Mood disorder
A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where the main underlying characteristic is a disturbance in the person's mood. The classification is in the Diagnostic and Statistical Manual of Mental Disorders and International Classification of Diseases.
Mood disorders fall into seven groups, including: 1. abnormally elevated mood, such as mania or hypomania; 2. depressed mood, of which the best-known and most researched is major depressive disorder ; and 3. moods which cycle between mania and depression, known as bipolar disorder . 4. There are several subtypes of depressive disorders or psychiatric syndromes featuring less severe symptoms such as dysthymic disorder and cyclothymic disorder.
In some cases, more than one mood disorder can be present in an individual, like bipolar disorder and depressive disorder. Mood disorders may also be substance induced, or occur in response to a medical condition.
English psychiatrist Henry Maudsley proposed an overarching category of affective disorder. The term was then replaced by mood disorder, as the latter refers to the underlying or longitudinal emotional state, whereas the former refers to the external expression observed by others.
Classification
Depressive disorders
- Major depressive disorder, commonly called major depression, unipolar depression, or clinical depression, wherein a person has one or more major depressive episodes. After a single episode, Major Depressive Disorder would be diagnosed. After more than one episode, the diagnosis becomes Major Depressive Disorder. Depression without periods of mania is sometimes referred to as unipolar depression because the mood remains at the bottom "pole" and does not climb to the higher, manic "pole" as in bipolar disorder.
- Depressive disorder is frequent in primary care and general hospital practice but is often undetected. Unrecognized depressive disorder may slow recovery and worsen prognosis in physical illness, therefore it is important that all doctors be able to recognize the condition, treat the less severe cases, and identify those requiring specialist care.
Bipolar disorders
- Bipolar disorder , an unstable emotional condition characterized by cycles of abnormal, persistent high mood and low mood, which was formerly known as "manic depression". Subtypes include:
Substance-induced
Alcohol-induced
High rates of major depressive disorder occur in heavy drinkers and those with alcoholism. Controversy has previously surrounded whether those who abused alcohol and developed depression were self-medicating their pre-existing depression. Recent research has concluded that, while this may be true in some cases, alcohol misuse directly causes the development of depression in a significant number of heavy drinkers. Participants studied were also assessed during stressful events in their lives and measured on a Feeling Bad Scale. Likewise, they were also assessed on their affiliation with deviant peers, unemployment, and their partner's substance use and criminal offending. High rates of suicide also occur in those who have alcohol-related problems. It is usually possible to differentiate between alcohol-related depression and depression that is not related to alcohol intake by taking a careful history of the patient. Depression and other mental health problems associated with alcohol misuse may be due to distortion of brain chemistry, as they tend to improve on their own after a period of abstinence.Benzodiazepine-induced
s, such as alprazolam, clonazepam, lorazepam and diazepam, can cause both depression and mania.Benzodiazepines are a class of medication commonly used to treat anxiety, panic attacks and insomnia, and are also commonly misused and abused. Those with anxiety, panic and sleep problems commonly have negative emotions and thoughts, depression, suicidal ideations, and often have comorbid depressive disorders. While the anxiolytic and hypnotic effects of benzodiazepines may disappear as tolerance develops, depression and impulsivity with high suicidal risk commonly persist. These symptoms are "often interpreted as an exacerbation or as a natural evolution of previous disorders and the chronic use of sedatives is overlooked". Benzodiazepines do not prevent the development of depression, can exacerbate preexisting depression, can cause depression in those with no history of it, and can lead to suicide attempts. Risk factors for suicide and suicide attempts while using benzodiazepines include high dose prescriptions, benzodiazepine intoxication, and underlying depression.
The long-term use of benzodiazepines may have a similar effect on the brain as alcohol, and are also implicated in depression. As with alcohol, the effects of benzodiazepine on neurochemistry, such as decreased levels of serotonin and norepinephrine, are believed to be responsible for the increased depression. Additionally, benzodiazepines can indirectly worsen mood by worsening sleep. Like alcohol, benzodiazepines can put people to sleep but, while asleep, they disrupt sleep architecture: decreasing sleep time, delaying time to REM sleep, and decreasing deep sleep. Just as some antidepressants can cause or worsen anxiety in some patients due to being activating, benzodiazepines can cause or worsen depression due to being a central nervous system depressant—worsening thinking, concentration and problem solving. However, unlike antidepressants, in which the activating effects usually improve with continued treatment, benzodiazepine-induced depression is unlikely to improve until after stopping the medication.
In a long-term follow-up study of patients dependent on benzodiazepines, it was found that 10 people had taken drug overdoses while on chronic benzodiazepine medication despite only two people ever having had any pre-existing depressive disorder. A year after a gradual withdrawal program, no patients had taken any further overdoses.
Just as with intoxication and chronic use, benzodiazepine withdrawal can also cause depression. While benzodiazepine-induced depressive disorder may be exacerbated immediately after discontinuation of benzodiazepines, evidence suggests that mood significantly improves after the acute withdrawal period to levels better than during use. Depression resulting from withdrawal from benzodiazepines usually subsides after a few months but in some cases may persist for 6–12 months.
Due to another medical condition
"Mood disorder due to a general medical condition" is used to describe manic or depressive episodes which occur secondary to a medical condition. There are many medical conditions that can trigger mood episodes, including neurological disorders, hearing loss and associated disorders, metabolic disorders, gastrointestinal diseases, endocrine disease, cardiovascular disease, pulmonary disease, cancer, autoimmune diseases, and pregnancy.Not otherwise specified
Mood disorder not otherwise specified is a mood disorder that is impairing but does not fit in with any of the other officially specified diagnoses. In the DSM-IV MD-NOS is described as "any mood disorder that does not meet the criteria for a specific disorder." MD-NOS is not used as a clinical description but as a statistical concept for filing purposes. The diagnosis of MD-NOS does not exist in the DSM-5, however the diagnoses of unspecified depressive disorder and unspecified bipolar disorder are in the DSM-5.Most cases of MD-NOS represent hybrids between mood and anxiety disorders, such as mixed anxiety-depressive disorder or atypical depression. An example of an instance of MD-NOS is being in minor depression frequently during various intervals, such as once every month or once in three days. There is a risk for MD-NOS not to get noticed, and for that reason not to get treated.
Causes
Meta-analyses show that high scores on the personality domain neuroticism are a strong predictor for the development of mood disorders.A depressed mood is a predictable response to certain types of life occurrences, such as loss of status, divorce, or death of a child or spouse. These are events that signal a loss of reproductive ability or potential, or that did so in humans' ancestral environment. A depressed mood can be seen as an adaptive response, in the sense that it causes an individual to turn away from the earlier modes of behavior.
A depressed mood is common during illnesses, such as influenza. It has been argued that this is an evolved mechanism that assists the individual in recovering by limiting their physical activity. The occurrence of low-level depression during the winter months, or seasonal affective disorder, may have been adaptive in the past, by limiting physical activity at times when food was scarce. It is argued that humans have retained the instinct to experience low mood during the winter months, even if the availability of food is no longer determined by the weather.
Much of what is known about the genetic influence of clinical depression is based upon research that has been done with identical twins. Identical twins have exactly the same genetic code. It has been found that when one identical twin becomes depressed the other will also develop clinical depression approximately 76% of the time. When identical twins are raised apart from each other, they will both become depressed about 67% of the time. Because both twins become depressed at such a high rate, the implication is that there is a strong genetic influence. If it happened that when one twin becomes clinically depressed the other always develops depression, then clinical depression would likely be entirely genetic.
Bipolar disorder is also considered a mood disorder and it is hypothesized that it might be caused by mitochondrial dysfunction.