Mood disorders involve serious changes in mood that disrupt typical life activities. Many different subtypes have been identified. The most common illnesses categorized as mood disorders include major depressive disorder, bipolar disorder, dysthymia (persistent depressive disorder), substance-induced mood disorder, and seasonal affective disorder (SAD).
More than 21% of US adults experience a mood disorder at some point during their lives. Worldwide, more than 300 million people are affected by depression and other mood disorders. These conditions have been associated with an increased risk for suicide and for such health issues as diabetes and heart disease, among others.
Are you familiar with key aspects and best practices for various forms of mood disorder? Test your knowledge with this short quiz.
According to DSM-5 criteria for major depressive disorder, at least five of the following symptoms must be present during the same 2-week period (and at least one of the symptoms must be diminished interest/pleasure or depressed mood):
- Depressed mood: For children and adolescents, this can also be an irritable mood
- Diminished interest or loss of pleasure in almost all activities (anhedonia)
- Significant weight change or appetite disturbance: For children, this can be failure to achieve expected weight gain
- Sleep disturbance (insomnia or hypersomnia)
- Psychomotor agitation or retardation
- Fatigue or loss of energy
- Feelings of worthlessness
- Diminished ability to think or concentrate; indecisiveness
- Recurrent thoughts of death, recurrent suicidal ideation without a specific plan, or a suicide attempt or specific plan for committing suicide
The symptoms must cause significant distress or impairment in social, occupational, or other important areas of functioning. The key is impairment. Many individuals have moments of depression; however, in mood disorder, patients cannot function vocationally or socially.
The symptoms must not be attributable to the physiologic effects of a substance (eg, a drug of abuse, a medication) or another medical condition. For example, patients with hypothyroidism may demonstrate the above symptoms. However, once the thyroid condition has been treated, the patient returns to normal functioning.
The disturbance must not be better explained by a persistent schizoaffective disorder, schizophrenia, delusional disorder, or other specified or unspecified schizophrenia spectrum and other psychotic disorders. The patient must not have a history of a manic episode or hypomanic episode.
Depressive disorders can be rated as mild, moderate, or severe. The disorder can also occur with psychotic symptoms, which can be mood congruent or incongruent. Depressive disorders can be determined to be in full or partial remission.
The DSM-5 further notes the importance of distinguishing between normal sadness and grief from a major depressive disorder. Although bereavement can induce great suffering, it does not typically induce a major depressive disorder. When the two are simultaneously present, the symptoms and functional impairment are more severe, and the prognosis is worse compared with bereavement alone. A diagnosis of major depressive disorder after a significant loss requires clinical judgment based on the individual's history and the cultural context for expression of grief.
Read more about major depressive disorder.
Interferon alpha significantly increased the incidence of depression in randomized controlled trials and prospective cohort studies. Although only one of the trials was designed to study this as an endpoint and none of the trials uses standardized interviews for psychiatric assessments, the relatively high proportion of depression in this population (20%-45%) raises important questions about interferon tolerability and toxicity. Patients with hepatitis C and a history of psychiatric illness (and, more specifically, depression) before interferon-alpha treatment are at an even a higher risk for interferon-induced depression.
Different types of interferon may have different risk profiles. In a prospective study of 96 patients treated with different types of interferon, the highest incidence of depression was reported with interferon alpha-n1, the lowest incidence with interferon alpha-n3, and the most severe depression and the highest rate of suicidal ideation with interferon alpha-2b.
The use of metformin has been associated with antidepressant effects. Lamotrigine and topiramate are anticonvulsants that have demonstrated use as mood stabilizers.
Read more about substance-induced mood disorder.
In the DSM-5, persistent depressive disorder (dysthymia) is a depressive mood disorder characterized by a chronic course and an early, insidious onset (ie, in childhood, adolescence, or early adulthood). Early onset (ie, before age 21 years) is associated with higher risk for comorbid personality disorders and substance use disorders.
Although dysthymia has been traditionally considered less severe than major depressive disorder, the consequences of dysthymia are increasingly recognized as grave; they include severe functional impairment, increased morbidity from physical disease, and increased risk for suicide.
Compared with major depression, patients with dysthymia tend to have more subjective symptoms, with fewer dramatic psychomotor disturbances or neurovegetative symptoms, such as abnormal sleep, appetite, and libido. In other words, these patients do not exhibit the severe, debilitating symptoms associated with major depression.
Some patients report a diurnal variation, with low energy, inertia, and anhedonia that is worse in the morning. People with dysthymia may exhibit decreased mental flexibility on neuropsychological testing.
To summarize, the most common symptoms include the following:
- A negative, pessimistic, or gloomy outlook
- Depressed mood
- Restlessness
- Anxiety
- Neurovegetative symptoms: disturbed sleeping and feeding behaviors, lethargy; usually less marked than those seen in a major depressive episode
- Loss of pleasurable feelings (anhedonia)
- Tendency to spend little time engaged in leisure activities
- Tendency to anticipate that future events and future affective experiences will be negative
The Third National Health and Nutrition Examination Survey (NHANES III) found that dysthymia is more common among African Americans and Mexican Americans than among white Americans.
Although still unclear, the cause of dysthymia is probably multifactorial. Common contributing factors include the following:
- Genetic predisposition
- Biological factors, such as alterations in neurotransmitters, endocrine, or inflammatory mediators
- Chronic stress, particularly with feelings of hopelessness or helplessness
- Chronic medical illness
- Psychosocial factors, such as social isolation, losses, or poverty
- Ruminative coping strategies: As opposed to problem-solving or cognitive restructuring strategies, these are common among people with dysthymia and may predispose to or sustain dysthymia
- Antisocial, borderline, dependent, depressive, histrionic, or schizotypal personality traits: People diagnosed with these are at an increased risk for developing dysthymic disorder
Dysthymia is more of a persistent condition rather than an acute illness. It can be the result of ongoing physical problems and negative environmental situations. Patients with dysthymia often have a less than optimistic view of life.
According to the latest guidelines on bipolar disorder from the British Psychological Society and Royal College of Psychiatrists, questionnaires should not be used in primary care to identify bipolar disorder in adults. When diagnosing bipolar disorder in children or young people, mania must be present; euphoria must be present on most days and for most of the time, for at least 7 days; and irritability is not a core diagnostic criterion.
Among other recommendations for treatment, the guidelines state that if a patient develops moderate or severe bipolar depression and is not receiving a drug to treat their bipolar disorder, fluoxetine combined with olanzapine, or quetiapine on its own, should be offered, depending on the patient's preference and previous response to treatment. If the patient prefers, consider either olanzapine (without fluoxetine) or lamotrigine on its own. If the patient has no response to fluoxetine combined with olanzapine, or quetiapine monotherapy, consider lamotrigine on its own.
In addition, the guidelines recommend offering lithium as a first-line, long-term pharmacologic treatment for bipolar disorder and, if lithium is ineffective, consider adding valproate; if lithium is poorly tolerated, or is not suitable (eg, because the patient does not agree to routine blood monitoring), consider valproate or olanzapine instead or, if it has been effective during an episode of mania or bipolar depression, quetiapine. Measure plasma lithium levels 1 week after starting lithium and 1 week after every dose change, and weekly until the levels are stable. Aim to maintain the plasma lithium level between 0.6 and 0.8 mmol/L in patients who are prescribed lithium for the first time.
Classified as a mood stabilizer, lithium is one of the first drugs that has a preventive aspect and potential. It serves both to prevent the highs (manic phase) and the lows (major depression phase) of bipolar disorder. When taken as prescribed and if the proper lithium levels are maintained, many patients with bipolar disorder have fewer psychiatric hospitalizations.
Read more about the treatment of bipolar disorder.
According to the American Psychiatric Association, BLT, talk therapy, antidepressant medications or some combination may be indicated for patients with SAD. Some people may begin BLT in early fall to prevent symptoms. Some patients with SAD who live in the northern hemisphere relocate in the fall to places with longer hours of daylight to prevent or lessen their winter depression.
Although no data suggest that BLT is associated with retinal or ocular damage, ophthalmologic examinations before initiation of BLT and at regular follow-up visits are recommended for patients with preexisting retinal disease, those taking photosensitizing medications, and those with systemic diseases that involve the retina. Patients often respond to BLT in as little as 1-2 weeks. Typically, BLT is continued until the time of their usual spring remission.
BLT for SAD is used at an intensity of 10,000 lux for 30-90 minutes daily, usually within 1 hour of arising in the morning. Like any effective antidepressant, BLT has the potential to precipitate a hypomanic or manic episode in susceptible individuals. Other common adverse effects include eye irritation, restlessness, and transient headaches. These lamps are not a significant source of UV light.
Read more about the treatment of SAD.
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