1 1722 100 DYSREGULATION OF BRAIN DOPAMINE SYSTEMS IN MAJOR DEPRESSIVE DISORDER. MAJOR DEPRESSIVE DISORDER (MDD OR DEPRESSION) IS A DEBILITATING NEUROPSYCHIATRIC SYNDROME WITH GENETIC, EPIGENETIC, AND ENVIRONMENTAL CONTRIBUTIONS. DEPRESSION IS ONE OF THE LARGEST CONTRIBUTORS TO CHRONIC DISEASE BURDEN; IT AFFECTS MORE THAN ONE IN SIX INDIVIDUALS IN THE UNITED STATES. A WIDE ARRAY OF CELLULAR AND MOLECULAR MODIFICATIONS DISTRIBUTED ACROSS A VARIETY OF NEURONAL PROCESSES AND CIRCUITS UNDERLIE THE PATHOPHYSIOLOGY OF DEPRESSION-NO ESTABLISHED MECHANISM CAN EXPLAIN ALL ASPECTS OF THE DISEASE. MDD SUFFERS FROM A VAST TREATMENT GAP WORLDWIDE, AND LARGE NUMBERS OF INDIVIDUALS WHO REQUIRE TREATMENT DO NOT RECEIVE ADEQUATE CARE. THIS MINI-REVIEW FOCUSES ON DYSREGULATION OF BRAIN DOPAMINE (DA) SYSTEMS IN THE PATHOPHYSIOLOGY OF MDD AND DESCRIBING NEW CELLULAR TARGETS FOR POTENTIAL MEDICATION DEVELOPMENT FOCUSED ON DA-MODULATED MICRO-CIRCUITS. WE ALSO EXPLORE HOW NEURODEVELOPMENTAL FACTORS MAY MODIFY RISK FOR LATER EMERGENCE OF MDD, POSSIBLY THROUGH DOPAMINERGIC SUBSTRATES IN THE BRAIN. 2021 2 225 31 ACUTE STRESS-INDUCED EPIGENETIC MODULATIONS AND THEIR POTENTIAL PROTECTIVE ROLE TOWARD DEPRESSION. PSYCHIATRIC DISORDERS ENTAIL MALADAPTIVE PROCESSES IMPAIRING INDIVIDUALS' ABILITY TO APPROPRIATELY INTERFACE WITH ENVIRONMENT. AMONG THEM, DEPRESSION IS CHARACTERIZED BY DIVERSE DEBILITATING SYMPTOMS INCLUDING HOPELESSNESS AND ANHEDONIA, DRAMATICALLY IMPACTING THE PROPENSITY TO LIVE A SOCIAL AND ACTIVE LIFE AND SERIOUSLY AFFECTING WORKING CAPABILITY. RELEVANTLY, BESIDES GENETIC PREDISPOSITION, FOREMOST RISK FACTORS ARE STRESS-RELATED, SUCH AS EXPERIENCING CHRONIC PSYCHOSOCIAL STRESS-INCLUDING BULLYING, MOBBING AND ABUSE-, AND UNDERGOING ECONOMIC CRISIS OR CHRONIC ILLNESSES. IN THE LAST FEW YEARS THE FIELD OF EPIGENETICS PROMISED TO UNDERSTAND CORE MECHANISMS OF GENE-ENVIRONMENT CROSSTALK, CONTRIBUTING TO GET INTO PATHOGENIC PROCESSES OF MANY DISORDERS HIGHLY INFLUENCED BY STRESSFUL LIFE CONDITIONS. HOWEVER, STILL VERY LITTLE IS KNOWN ABOUT MECHANISMS THAT TUNE GENE EXPRESSION TO ADAPT TO THE EXTERNAL MILIEU. IN THIS PERSPECTIVE ARTICLE, WE DISCUSS A SET OF PROTECTIVE, FUNCTIONALLY CONVERGENT EPIGENETIC PROCESSES INDUCED BY ACUTE STRESS IN THE RODENT HIPPOCAMPUS AND DEVOTED TO THE NEGATIVE MODULATION OF STRESS-INDUCED IMMEDIATE EARLY GENES (IEGS) TRANSCRIPTION, HINDERING STRESS-DRIVEN MORPHOSTRUCTURAL MODIFICATIONS OF CORTICOLIMBIC CIRCUITRY. WE ALSO SUGGEST THAT CHRONIC STRESS DAMAGING PROTECTIVE EPIGENETIC MECHANISMS, COULD BIAS THE FUNCTIONAL TRAJECTORY OF STRESS-INDUCED NEURONAL MORPHOSTRUCTURAL MODIFICATION FROM ADAPTIVE TO MALADAPTIVE, CONTRIBUTING TO THE ONSET OF DEPRESSION IN VULNERABLE INDIVIDUALS. A BETTER UNDERSTANDING OF THE EPIGENETIC RESPONSE TO STRESS WILL BE PIVOTAL TO NEW AVENUES OF THERAPEUTIC INTERVENTION TO TREAT DEPRESSION, ESPECIALLY IN LIGHT OF LIMITED EFFICACY OF AVAILABLE ANTIDEPRESSANT DRUGS. 2018 3 2288 40 EPIGENETIC REGULATION IN MAJOR DEPRESSION AND OTHER STRESS-RELATED DISORDERS: MOLECULAR MECHANISMS, CLINICAL RELEVANCE AND THERAPEUTIC POTENTIAL. MAJOR DEPRESSIVE DISORDER (MDD) IS A CHRONIC, GENERALLY EPISODIC AND DEBILITATING DISEASE THAT AFFECTS AN ESTIMATED 300 MILLION PEOPLE WORLDWIDE, BUT ITS PATHOGENESIS IS POORLY UNDERSTOOD. THE HERITABILITY ESTIMATE OF MDD IS 30-40%, SUGGESTING THAT GENETICS ALONE DO NOT ACCOUNT FOR MOST OF THE RISK OF MAJOR DEPRESSION. ANOTHER FACTOR KNOWN TO ASSOCIATE WITH MDD INVOLVES ENVIRONMENTAL STRESSORS SUCH AS CHILDHOOD ADVERSITY AND RECENT LIFE STRESS. RECENT STUDIES HAVE EMERGED TO SHOW THAT THE BIOLOGICAL IMPACT OF ENVIRONMENTAL FACTORS IN MDD AND OTHER STRESS-RELATED DISORDERS IS MEDIATED BY A VARIETY OF EPIGENETIC MODIFICATIONS. THESE EPIGENETIC MODIFICATION ALTERATIONS CONTRIBUTE TO ABNORMAL NEUROENDOCRINE RESPONSES, NEUROPLASTICITY IMPAIRMENT, NEUROTRANSMISSION AND NEUROGLIA DYSFUNCTION, WHICH ARE INVOLVED IN THE PATHOPHYSIOLOGY OF MDD. FURTHERMORE, EPIGENETIC MARKS HAVE BEEN ASSOCIATED WITH THE DIAGNOSIS AND TREATMENT OF MDD. THE EVALUATION OF EPIGENETIC MODIFICATIONS HOLDS PROMISE FOR FURTHER UNDERSTANDING OF THE HETEROGENEOUS ETIOLOGY AND COMPLEX PHENOTYPES OF MDD, AND MAY IDENTIFY NEW THERAPEUTIC TARGETS. HERE, WE REVIEW PRECLINICAL AND CLINICAL EPIGENETIC FINDINGS, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, NONCODING RNA, RNA MODIFICATION, AND CHROMATIN REMODELING FACTOR IN MDD. IN ADDITION, WE ELABORATE ON THE CONTRIBUTION OF THESE EPIGENETIC MECHANISMS TO THE PATHOLOGICAL TRAIT VARIABILITY IN DEPRESSION AND DISCUSS HOW SUCH MECHANISMS CAN BE EXPLOITED FOR THERAPEUTIC PURPOSES. 2023 4 4848 28 OPIOID-INDUCED STRUCTURAL AND FUNCTIONAL PLASTICITY OF MEDIUM-SPINY NEURONS IN THE NUCLEUS ACCUMBENS. OPIOID USE DISORDER (OUD) IS A CHRONIC RELAPSING CLINICAL CONDITION WITH TREMENDOUS MORBIDITY AND MORTALITY THAT FREQUENTLY PERSISTS, DESPITE TREATMENT, DUE TO AN INDIVIDUAL'S UNDERLYING PSYCHOLOGICAL, NEUROBIOLOGICAL, AND GENETIC VULNERABILITIES. EVIDENCE SUGGESTS THAT THESE VULNERABILITIES MAY HAVE NEUROCHEMICAL, CELLULAR, AND MOLECULAR BASES. KEY NEUROPLASTIC EVENTS WITHIN THE MESOCORTICOLIMBIC SYSTEM THAT EMERGE THROUGH CHRONIC EXPOSURE TO OPIOIDS MAY HAVE A DETERMINATIVE INFLUENCE ON BEHAVIORAL SYMPTOMS ASSOCIATED WITH OUD. IN PARTICULAR, STRUCTURAL AND FUNCTIONAL ALTERATIONS IN THE DENDRITIC SPINES OF MEDIUM SPINY NEURONS (MSNS) WITHIN THE NUCLEUS ACCUMBENS (NAC) AND ITS DOPAMINERGIC PROJECTIONS FROM THE VENTRAL TEGMENTAL AREA (VTA) ARE BELIEVED TO FACILITATE THESE BEHAVIORAL SEQUELAE. ADDITIONALLY, GLUTAMATERGIC NEURONS FROM THE PREFRONTAL CORTEX, THE BASOLATERAL AMYGDALA, THE HIPPOCAMPUS, AND THE THALAMUS PROJECT TO THESE SAME MSNS, PROVIDING AN ENRICHED TARGET FOR SYNAPTIC PLASTICITY. HERE, WE REVIEW LITERATURE RELATED TO NEUROADAPTATIONS IN NAC MSNS FROM DOPAMINERGIC AND GLUTAMATERGIC PATHWAYS IN OUD. WE ALSO DESCRIBE NEW FINDINGS RELATED TO TRANSCRIPTIONAL, EPIGENETIC, AND MOLECULAR MECHANISMS IN MSN PLASTICITY IN THE DIFFERENT STAGES OF OUD. 2021 5 4632 20 NEUROIMAGING GENETIC APPROACHES TO POSTTRAUMATIC STRESS DISORDER. NEUROIMAGING GENETIC STUDIES THAT ASSOCIATE GENETIC AND EPIGENETIC VARIATION WITH NEURAL ACTIVITY OR STRUCTURE PROVIDE AN OPPORTUNITY TO LINK GENES TO PSYCHIATRIC DISORDERS, OFTEN BEFORE PSYCHOPATHOLOGY IS DISCERNABLE IN BEHAVIOR. HERE WE REVIEW NEUROIMAGING GENETICS STUDIES WITH PARTICIPANTS WHO HAVE POSTTRAUMATIC STRESS DISORDER (PTSD). RESULTS SHOW THAT GENES RELATED TO THE PHYSIOLOGICAL STRESS RESPONSE (E.G., GLUCOCORTICOID RECEPTOR AND ACTIVITY, NEUROENDOCRINE RELEASE), LEARNING AND MEMORY (E.G., PLASTICITY), MOOD, AND PAIN PERCEPTION ARE TIED TO NEURAL INTERMEDIATE PHENOTYPES ASSOCIATED WITH PTSD. THESE GENES ARE ASSOCIATED WITH AND SOMETIMES PREDICT NEURAL STRUCTURE AND FUNCTION IN AREAS INVOLVED IN ATTENTION, EXECUTIVE FUNCTION, MEMORY, DECISION-MAKING, EMOTION REGULATION, SALIENCE OF POTENTIAL THREATS, AND PAIN PERCEPTION. EVIDENCE SUGGESTS THESE RISK POLYMORPHISMS AND NEURAL INTERMEDIATE PHENOTYPES ARE VULNERABILITIES TOWARD DEVELOPING PTSD IN THE AFTERMATH OF TRAUMA, OR VULNERABILITIES TOWARD PARTICULAR SYMPTOMS ONCE PTSD HAS DEVELOPED. WORK DISTINGUISHING BETWEEN THE RE-EXPERIENCING AND DISSOCIATIVE SUB-TYPES OF PTSD, AND EXAMINING OTHER PTSD SYMPTOM CLUSTERS IN ADDITION TO THE RE-EXPERIENCING AND HYPERAROUSAL SYMPTOMS, WILL FURTHER CLARIFY NEUROBIOLOGICAL MECHANISMS AND INCONSISTENT FINDINGS. FURTHERMORE, AN EXCITING POSSIBILITY IS THAT GENETIC ASSOCIATIONS WITH PTSD MAY EVENTUALLY BE UNDERSTOOD THROUGH DIFFERENTIAL INTERMEDIATE PHENOTYPES OF NEURAL CIRCUIT STRUCTURE AND FUNCTION, POSSIBLY UNDERLYING THE DIFFERENT SYMPTOM CLUSTERS SEEN WITHIN PTSD. 2016 6 2572 29 EPIGENETICS OF DEPRESSION. MAJOR DEPRESSIVE DISORDER (MDD) IS A LEADING CAUSE OF DISABILITY WORLDWIDE AND IS ASSOCIATED WITH POOR PSYCHOLOGICAL, MEDICAL, AND SOCIOECONOMIC OUTCOMES. ALTHOUGH MUCH HAS BEEN LEARNED ABOUT THE ETIOLOGY AND TREATMENT OPTIONS OF MDD OVER THE PAST DECADE, THERE REMAIN UNANSWERED QUESTIONS THAT POSE CHALLENGES TO IMPROVING ACUTE AND CHRONIC OUTCOMES FOR THOSE WITH MDD. MDD IS A CLINICALLY HETEROGENEOUS DISORDER. GENETIC STUDIES TO DATE HAVE INDICATED A NUMBER OF GENES, INCLUDING TRANSPORTERS, NEUROTRANSMITTERS, NEUROTROPHINS, AND THEIR ASSOCIATED SIGNALING NETWORKS THAT MAY PREDISPOSE INDIVIDUALS TO MDD AND MAY ALSO PREDICT TREATMENT OUTCOMES. HOWEVER, TWIN STUDIES INDICATE THAT GENES ACCOUNT FOR ONLY A SMALL DEGREE OF THE VARIATION IN MDD. THUS, OTHER MECHANISMS, THROUGH EPIGENETIC MARKS, MAY ACT TO FORM A MOLECULAR MEMORY OF PREVIOUS GENE-TO-ENVIRONMENT INTERACTIONS AND TO ESTABLISH VULNERABILITIES (OR, CONVERSELY, RESISTANCE) TO MDD. CURRENT EVIDENCE SUPPORTS A ROLE FOR PRE-, PERI-, AND EARLY POSTNATAL ADVERSITIES AND STRESSFUL LIFE EVENTS INTO ADULTHOOD AFFECTING EPIGENETIC PATTERNS, PROVIDING A MECHANISTIC FOUNDATION TO DEVELOP EPIGENETIC MARKS AS BIOMARKERS FOR MDD. THIS REVIEW PRESENTS THE EVIDENCE SUPPORTING A ROLE FOR EPIGENETIC EFFECTS IN MDD AND IN TREATMENT RESPONSE. WE ALSO DISCUSS THE CONTROVERSY BEHIND MODULATING EPIGENETIC MECHANISMS IN LONG-TERM ANTIDEPRESSANT PHARMACOTHERAPY. 2014 7 6375 27 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 8 632 30 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 9 3361 28 HISTONE LYSINE DEMETHYLASE JMJD2D/KDM4D AND FAMILY MEMBERS MEDIATE EFFECTS OF CHRONIC SOCIAL DEFEAT STRESS ON MOUSE HIPPOCAMPAL NEUROGENESIS AND MOOD DISORDERS. DEPRESSION, ANXIETY AND RELATED MOOD DISORDERS ARE MAJOR PSYCHIATRIC ILLNESSES WORLDWIDE, AND CHRONIC STRESS APPEARS TO BE ONE OF THE PRIMARY UNDERLYING CAUSES. THERAPEUTICS TO TREAT THESE DEBILITATING DISORDERS WITHOUT A RELAPSE ARE LIMITED DUE TO THE INCOMPLETE MOLECULAR UNDERSTANDING OF THEIR ETIOPATHOLOGY. IN ADDITION TO THE WELL-STUDIED GENETIC COMPONENT, RESEARCH IN THE PAST TWO DECADES HAS IMPLICATED DIVERSE EPIGENETIC MECHANISMS IN MEDIATING THE NEGATIVE EFFECTS OF CHRONIC STRESSFUL EVENTS ON NEURAL CIRCUITS. THIS INCLUDES THE COGNITIVE CIRCUITRY, WHERE THE DYNAMIC HIPPOCAMPAL DENTATE GYRUS (DG) NEUROGENESIS GETS AFFECTED IN DEPRESSION AND RELATED AFFECTIVE DISORDERS. MOST OF THESE EPIGENETIC STUDIES HAVE FOCUSED ON THE IMPACT OF ACETYLATION/DEACETYLATION AND METHYLATION OF SEVERAL HISTONE LYSINE RESIDUES ON NEURAL GENE EXPRESSION. HOWEVER, THERE IS A DEARTH OF INVESTIGATION INTO THE ROLE OF DEMETHYLATION OF THESE LYSINE RESIDUES IN CHRONIC STRESS-INDUCED CHANGES IN NEUROGENESIS THAT RESULTS IN ALTERED BEHAVIOUR. HERE, USING THE CHRONIC SOCIAL DEFEAT STRESS (CSDS) PARADIGM TO INDUCE DEPRESSION AND ANXIETY IN C57BL/6 MICE AND EX VIVO DG NEURAL STEM/PROGENITOR CELL (NSCS/NPCS) CULTURE WE SHOW THE ROLE OF THE MEMBERS OF THE JMJD2/KDM4 FAMILY OF HISTONE LYSINE DEMETHYLASES (KDMS) IN MEDIATING STRESS-INDUCED CHANGES IN DG NEUROGENESIS AND MOOD DISORDERS. THE STUDY SUGGESTS A CRITICAL ROLE OF JMJD2D IN DG NEUROGENESIS. ALTERED ENRICHMENT OF JMJD2D ON THE PROMOTERS OF ID2 (INHIBITOR OF DIFFERENTIATION 2) AND SOX2 (SRY-BOX TRANSCRIPTION FACTOR 2) WAS OBSERVED DURING PROLIFERATION AND DIFFERENTIATION OF NSCS/NPCS OBTAINED FROM THE DG. THIS WOULD AFFECT THE DEMETHYLATION OF REPRESSIVE EPIGENETIC MARK H3K9, THUS ACTIVATING OR REPRESSING THESE AND POSSIBLY OTHER GENES INVOLVED IN REGULATING PROLIFERATION AND DIFFERENTIATION OF DG NSCS/NPCS. TREATMENT OF THE NSCS/NPCS CULTURE WITH DIMETHYLOXALLYL GLYCINE (DMOG), AN INHIBITOR OF JMJDS, LED TO ATTENUATION IN THEIR PROLIFERATION CAPACITY. ADDITIONALLY, SYSTEMIC ADMINISTRATION OF DMOG IN MICE FOR 10 DAYS INDUCED DEPRESSION-LIKE AND ANXIETY-LIKE PHENOTYPE WITHOUT ANY STRESS EXPOSURE. 2020 10 3606 30 IMPROVING TREATMENT OF NEURODEVELOPMENTAL DISORDERS: RECOMMENDATIONS BASED ON PRECLINICAL STUDIES. INTRODUCTION: NEURODEVELOPMENTAL DISORDERS (NDDS) ARE COMMON AND SEVERELY DEBILITATING. THEIR CHRONIC NATURE AND RELIANCE ON BOTH GENETIC AND ENVIRONMENTAL FACTORS MAKES STUDYING NDDS AND THEIR TREATMENT A CHALLENGING TASK. AREAS COVERED: HEREIN, THE AUTHORS DISCUSS THE NEUROBIOLOGICAL MECHANISMS OF NDDS, AND PRESENT RECOMMENDATIONS ON THEIR TRANSLATIONAL RESEARCH AND THERAPY, OUTLINED BY THE INTERNATIONAL STRESS AND BEHAVIOR SOCIETY. VARIOUS DRUGS CURRENTLY PRESCRIBED TO TREAT NDDS ALSO REPRESENT A HIGHLY DIVERSE GROUP. ACTING ON VARIOUS NEUROTRANSMITTER AND PHYSIOLOGICAL SYSTEMS, THESE DRUGS OFTEN LACK SPECIFICITY OF ACTION, AND ARE COMMONLY USED TO TREAT MULTIPLE OTHER PSYCHIATRIC CONDITIONS. THERE HAS ALSO BEEN RELATIVELY LITTLE PROGRESS IN THE DEVELOPMENT OF NOVEL MEDICATIONS TO TREAT NDDS. BASED ON CLINICAL, PRECLINICAL AND TRANSLATIONAL MODELS OF NDDS, OUR RECOMMENDATIONS COVER A WIDE RANGE OF METHODOLOGICAL APPROACHES AND CONCEPTUAL STRATEGIES. EXPERT OPINION: TO IMPROVE PHARMACOTHERAPY AND DRUG DISCOVERY FOR NDDS, WE NEED A STRONGER EMPHASIS ON TARGETING MULTIPLE ENDOPHENOTYPES, A BETTER DISSECTION OF GENETIC/EPIGENETIC FACTORS OR "HIDDEN HERITABILITY," AND A CAREFUL CONSIDERATION OF POTENTIAL DEVELOPMENTAL/TROPHIC ROLES OF BRAIN NEUROTRANSMITTERS. THE VALIDITY OF ANIMAL NDD MODELS CAN BE IMPROVED THROUGH DISCOVERY OF NOVEL (BEHAVIORAL, PHYSIOLOGICAL AND NEUROIMAGING) BIOMARKERS, APPLYING PROPER ENVIRONMENTAL ENRICHMENT, WIDENING THE SPECTRUM OF MODEL ORGANISMS, TARGETING DEVELOPMENTAL TRAJECTORIES OF NDD-RELATED BEHAVIORS AND COMORBID CONDITIONS BEYOND TRADITIONAL NDDS. WHILE THESE RECOMMENDATIONS CANNOT BE ADDRESSED ALL IN ONCE, OUR INCREASED UNDERSTANDING OF NDD PATHOBIOLOGY MAY TRIGGER INNOVATIVE CROSS-DISCIPLINARY RESEARCH EXPANDING BEYOND TRADITIONAL METHODS AND CONCEPTS. 2016 11 1179 24 CONVERGENCE AND DIVERGENCE IN THE ETIOLOGY OF MYELIN IMPAIRMENT IN PSYCHIATRIC DISORDERS AND DRUG ADDICTION. IMPAIRMENT OF OLIGODENDROGLIA (OL)-DEPENDENT MYELINATION IN THE CENTRAL NERVOUS SYSTEM (CNS) IS A REMARKABLE PARALLEL RECENTLY IDENTIFIED IN MAJOR PSYCHIATRIC DISORDERS AND CHRONIC DRUG ABUSE. NEUROIMAGING AND NEUROPATHOLOGICAL STUDIES REVEALED MYELIN DEFECTS AND MICROARRAY-PROFILING ANALYSIS DEMONSTRATED ABERRANT EXPRESSION OF MYELIN-RELATED GENES IN SCHIZOPHRENIA (SZ), BIPOLAR DISORDER (BD), MAJOR DEPRESSIVE DISORDER (MDD) AND COCAINE ADDICTION. HOWEVER, THE ETIOLOGY UNDERLYING MYELIN IMPAIRMENT IN THESE CLINICALLY DISTINCT SUBJECTS REMAINS ELUSIVE. THIS ARTICLE REVIEWS MYELIN IMPAIRMENT IN LINE WITH DOPAMINERGIC DYSFUNCTION, A PRIME NEUROPATHOPHYSIOLOGICAL TRAIT SHARED IN PSYCHIATRIC DISORDERS AND DRUG ABUSE, AS WELL AS THE GENETIC AND EPIGENETIC ALTERATIONS ASSOCIATED WITH THESE DISEASES. THE CURRENT FINDINGS SUPPORT THE HYPOTHESIS THAT ABERRANT DOPAMINE (DA) ACTION ON OLS IS A COMMON PATHOLOGIC MECHANISM FOR MYELIN IMPAIRMENT IN THE AFOREMENTIONED MENTAL MORBIDITIES, WHEREAS INHERITED GENETIC VARIATIONS THAT SPECIFICALLY AFFECT OL DEVELOPMENT AND MYELINOGENESIS MAY FURTHER INCREASE MYELIN VULNERABILITY IN PSYCHIATRIC DISORDERS. IMPORTANTLY, OL DEFECT IS NOT ONLY A PATHOLOGICAL CONSEQUENCE BUT ALSO A CAUSATIVE FACTOR FOR DOPAMINERGIC DYSFUNCTION. HENCE, MYELIN IMPAIRMENT IS A KEY FACTOR IN THE PATHOGENIC LOOP OF PSYCHIATRIC DISEASES AND DRUG ADDICTION. 2008 12 6676 30 USING EPIGENETIC TOOLS TO INVESTIGATE ANTIDEPRESSANT RESPONSE. MAJOR DEPRESSIVE DISORDER IS A CHRONIC AND DEBILITATING ILLNESS. IT IS MOST COMMONLY TREATED WITH ANTIDEPRESSANT DRUGS, HOWEVER, AS THE MAJORITY OF PATIENTS DO NOT RESPOND ON THEIR FIRST TRIAL OR FOLLOWING SEVERAL ADEQUATE TRIALS, THERE IS GREAT INTEREST IN IDENTIFYING BIOLOGICAL FACTORS THAT MAY HELP SELECT THE MOST APPROPRIATE TREATMENT FOR EACH PATIENT AND IN UNDERSTANDING BIOLOGICAL PROCESSES THAT MEDIATE TREATMENT RESPONSE. EPIGENETIC FACTORS, SUCH AS NON-CODING RNAS (NCRNAS), HOLD POTENTIAL AS BIOMARKERS OF ANTIDEPRESSANT RESPONSE. IN THIS CHAPTER, WE REVIEW KEY METHODOLOGICAL CONSIDERATIONS WHEN INVESTIGATING NCRNA BIOMARKERS, INCLUDING BIOLOGICAL SAMPLES AND TECHNOLOGIES WHICH HAVE BEEN USED IN THESE STUDIES. SECONDLY, WE SUMMARIZE FINDINGS FROM STUDIES INVESTIGATING NCRNAS IN ANTIDEPRESSANT TREATMENT RESPONSE. FINALLY, WE DISCUSS SOME OF THE FUTURE DIRECTIONS WHICH WILL BE NECESSARY FOR THE DEVELOPMENT OF CLINICALLY RELEVANT EPIGENETIC TOOLS. 2018 13 2011 30 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 14 6827 24 [GILLES DE LA TOURETTE'S DISEASE. SYMPTOMS, ETIOPATHOGENESIS AND THERAPEUTIC APPROACHES]. THE GILLES DE LA TOURETTE SYNDROME IS A USUALLY CHRONIC NEUROPSYCHIATRIC DISORDER WITH AN EARLY CHILDHOOD ONSET FEATURING MAINLY MOTOR AND VOCAL TICS. IT SEEMS THAT STRONG GENETIC FACTORS MAKE A MAJOR CONTRIBUTION TO THE ETIOLOGY OF THIS DISORDER, BUT THERE ARE ALSO CLUES THAT EPIGENETIC FACTORS ARE INVOLVED IN THE PATHOGENESIS OF TOURETTE'S SYNDROME, SUCH AS MATERNAL STRESS DURING PREGNANCY, BIRTH COMPLICATIONS AND HORMONAL INFLUENCES. FIRST IN LINE FOR ADEQUATE TREATMENT ARE NEUROLEPTIC COMPOUNDS OF HIGH POTENCY, BESIDES, SEVERAL OTHER PSYCHOACTIVE DRUGS HAVE SHOWN SOME THERAPEUTIC EFFECTS. LESS EVIDENT IS THE EFFICACY OF NEUROSURGICAL AND PSYCHOTHERAPEUTIC INTERVENTIONS. 1997 15 6174 37 THE HIPPOCAMPUS, NEUROTROPHIC FACTORS AND DEPRESSION: POSSIBLE IMPLICATIONS FOR THE PHARMACOTHERAPY OF DEPRESSION. DEPRESSION IS A PREVALENT, HIGHLY DEBILITATING MENTAL DISORDER AFFECTING UP TO 15% OF THE POPULATION AT LEAST ONCE IN THEIR LIFETIME, WITH HUGE COSTS FOR SOCIETY. NEUROBIOLOGICAL MECHANISMS OF DEPRESSION ARE STILL NOT WELL KNOWN, ALTHOUGH THERE IS CONSENSUS ABOUT INTERPLAY BETWEEN GENETIC AND ENVIRONMENTAL FACTORS. ANTIDEPRESSANT MEDICATIONS ARE FREQUENTLY USED IN DEPRESSION, BUT AT LEAST 50% OF PATIENTS ARE POOR RESPONDERS, EVEN TO MORE RECENTLY DISCOVERED MEDICATIONS. FURTHERMORE, CLINICAL RESPONSE ONLY OCCURS FOLLOWING WEEKS TO MONTHS OF TREATMENT AND ONLY CHRONIC TREATMENT IS EFFECTIVE, SUGGESTING THAT ACTIONS BEYOND THE RAPIDLY OCCURRING EFFECT OF ENHANCING MONOAMINERGIC SYSTEMS, SUCH AS ADAPTATION OF THESE SYSTEMS, ARE RESPONSIBLE FOR THE EFFECTS OF ANTIDEPRESSANTS. RECENT STUDIES INDICATE THAT AN IMPAIRMENT OF SYNAPTIC PLASTICITY (NEUROGENESIS, AXON BRANCHING, DENDRITOGENESIS AND SYNAPTOGENESIS) IN SPECIFIC AREAS OF THE CNS, PARTICULARLY THE HIPPOCAMPUS, MAY BE A CORE FACTOR IN THE PATHOPHYSIOLOGY OF DEPRESSION. THE ABNORMAL NEURAL PLASTICITY MAY BE RELATED TO ALTERATIONS IN THE LEVELS OF NEUROTROPHIC FACTORS, NAMELY BRAIN-DERIVED NEUROTROPHIC FACTOR (BDNF), WHICH PLAY A CENTRAL ROLE IN PLASTICITY. AS BDNF IS REPRESSED BY STRESS, EPIGENETIC REGULATION OF THE BDNF GENE MAY PLAY AN IMPORTANT ROLE IN DEPRESSION. THE HIPPOCAMPUS IS SMALLER IN DEPRESSED PATIENTS, ALTHOUGH IT IS UNCLEAR WHETHER SMALLER SIZE IS A CONSEQUENCE OF DEPRESSION OR A PRE-EXISTING, VULNERABILITY MARKER FOR DEPRESSION. ENVIRONMENTAL STRESSORS TRIGGERING ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS CAUSE THE BRAIN TO BE EXPOSED TO CORTICOSTEROIDS, AFFECTING NEUROBEHAVIOURAL FUNCTIONS WITH A STRONG DOWNREGULATION OF HIPPOCAMPAL NEUROGENESIS, AND ARE A MAJOR RISK FACTOR FOR DEPRESSION. ANTIDEPRESSANT TREATMENT INCREASES BDNF LEVELS, STIMULATES NEUROGENESIS AND REVERSES THE INHIBITORY EFFECTS OF STRESS, BUT THIS EFFECT IS EVIDENT ONLY AFTER 3-4 WEEKS OF ADMINISTRATION, THE TIME COURSE FOR MATURATION OF NEW NEURONS. THE ABLATION OF HIPPOCAMPAL NEUROGENESIS BLOCKS THE BEHAVIOURAL EFFECTS OF ANTIDEPRESSANTS IN ANIMAL MODELS. THE ABOVE FINDINGS SUGGEST NEW POSSIBLE TARGETS FOR THE PHARMACOTHERAPY OF DEPRESSION SUCH AS NEUROTROPHIC FACTORS, THEIR RECEPTORS AND RELATED INTRACELLULAR SIGNALLING CASCADES; AGENTS COUNTERACTING THE EFFECTS OF STRESS ON HIPPOCAMPAL NEUROGENESIS (INCLUDING ANTAGONISTS OF CORTICOSTEROIDS, INFLAMMATORY CYTOKINES AND THEIR RECEPTORS); AND AGENTS FACILITATING THE ACTIVATION OF GENE EXPRESSION AND INCREASING THE TRANSCRIPTION OF NEUROTROPHINS IN THE BRAIN. 2011 16 6627 38 UNDERSTANDING RESILIENCE: NEW APPROACHES FOR PREVENTING AND TREATING PTSD. ALL INDIVIDUALS EXPERIENCE STRESSFUL LIFE EVENTS, AND UP TO 84% OF THE GENERAL POPULATION WILL EXPERIENCE AT LEAST ONE POTENTIALLY TRAUMATIC EVENT. IN SOME CASES, ACUTE OR CHRONIC STRESSORS LEAD TO THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD) OR OTHER PSYCHOPATHOLOGY; HOWEVER, THE MAJORITY OF PEOPLE ARE RESILIENT TO SUCH EFFECTS. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. A WEALTH OF RESEARCH HAS BEGUN TO IDENTIFY THE GENETIC, EPIGENETIC, NEURAL, AND ENVIRONMENTAL UNDERPINNINGS OF RESILIENCE, AND HAS INDICATED THAT RESILIENCE IS MEDIATED BY ADAPTIVE CHANGES ENCOMPASSING SEVERAL ENVIRONMENTAL FACTORS, NEURAL CIRCUITS, NUMEROUS NEUROTRANSMITTERS, AND MOLECULAR PATHWAYS. THE FIRST PART OF THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING THE GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS AS WELL AS NEURAL CIRCUITS AND MOLECULAR PATHWAYS THAT UNDERLIE THE DEVELOPMENT OF RESILIENCE. EMERGING AND EXCITING AREAS OF RESEARCH AND NOVEL METHODOLOGICAL APPROACHES, INCLUDING GENOME-WIDE GENE EXPRESSION STUDIES, IMMUNE, ENDOCANNABINOID, OXYTOCIN, AND GLUTAMATERGIC SYSTEMS, ARE EXPLORED TO HELP DELINEATE INNOVATIVE MECHANISMS THAT MAY CONTRIBUTE TO RESILIENCE. THE SECOND PART REVIEWS SEVERAL INTERVENTIONS AND PREVENTATIVE APPROACHES DESIGNED TO ENHANCE RESILIENCE IN BOTH DEVELOPMENTAL AND ADULT POPULATIONS. SPECIFICALLY, THE REVIEW WILL DELINEATE APPROACHES AIMED TO BOLSTER RESILIENCE IN INDIVIDUALS WITH PTSD. FURTHERMORE, WE DISCUSS NOVEL PHARMACOLOGIC APPROACHES, INCLUDING THE N-METHYL-D-ASPARTATE (NMDA) RECEPTOR KETAMINE AND NEUROPEPTIDE Y (NPY), AS EXCITING NEW PROSPECTS FOR NOT ONLY THE TREATMENT OF PTSD BUT AS NEW TARGETS TO ENHANCE RESILIENCE. OUR GROWING UNDERSTANDING OF RESILIENCE AND INTERVENTIONS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW STRATEGIES FOR NOT JUST TREATING PTSD BUT ALSO SCREENING AND EARLY IDENTIFICATION OF AT-RISK YOUTH AND ADULTS. TAKEN TOGETHER, EFFORTS AIMED AT DISSEMINATION AND IMPLEMENTATION OF NOVEL INTERVENTIONS TO ENHANCE RESILIENCE WILL HAVE TO KEEP PACE WITH THE GROWTH OF NEW PREVENTIVE AND TREATMENT STRATEGIES. 2016 17 3961 33 LONG NON-CODING RNAS: THE NEW FRONTIER INTO UNDERSTANDING THE ETIOLOGY OF ALCOHOL USE DISORDER. ALCOHOL USE DISORDER (AUD) IS A COMPLEX, CHRONIC, DEBILITATING CONDITION IMPACTING MILLIONS WORLDWIDE. GENETIC, ENVIRONMENTAL, AND EPIGENETIC FACTORS ARE KNOWN TO CONTRIBUTE TO THE DEVELOPMENT OF AUD. LONG NON-CODING RNAS (LNCRNAS) ARE A CLASS OF REGULATORY RNAS, COMMONLY REFERRED TO AS THE "DARK MATTER" OF THE GENOME, WITH LITTLE TO NO PROTEIN-CODING POTENTIAL. LNCRNAS HAVE BEEN IMPLICATED IN NUMEROUS PROCESSES CRITICAL FOR CELL SURVIVAL, SUGGESTING THAT THEY PLAY IMPORTANT FUNCTIONAL ROLES IN REGULATING DIFFERENT CELL PROCESSES. LNCRNAS WERE ALSO SHOWN TO DISPLAY HIGHER TISSUE SPECIFICITY THAN PROTEIN-CODING GENES AND HAVE A HIGHER ABUNDANCE IN THE BRAIN AND CENTRAL NERVOUS SYSTEM, DEMONSTRATING A POSSIBLE ROLE IN THE ETIOLOGY OF PSYCHIATRIC DISORDERS. INDEED, GENETIC (E.G., GENOME-WIDE ASSOCIATION STUDIES (GWAS)), MOLECULAR (E.G., EXPRESSION QUANTITATIVE TRAIT LOCI (EQTL)) AND EPIGENETIC STUDIES FROM POSTMORTEM BRAIN TISSUES HAVE IDENTIFIED A GROWING LIST OF LNCRNAS ASSOCIATED WITH NEUROPSYCHIATRIC AND SUBSTANCE USE DISORDERS. GIVEN THAT THE EXPRESSION PATTERNS OF LNCRNAS HAVE BEEN ASSOCIATED WITH WIDESPREAD CHANGES IN THE TRANSCRIPTOME, INCLUDING METHYLATION, CHROMATIN ARCHITECTURE, AND ACTIVATION OR SUPPRESSION OF TRANSLATIONAL ACTIVITY, THE REGULATORY NATURE OF LNCRNAS MAY BE UBIQUITOUS AND AN INNATE COMPONENT OF GENE REGULATION. IN THIS REVIEW, WE PRESENT A SYNOPSIS OF THE FUNCTIONAL IMPACT THAT LNCRNAS MAY PLAY IN THE ETIOLOGY OF AUD. WE ALSO DISCUSS THE CLASSIFICATIONS OF LNCRNAS, THEIR KNOWN FUNCTIONAL ROLES, AND THERAPEUTIC ADVANCEMENTS IN THE FIELD OF LNCRNAS TO FURTHER CLARIFY THE FUNCTIONAL RELATIONSHIP BETWEEN LNCRNAS AND AUD. 2022 18 2415 27 EPIGENETIC SIGNALING IN PSYCHIATRIC DISORDERS: STRESS AND DEPRESSION. PSYCHIATRIC DISORDERS ARE COMPLEX MULTIFACTORIAL DISORDERS INVOLVING CHRONIC ALTERATIONS IN NEURAL CIRCUIT STRUCTURE AND FUNCTION. WHILE GENETIC FACTORS PLAY A ROLE IN THE ETIOLOGY OF DISORDERS SUCH AS DEPRESSION, ADDICTION, AND SCHIZOPHRENIA, RELATIVELY HIGH RATES OF DISCORDANCE AMONG IDENTICAL TWINS CLEARLY POINT TO THE IMPORTANCE OF ADDITIONAL FACTORS. ENVIRONMENTAL FACTORS, SUCH AS STRESS, PLAY A MAJOR ROLE IN THE PSYCHIATRIC DISORDERS BY INDUCING STABLE CHANGES IN GENE EXPRESSION, NEURAL CIRCUIT FUNCTION, AND ULTIMATELY BEHAVIOR. INSULTS AT THE DEVELOPMENTAL STAGE AND IN ADULTHOOD APPEAR TO INDUCE DISTINCT MALADAPTATIONS. INCREASING EVIDENCE INDICATES THAT THESE SUSTAINED ABNORMALITIES ARE MAINTAINED BY EPIGENETIC MODIFICATIONS IN SPECIFIC BRAIN REGIONS. INDEED, TRANSCRIPTIONAL DYSREGULATION AND ASSOCIATED ABERRANT EPIGENETIC REGULATION IS A UNIFYING THEME IN PSYCHIATRIC DISORDERS. ASPECTS OF DEPRESSION CAN BE MODELED IN ANIMALS BY INDUCING DISEASE-LIKE STATES THROUGH ENVIRONMENTAL MANIPULATIONS, AND THESE STUDIES CAN PROVIDE A MORE GENERAL UNDERSTANDING OF EPIGENETIC MECHANISMS IN PSYCHIATRIC DISORDERS. UNDERSTANDING HOW ENVIRONMENTAL FACTORS RECRUIT THE EPIGENETIC MACHINERY IN ANIMAL MODELS IS PROVIDING NEW INSIGHTS INTO DISEASE MECHANISMS IN HUMANS. 2014 19 6626 29 UNDERSTANDING RESILIENCE. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. STRESSFUL LIFE EVENTS, TRAUMA, AND CHRONIC ADVERSITY CAN HAVE A SUBSTANTIAL IMPACT ON BRAIN FUNCTION AND STRUCTURE, AND CAN RESULT IN THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD), DEPRESSION AND OTHER PSYCHIATRIC DISORDERS. HOWEVER, MOST INDIVIDUALS DO NOT DEVELOP SUCH ILLNESSES AFTER EXPERIENCING STRESSFUL LIFE EVENTS, AND ARE THUS THOUGHT TO BE RESILIENT. RESILIENCE AS SUCCESSFUL ADAPTATION RELIES ON EFFECTIVE RESPONSES TO ENVIRONMENTAL CHALLENGES AND ULTIMATE RESISTANCE TO THE DELETERIOUS EFFECTS OF STRESS, THEREFORE A GREATER UNDERSTANDING OF THE FACTORS THAT PROMOTE SUCH EFFECTS IS OF GREAT RELEVANCE. THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS THAT ARE CONSIDERED ESSENTIAL CONTRIBUTORS TO THE DEVELOPMENT OF RESILIENCE. NEURAL CIRCUITS AND PATHWAYS INVOLVED IN MEDIATING RESILIENCE ARE ALSO DISCUSSED. THE GROWING UNDERSTANDING OF RESILIENCE FACTORS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW PHARMACOLOGICAL AND PSYCHOLOGICAL INTERVENTIONS FOR ENHANCING RESILIENCE AND MITIGATING THE UNTOWARD CONSEQUENCES. 2013 20 2526 29 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