICAL RELEVANCE OF EPIGENETIC DATA AND ITS TRANSLATIONAL USE IN PSYCHIATRY. OVERALL, WE SUGGEST THAT EPIGENETICS COULD PROVIDE NEW INSIGHTS INTO A MORE COMPREHENSIVE INTERPRETATION OF MENTAL ILLNESS AND MIGHT EVENTUALLY IMPROVE THE NOSOLOGY, TREATMENT, AND PREVENTION OF PSYCHIATRIC DISORDERS. 2018 15 5028 25 PERSONALIZING PEDIATRIC PAIN MEDICINE: USING POPULATION-SPECIFIC PHARMACOGENETICS, GENOMICS, AND OTHER -OMICS APPROACHES TO PREDICT RESPONSE. PERSONALIZED MEDICINE IS THE SCIENCE OF INDIVIDUALIZED PREVENTION AND THERAPY. THE NOTION THAT "ONE SIZE FITS ALL" HAS BEEN REPLACED BY THE IDEA OF PATIENT-TAILORED HEALTH CARE. WITHIN THIS PARADIGM, THE RESEARCH COMMUNITY HAS TURNED TO EXAMINE GENETIC PREDICTORS OF DISEASE AND TREATMENT RESPONSES. PAIN RESEARCHERS HAVE PRODUCED GENETIC STUDIES OVER THE LAST DECADE THAT EVALUATE THE ASSOCIATION OF GENETIC VARIABILITY WITH PAIN SENSITIVITY AND ANALGESIC RESPONSE. WHILE MOST OF THESE STUDIES HAVE BEEN CONDUCTED AMONG COHORTS OF SUBJECTS OF EUROPEAN DESCENT, SOME HAVE INCLUDED OTHER RACIAL AND ETHNIC GROUPS, PROVIDING EVIDENCE OF VARIABLE RESPONSES TO ANALGESICS. SIMULTANEOUSLY, THERE IS AN INCREASED RECOGNITION REGARDING THE COMPLEXITY OF PAIN RESEARCH, ACKNOWLEDGING THE ADDITIONAL ROLE OF EPIGENETIC, TRANSCRIPTOMIC, PROTEOMIC, AND METABOLOMIC FACTORS IN THE DEVELOPMENT, EXPERIENCE, AND TREATMENT OF PAIN. THIS ARTICLE PROVIDES AN INTRODUCTION TO POPULATION-SPECIFIC PHARMACOGENETICS, PROTEOMICS AND OTHER "-OMICS" TECHNOLOGIES TO PREDICT DRUG RESPONSE TO PAIN MEDICATIONS IN CHILDREN. IT AIMS TO PROVIDE ANESTHESIOLOGISTS WITH THE BASIC KNOWLEDGE TO UNDERSTAND THE POTENTIAL IMPLICATIONS OF GENETIC AND EPIGENETIC FACTORS MANAGING THE PAIN OF PEDIATRIC PATIENTS. 2015 16 6375 44 THE ROLE OF NEURO-IMMUNE INTERACTION IN CHRONIC PAIN CONDITIONS; FUNCTIONAL SOMATIC SYNDROME, NEUROGENIC INFLAMMATION, AND PERIPHERAL NEUROPATHY. FUNCTIONAL SOMATIC SYNDROMES ARE INCREASINGLY DIAGNOSED IN CHRONICALLY ILL PATIENTS PRESENTING WITH AN ARRAY OF SYMPTOMS NOT ATTRIBUTED TO PHYSICAL AILMENTS. CONDITIONS SUCH AS CHRONIC FATIGUE SYNDROME, FIBROMYALGIA SYNDROME, OR IRRITABLE BOWEL SYNDROME ARE COMMON DISORDERS THAT BELONG IN THIS BROAD CATEGORY. SUCH SYNDROMES ARE CHARACTERISED BY THE PRESENCE OF ONE OR MULTIPLE CHRONIC SYMPTOMS INCLUDING WIDESPREAD MUSCULOSKELETAL PAIN, FATIGUE, SLEEP DISORDERS, AND ABDOMINAL PAIN, AMONGST OTHER ISSUES. SYMPTOMS ARE BELIEVED TO RELATE TO A COMPLEX INTERACTION OF BIOLOGICAL AND PSYCHOSOCIAL FACTORS, WHERE A DEFINITE AETIOLOGY HAS NOT BEEN ESTABLISHED. THEORIES SUGGEST CAUSATIVE PATHWAYS BETWEEN THE IMMUNE AND NERVOUS SYSTEMS OF AFFECTED INDIVIDUALS WITH SEVERAL RISK FACTORS IDENTIFIED IN PATIENTS PRESENTING WITH ONE OR MORE FUNCTIONAL SYNDROMES. RISK FACTORS INCLUDING STRESS AND CHILDHOOD TRAUMA ARE NOW RECOGNISED AS IMPORTANT CONTRIBUTORS TO CHRONIC PAIN CONDITIONS. EMOTIONAL, PHYSICAL, AND SEXUAL ABUSE DURING CHILDHOOD IS CONSIDERED A SEVERE STRESSOR HAVING A HIGH PREVALENCE IN FUNCTIONAL SOMATIC SYNDROME SUFFERS. SUCH TRAUMA PERMANENTLY ALTERS THE BIOLOGICAL STRESS RESPONSE OF THE SUFFERS LEADING TO NEUROEXCITATORY AND OTHER NERVE ISSUES ASSOCIATED WITH CHRONIC PAIN IN ADULTS. TRAUMATIC AND CHRONIC STRESS RESULTS IN EPIGENETIC CHANGES IN STRESS RESPONSE GENES, WHICH ULTIMATELY LEADS TO DYSREGULATION OF THE HYPOTHALAMIC-PITUITARY AXIS, THE AUTONOMIC NERVOUS SYSTEM, AND THE IMMUNE SYSTEM MANIFESTING IN A BROAD ARRAY OF SYMPTOMS. IMPORTANTLY, THESE SYSTEMS ARE KNOWN TO BE DYSREGULATED IN PATIENTS SUFFERING FROM FUNCTIONAL SOMATIC SYNDROME. FUNCTIONAL SOMATIC SYNDROMES ARE ALSO HIGHLY PREVALENT CO-MORBIDITIES OF PSYCHIATRIC CONDITIONS, MOOD DISORDERS, AND ANXIETY. CONSEQUENTLY, THIS REVIEW AIMS TO PROVIDE INSIGHT INTO THE ROLE OF THE NERVOUS SYSTEM AND IMMUNE SYSTEM IN CHRONIC PAIN DISORDERS ASSOCIATED WITH THE MUSCULOSKELETAL SYSTEM, AND CENTRAL AND PERIPHERAL NERVOUS SYSTEMS. 2022 17 6026 40 THE BIOLOGY OF STRESS INTOLERANCE IN PATIENTS WITH CHRONIC PAIN-STATE OF THE ART AND FUTURE DIRECTIONS. STRESS HAS BEEN CONSISTENTLY LINKED TO NEGATIVE IMPACTS ON PHYSICAL AND MENTAL HEALTH. MORE SPECIFICALLY, PATIENTS WITH CHRONIC PAIN EXPERIENCE STRESS INTOLERANCE, WHICH IS AN EXACERBATION OR OCCURRENCE OF SYMPTOMS IN RESPONSE TO ANY TYPE OF STRESS. THE PATHOPHYSIOLOGICAL MECHANISMS UNDERLYING THIS PHENOMENON REMAIN UNSOLVED. IN THIS STATE-OF-THE-ART PAPER, WE SUMMARISED THE ROLE OF THE AUTONOMIC NERVOUS SYSTEM (ANS) AND HYPOTHALAMUS-PITUITARY-ADRENAL (HPA) AXIS, THE TWO MAJOR STRESS RESPONSE SYSTEMS IN STRESS INTOLERANCE. WE PROVIDED INSIGHTS INTO SUCH MECHANISMS BASED ON EVIDENCE FROM CLINICAL STUDIES IN BOTH PATIENTS WITH CHRONIC PAIN, SHOWING DYSREGULATED STRESS SYSTEMS, AND HEALTHY CONTROLS SUPPORTED BY PRECLINICAL STUDIES, HIGHLIGHTING THE LINK BETWEEN THESE SYSTEMS AND SYMPTOMS OF STRESS INTOLERANCE. FURTHERMORE, WE EXPLORED THE POSSIBLE REGULATING ROLE FOR (EPI)GENETIC MECHANISMS INFLUENCING THE ANS AND HPA AXIS. THE LINK BETWEEN STRESS AND CHRONIC PAIN HAS BECOME AN IMPORTANT AREA OF RESEARCH AS IT HAS THE POTENTIAL TO INFORM THE DEVELOPMENT OF INTERVENTIONS TO IMPROVE THE QUALITY OF LIFE FOR INDIVIDUALS LIVING WITH CHRONIC PAIN. AS STRESS HAS BECOME A PREVALENT CONCERN IN MODERN SOCIETY, UNDERSTANDING THE CONNECTION BETWEEN STRESS, HPA AXIS, ANS, AND CHRONIC HEALTH CONDITIONS SUCH AS CHRONIC PAIN IS CRUCIAL TO IMPROVE PUBLIC HEALTH AND WELL-BEING. 2023 18 1329 35 DEPRESSION ASSOCIATED WITH DIABETES: FROM PATHOPHYSIOLOGY TO TREATMENT. DIABETES IS A CHRONIC AND PROGRESSIVE SYNDROME COMMONLY ASSOCIATED WITH SEVERAL NEUROPSYCHIATRIC COMORBITIES, OF WHICH DEPRESSION IS THE MOST STUDIED. THE PREVALENCE OF DEPRESSION IS ABOUT TWO OR THREE TIMES HIGHER IN DIABETIC PATIENTS COMPARED TO THE GENERAL POPULATION. IT IS BELIEVED THAT THE DIABETES - DEPRESSION RELATION MAY BE BIDIRECTIONAL, I.E., THE DEPRESSION CAN LEAD TO DIABETES AND CONVERSELY DIABETES COULD FACILITATE THE EMERGENCE OF DEPRESSION. DEPRESSION IS ONE OF THE MOST NEGLECTED SYMPTOMS IN DIABETIC PATIENTS AND IS DIRECTLY LINKED WITH LOWERING OF QUALITY OF LIFE. THE TREATMENT OF DEPRESSION IN THESE PATIENTS IS STILL QUITE INEFFECTIVE AND IN MANY CASES TREATMENTREFRACTORY. FURTHERMORE, SOME OF THE FIRST CHOICE DRUGS USED TO TREAT THE DEPRESSION AFFECT THE BLOOD GLUCOSE CONTROL, AGGRAVATING THE HYPERGLYCEMIC STATE. THESE ISSUES UNDERSCORE THE URGENCY IN STUDIES SEARCHING FOR NEW PHARMACOLOGICAL TARGETS FOR THE TREATMENT OF DEPRESSION ASSOCIATED WITH DIABETES. FOR THIS, A BETTER UNDERSTANDING OF THE PATHOPHYSIOLOGY THAT RELATES THIS COMORBIDITY BECOMES CRITICAL. IN THIS RESPECT, THIS REVIEW WILL FOCUS ON SOME HYPOTHESES THAT HAVE BEEN PROPOSED TO EXPLAIN THE MECHANISMS UNDERLYING DEPRESSION ASSOCIATED WITH DIABETES, HIGHLIGHTING THE TREATMENT OPTIONS CURRENTLY AVAILABLE AND THEIR LIMITATIONS. AMONG THESE HYPOTHESES, WE WILL POINT OUT THE HYPERGLYCEMIA AS A PRIMARY METABOLIC CAUSE OF THE DEPRESSION DEVELOPMENT, THE INVOLVEMENT OF THE DYSREGULATION OF HYPOTHALAMIC PITUITARY-ADRENAL (HPA) AXIS AND OF NEUROTRANSMITTER SYSTEMS, SPECIALLY MONOAMINERGIC SYSTEM. BESIDES, THE ROLE OF OXIDATIVE STRESS, NEUROINFLAMMATION AND CELL DEATH, ESPECIALLY IN HIPPOCAMPUS AND PREFRONTAL CORTEX, BRAIN AREAS IMPORTANT FOR THE MEDIATION AND MODULATION OF EMOTIONAL BEHAVIOR WILL ALSO BE DISCUSSED. FINALLY, WE WILL BRING UP THE INFLUENCE OF THE EPIGENETIC REGULATION WITH RESPECT TO NEUROPSYCHIATRIC DISORDERS. 2016 19 1736 39 EARLY DETECTION AND PREVENTION OF SCHIZOPHRENIC PSYCHOSIS-A REVIEW. PSYCHOTIC DISORDERS OFTEN RUN A CHRONIC COURSE AND ARE ASSOCIATED WITH A CONSIDERABLE EMOTIONAL AND SOCIAL IMPACT FOR PATIENTS AND THEIR RELATIVES. THEREFORE, EARLY RECOGNITION, COMBINED WITH THE POSSIBILITY OF PREVENTIVE INTERVENTION, IS URGENTLY WARRANTED SINCE THE DURATION OF UNTREATED PSYCHOSIS (DUP) SIGNIFICANTLY DETERMINES THE FURTHER COURSE OF THE DISEASE. IN ADDITION TO ESTABLISHED DIAGNOSTIC TOOLS, NEUROBIOLOGICAL FACTORS IN THE DEVELOPMENT OF SCHIZOPHRENIC PSYCHOSES ARE INCREASINGLY BEING INVESTIGATED. IT IS SHOWN THAT NUMEROUS MOLECULAR ALTERATIONS ALREADY EXIST BEFORE THE CLINICAL ONSET OF THE DISEASE. AS SCHIZOPHRENIC PSYCHOSES ARE NOT ELICITED BY A SINGLE MUTATION IN THE DEOXYRIBONUCLEIC ACID (DNA) SEQUENCE, EPIGENETICS LIKELY CONSTITUTE THE MISSING LINK BETWEEN ENVIRONMENTAL INFLUENCES AND DISEASE DEVELOPMENT AND COULD POTENTIALLY SERVE AS A BIOMARKER. THE RESULTS FROM TRANSCRIPTOMIC AND PROTEOMIC STUDIES POINT TO A DYSREGULATED IMMUNE SYSTEM, LIKELY EVOKED BY EPIGENETIC ALTERATIONS. DESPITE THE INCREASING KNOWLEDGE OF THE NEUROBIOLOGICAL MECHANISMS INVOLVED IN THE DEVELOPMENT OF PSYCHOTIC DISORDERS, FURTHER RESEARCH EFFORTS WITH LARGE POPULATION-BASED STUDY DESIGNS ARE NEEDED TO IDENTIFY SUITABLE BIOMARKERS. IN CONCLUSION, A COMBINATION OF BLOOD EXAMINATIONS, FUNCTIONAL IMAGING TECHNIQUES, ELECTROENCEPHALOGRAPHY (EEG) INVESTIGATIONS AND POLYGENIC RISK SCORES SHOULD BE CONSIDERED AS THE BASIS FOR PREDICTING HOW SUBJECTS WILL TRANSITION INTO MANIFEST PSYCHOSIS. 2021 20 6414 40 THE STRESSED SYNAPSE 2.0: PATHOPHYSIOLOGICAL MECHANISMS IN STRESS-RELATED NEUROPSYCHIATRIC DISORDERS. STRESS IS A PRIMARY RISK FACTOR FOR SEVERAL NEUROPSYCHIATRIC DISORDERS. EVIDENCE FROM PRECLINICAL MODELS AND CLINICAL STUDIES OF DEPRESSION HAVE REVEALED AN ARRAY OF STRUCTURAL AND FUNCTIONAL MALADAPTIVE CHANGES, WHEREBY ADVERSE ENVIRONMENTAL FACTORS SHAPE THE BRAIN. THESE CHANGES, OBSERVED FROM THE MOLECULAR AND TRANSCRIPTIONAL LEVELS THROUGH TO LARGE-SCALE BRAIN NETWORKS, TO THE BEHAVIOURS REVEAL A COMPLEX MATRIX OF INTERRELATED PATHOPHYSIOLOGICAL PROCESSES THAT DIFFER BETWEEN SEXES, PROVIDING INSIGHT INTO THE POTENTIAL UNDERPINNINGS OF THE SEX BIAS OF NEUROPSYCHIATRIC DISORDERS. ALTHOUGH MANY PRECLINICAL STUDIES USE CHRONIC STRESS PROTOCOLS, LONG-TERM CHANGES ARE ALSO INDUCED BY ACUTE EXPOSURE TO TRAUMATIC STRESS, OPENING A PATH TO IDENTIFY DETERMINANTS OF RESILIENT VERSUS SUSCEPTIBLE RESPONSES TO BOTH ACUTE AND CHRONIC STRESS. EPIGENETIC REGULATION OF GENE EXPRESSION HAS EMERGED AS A KEY PLAYER UNDERLYING THE PERSISTENT IMPACT OF STRESS ON THE BRAIN. INDEED, HISTONE MODIFICATION, DNA METHYLATION AND MICRORNAS ARE CLOSELY INVOLVED IN MANY ASPECTS OF THE STRESS RESPONSE AND REVEAL THE GLUTAMATE SYSTEM AS A KEY PLAYER. THE SUCCESS OF KETAMINE HAS STIMULATED A WHOLE LINE OF RESEARCH AND DEVELOPMENT ON DRUGS DIRECTLY OR INDIRECTLY TARGETING GLUTAMATE FUNCTION. HOWEVER, THE CHALLENGE OF TRANSLATING THE EMERGING UNDERSTANDING OF STRESS PATHOPHYSIOLOGY INTO EFFECTIVE CLINICAL TREATMENTS REMAINS A MAJOR CHALLENGE. 2022