Bipolar disorder, previously known as manic depression, is a mental disorder characterized by periods of depression and periods of abnormally elevated mood that each last from days to weeks. If the elevated mood is severe or associated with psychosis, it is called mania; if it is less severe, it is called hypomania. During mania, an individual behaves or feels abnormally energetic, happy or irritable, and they often make impulsive decisions with little regard for the consequences. There is usually also a reduced need for sleep during manic phases. During periods of depression, the individual may experience crying and have a negative outlook on life and poor eye contact with others. The risk of suicide is high; over a period of 20 years, 6% of those with bipolar disorder died by suicide, while 30–40% engaged in self-harm. Other mental health issues, such as anxiety disorders and substance use disorders, are commonly associated with bipolar disorder.
Major depressive disorder (MDD), also known as clinical depression, is a mental disorder characterized by at least two weeks of pervasive low mood, low self-esteem, and loss of interest or pleasure in normally enjoyable activities. Introduced by a group of US clinicians in the mid-1970s, the term was adopted by the American Psychiatric Association for this symptom cluster under mood disorders in the 1980 version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III), and has become widely used since.
A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where a disturbance in the person's mood is the main underlying feature. The classification is in the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD).
Monoamine oxidase A, also known as MAO-A, is an enzyme that in humans is encoded by the MAOA gene. This gene is one of two neighboring gene family members that encode mitochondrial enzymes which catalyze the oxidative deamination of amines, such as dopamine, norepinephrine, and serotonin. A mutation of this gene results in Brunner syndrome. This gene has also been associated with a variety of other psychiatric disorders, including antisocial behavior. Alternatively spliced transcript variants encoding multiple isoforms have been observed.
l-Kynurenine is a metabolite of the amino acid l-tryptophan used in the production of niacin.
Scientific studies have found that different brain areas show altered activity in humans with major depressive disorder (MDD), and this has encouraged advocates of various theories that seek to identify a biochemical origin of the disease, as opposed to theories that emphasize psychological or situational causes. Factors spanning these causative groups include nutritional deficiencies in magnesium, vitamin D, and tryptophan with situational origin but biological impact. Several theories concerning the biologically based cause of depression have been suggested over the years, including theories revolving around monoamine neurotransmitters, neuroplasticity, neurogenesis, inflammation and the circadian rhythm. Physical illnesses, including hypothyroidism and mitochondrial disease, can also trigger depressive symptoms.
Michael J. Meaney, CM, CQ, FRSC, is a professor at McGill University specializing in biological psychiatry, neurology, and neurosurgery, who is primarily known for his research on stress, maternal care, and gene expression. His research team has "discovered the importance of maternal care in modifying the expression of genes that regulate behavioral and neuroendocrine responses to stress, as well as hippocampal synaptic development" in animal studies. The research has implications for domestic and public policy for maternal support and its role in human disease prevention and economic health.
Eric J. Nestler is the Nash Family Professor of Neuroscience, Director of the Friedman Brain Institute, and Dean for Academic Affairs at the Icahn School of Medicine at Mount Sinai and Chief Scientific Officer of the Mount Sinai Health System. His research is focused on a molecular approach to drug addiction and depression.
Behavioral epigenetics is the field of study examining the role of epigenetics in shaping animal and human behavior. It seeks to explain how nurture shapes nature, where nature refers to biological heredity and nurture refers to virtually everything that occurs during the life-span. Behavioral epigenetics attempts to provide a framework for understanding how the expression of genes is influenced by experiences and the environment to produce individual differences in behaviour, cognition, personality, and mental health.
Sociogenomics, also known as social genomics, is the field of research that examines why and how different social factors and processes affect the activity of the genome. Social genomics as a field is very young and was spurred by the scientific understanding that the expression of genes to their gene products, though not the DNA sequence itself, is affected by the external environment. Social genomics researchers have thus examined the role of social factors on the expression of individual genes, or more commonly, clusters of many genes.
Aticaprant, also known by its developmental codes JNJ-67953964, CERC-501, and LY-2456302, is a κ-opioid receptor (KOR) antagonist which is under development for the treatment of major depressive disorder. A regulatory application for approval of the medication is expected to be submitted by 2025. Aticaprant is taken by mouth.
The genetic influences of post-traumatic stress disorder are not understood well due to the limitations of any genetic study of mental illness; in that, it cannot be ethically induced in selected groups. Because of this, all studies must use naturally occurring groups with genetic similarities and differences, thus the amount of data is limited. However, genetics play some role in the development of PTSD. Approximately 30% of the variance in PTSD is caused by genetics alone. For twin pairs exposed to combat in Vietnam, having a monozygotic (identical) twin with PTSD was associated with an increased risk of the co-twin's having PTSD compared to twins that were dizygotic.
Epigenetics of depression is the study of how epigenetics contribute to depression.
Immuno-psychiatry, according to Pariante, is a discipline that studies the connection between the brain and the immune system. It differs from psychoneuroimmunology by postulating that behaviors and emotions are governed by peripheral immune mechanisms. Depression, for instance, is seen as malfunctioning of the immune system.
Transgenerational stress inheritance is the transmission of adverse effects of stress-exposure in parents to their offspring through epigenetic mechanisms.
Frances A. Champagne is a Canadian psychologist and University Professor of Psychology at the University of Texas at Austin known for her research in the fields of molecular neuroscience, maternal behavior, and epigenetics. Research in the Champagne lab explores the developmental plasticity that occurs in response to environmental experiences. She is known for her work on the epigenetic transmission of maternal behavior. Frances Champagne's research has revealed how natural variations in maternal behavior can shape the behavioral development of offspring through epigenetic changes in gene expression in a brain region specific manner. She won the NIH Director's New Innovator Award in 2007 and the Frank A. Beach Young Investigator Award in Behavioral Neuroendocrinology in 2009. She has been described as the "bee's knees of neuroscience". She serves on the Committee on Fostering Healthy Mental, Emotional, and Behavioral Development Among Children and Youth in the United States.
Epigenetics of anxiety and stress–related disorders is the field studying the relationship between epigenetic modifications of genes and anxiety and stress-related disorders, including mental health disorders such as generalized anxiety disorder (GAD), post-traumatic stress disorder, obsessive-compulsive disorder (OCD), and more.
Heather Clare Whalley is a Scottish scientist. She is a senior research fellow in Neuroimaging at the Centre for Clinical Brain Sciences, University of Edinburgh., and is an affiliate member of the Centre for Genomic and Experimental Medicine at the University of Edinburgh. Her main focus of research is on the mechanisms underlying the development of major psychiatric disorders using the latest genomic and neuroimaging approaches.
Andrew M. McIntosh is a UK academic psychiatrist. He is Professor of Biological Psychiatry at the Centre for Clinical Brain Sciences, University of Edinburgh, and is an affiliate member of the Centre for Genomic and Experimental Medicine at the University of Edinburgh. The main focus of his research is using genomic and neuroimaging approaches to better understand the causes and causal consequences of Major Depressive Disorder.
Epigenetics of bipolar disorder is the effect that epigenetics has on triggering and maintaining the bipolar disorder.
