User:Logan McAbee-Thomas/sandbox

Overview
Euthymia is defined as a normal, tranquil mental state or mood. It is often used to describe a stable mental state or mood in those affected with bipolar disorder that is neither manic nor depressive, yet is distinguishable from healthy controls. Euthymia is also used to describe the “baseline” of other cyclic mood disorders like Major depressive disorder (MDD) and Narcissistic personality disorder (NPD). The goal of many interventions for bipolar disorder is to bring the patient back to a state of euthymia.

History
Euthymia is typically defined by the absence of mood symptoms. When a person no longer meets the DSM-5 criterion for mania or depression, they are described as being in a euthymic state. The challenge that current research is faced with is working to create a positive and more comprehensive and detailed definition of euthymia. The word ‘euthymia’ traces its roots to the Greek words eu, meaning well, and “thymo”, meaning soul or emotion. The word “thymos” also had four additional meanings; life energy; feelings and passions; desires, and inclinations; and thought or intelligence. Euthymia is also derived from a verb, euthymeo, that meant both “I am happy, in good spirits” and “I make others happy, I reassure and encourage.” This is the basis on which the first formal definition of euthymia was built. Democritus said that the state of euthymia is when “one is satisfied with what is present and available, taking little heed of people who are envied and admired and observing the lives of those who suffer and yet endure”, This was later amended in the translation given to us by the Greek philosopher Seneca the Younger in which euthymia means a state of internal calm and contentment. Seneca was also the first to link the state of euthymia to a learning process; in order to achieve it, one must be aware of psychological well-being. Seneca’s definition also included a cache about detachment from current events. Later, the Greek biographer Plutarch removed this cache with his definition which focused more on learning from adverse events. In 1958, Marie Jodah gave a modern clinical definition of mental health in the terms of positive symptoms by outlining the criteria for mental health: "autonomy (regulation of behavior from within), environmental mastery, satisfactory interactions with other people and the milieu, the individual’s style and degree of growth, development or self-actualization, the attitudes of an individual toward his/her own self". In her definition she acknowledged the absence of disease as being necessary, but not enough, to constitute positive mental health, or euthymia.

Measurment
Carol Ryff (1989), was the first to develop a comprehensive scale that could assess euthymia- the Six-factor Model of Psychological Well-being. The 84-item scale includes facets of self-acceptance, positive relations with others autonomy, environmental mastery, purpose in life, and personal growth. This scale, however, failed to include Jodah’s concept of flexibility. In facets of personality inventories like the Revised NEO Personality Inventory(NEO-PI), the definition of euthymia is broadened to encompass all of positive feeling or “well-being”. This broader definition is usually held in contrast to dysthymia, or “ill-being”. Disagreement about these definitions arises because the euthymia and dysthymia “subscales” do not meet the threshold for scalability in a Mokken scale analysis. Common NEO-PI euthymia items include such questions as “I am seldom sad or depressed.”, “I am pretty stable emotionally.”, and “I rarely feel fearful or anxious.”

Criteria
If a person has a history of mood disorders, they must be in full remission of all symptoms to be considered in a state of euthymia. If any sadness, anxiety, or other negative moods do appear, then they should only last for a short time before returning to normal levels and they should not affect everyday living. People in a state of euthymia are often happy, cheerful, calm, active, and interested in doing things. They present a certain level of psychological flexibility, meaning they are able to adapt to new and changing situations. Additionally, they experience restful and restorative sleep. However, increased feelings of impulsivity and emotional dysregulation, which are often seen during mania, have been found to persist during euthymia.

Comparison to Healthy Controls
Euthymia is often thought to be the same as being healthy and/or "normal". However, there are several differences between healthy controls and patients in a state of euthymia. For example, a study done by Foland-Ross et. al. in 2012, compared 24 euthymic bipolar patients during euthymia, to a healthy control group. They found a significant decrease in activation of the right ventrolateral prefrontal cortex in the brains of euthymic patients during the process of emotional labeling, which is acknowledging and understanding an emotion based on physical and non-physical clues.

There is a lack of consensus among researchers as to whether or not there is a deficit in emotion recognition during any phase of euthymia. According to Folland-Ross et. al. in 2012, there is greater connectivity between the right amygdala and the right ventrolateral prefrontal cortex in patients during euthymia in comparison to healthy controls. Because of this, people in a state of euthymia may experience greater motor control reactions in response to negative emotion stimulation such as fear, sadness, and anger.

Physiologically, bipolar patients in euthymia differ from typical healthy individuals in their brain structure. Canales-Rodríguez (2014) found that people in euthymia have significant grey matter reductions in their splenium (part of the corpus callosum), and right and anterior part of the insula compared to healthy controls. There were also abnormalities in their anterior cingulate cortex regions, which play a role in heart rate regulation and blood pressure, and white matter found in the prefrontal cortex, which can affect cognitive behavior, personality expression, decision making, and social behavior. This may help explain why there are often cognitive deficits found in patients in euthymia when compared to healthy control groups. There are also often anomalies in the hippocampus, the parahippocampal gyrus, which are essential for memory, and the caudate nucleus, which is important for motor function, although anomalies in the caudate nucleus are only prevalent in psychotic bipolar patients.

Another difference between healthy individuals and those in a state of euthymia in the production of morning serum cortisol. Serum cortisol shuts off the inhibitors of adrenal cortisol, allowing the stress response hormone to flow more freely. A study by Johansson and Landén in 2011 compared a sample of 80 female and 52 male euthymic Bipolar 1 disorder patients, and 44 female and 25 male euthymic Bipolar II disorder, to 18 healthy controls and found no significant difference in morning serum cortisol production from healthy controls. However, in men, the euthymic Bipolar 1 patients were categorized as having higher morning serum cortisol levels than healthy individuals. Euthymic male patients with Bipolar II also show elevated levels of morning serum cortisol from that of healthy controls, while females do not show this elevation.

Comparison to other Bipolar states
During states of euthymia, there is decreased activation in the amygdala, insula, putamen, thalamus and lingual gyrus compared to patients in a manic state. According to Blumberg 2012, there is a stress component to the switch from euthymia to mania that has been observed and this may be due to the hypothalamic-pituitary-adrenal axis, which regulates the body’s stress response and many bodily functions including digestion, the immune system, mood, and energy use. In comparison to a state of depression, during euthymia there is a noticeably significant decrease in availability of Alpha-4 beta-2 nicotinic receptor] across the frontal, parietal, temporal, and anterior [[cingulate cortex, hippocampus, amygdala, thalamus, striatum. People in a state of euthymia have lower endogenous acetylcholine levels than during depression. The concentrations of interleukin 10, tumor necrosis factor alpha, neutrophil, and monocytes in the blood are all linked to proper immune system functioning and are altered in patients with bipolar disorder a during euthymic state. This means that someone in a euthymic state may experience the disease process differently than they would in a manic or depressive state.

Psychological Functioning
The degree to which those in a state of euthymia demonstrate a deficit in emotional processing relative to healthy controls continues to be an empirical debate. Some studies have found there is little to no deficit, while others have found there to be a significant difference. During euthymia, it has been found that the easiest emotion to recognize is happiness and that the most difficult to recognize is anger.

Sociological Functioning
During euthymia, there are often differences in the processing of other’s facial emotions, the interpreting of social cues, and feeling empathy. When processing the emotions of others, people in a state of euthymia experience higher amygdala, insula, and putamen activation than healthy people in response to negative facial expressions.

Personality
A patient’s impulsivity can affect the time that it takes for euthymia to be reached in bipolar disorder. Often, people that are more impulsive will experience a longer time before they are able to reach euthymia.