Dysthymic disorder is defined as a mood disorder with chronic (long-term) depressive symptoms that are present most of the day, more days than not, for a period of at least two years.
Everyone experiences feelings of unhappiness and sadness occasionally. When these depressed feelings start to dominate everyday life and cause physical and mental deterioration, the feelings become known as depressive disorders. Depressive disorders can be categorized as major depressive disorder or dysthymic disorder. Individuals who suffer from dysthymic disorder have had their depressive symptoms for years— they often cannot pinpoint exactly when they started to feel depressed. People suffering from dysthymic disorder may describe to their doctor feelings of hopelessness, lowered self-esteem, poor concentration, indecisiveness, decreased motivation, sleeping too much or too little, or eating too much or too little. Symptoms are present often and for the whole day, and are typically present for at least two years.
Causes and symptoms
The causes of depression are complex and not yet completely understood. Sleep abnormalities, hormones, neurotransmitters (chemicals that communicate impulses from one nerve cell to another), upbringing, heredity, and stressors (significant life changes or events that cause stress ) all have been implicated as causes of depression.
Dysthymic disorder occurs in approximately 25% to 50% of persons who have sleep abnormalities that include reduced rapid eye movement (REM) sleep and impaired sleep continuity. Rapid eye movement sleep is an essential component of the sleep cycle and quality of sleep.
There is some evidence that suggests a correlation with hormonal imbalances of cortisol or thyroid hormones. In many adults, levels of cortisol (a stress hormone) are elevated during acute depressive periods and return to normal when the person is no longer depressed. In children and adolescents, results have been quite inconsistent, although there is some evidence that hypersecretion of cortisol is associated with more severe depressive symptoms and with a higher likelihood of recurrence of depression. A lack of thyroid hormone mimics depression quite well and is routinely checked in patients with recent onset depression.
In depression, there appears to be abnormal excess or inhibition of signals that control mood, thoughts, pain, and other sensations. Some studies suggest an imbalance of the neurotransmitter called serotonin. It is assumed that the reason antidepressants are effective is that they correct these chemical imbalances. For example, the selective serotonin reuptake inhibitors (SSRIs), one class of antidepressant medications that includes fluoxetine (Prozac), appears to establish a normal level of serotonin. As the name implies, the drug inhibits the re-uptake of serotonin neurotransmitter from the gaps between the nerve cells, thus increasing neurotransmitter action, alleviating depressive symptoms.
A child's upbringing may also be key in the development of dysthymic disorder. For example, it is speculated that if a person is abused and neglected throughout childhood and adolescence, a pattern of low self-esteem and negative thinking may emerge, and, from that, a lifelong pattern of depression may follow.
Heredity seems to play a role in the development of depressive disorders. People with major depression in their immediate family are up to three times more likely to have the disorder themselves. It would seem that biological and genetic factors may make certain individuals more prone to depressive disorders, but that environmental circumstances, or stressors, may then trigger the disorder.
The mental health professional's handbook to aid patient diagnosis is the Diagnostic and Statistical Manual of Mental Disorders, also called the DSM. The 2000 edition of this manual is known as the DSM-IV-TR (fourth edition, text revised). The DSM-IV-TR has established a list of criteria that can indicate a diagnosis. These criteria include:
- Depressed mood for most of the day, more days than not.
- When depressed, two (or more) of the following are also present: decreased appetite or overeating, too much or too little sleep, low energy level, low self-esteem, decreased ability to concentrate, difficulty making decisions, and/ or feelings of hopelessness.
- During the two years of the disorder, the patient has never been without symptoms listed for more than two months at a time.
- No major depressive episode (a more severe form of depression) has been present during the first two years of the disorder.
- There has never been a manic disorder, and criteria for a less severe depression called cyclothymic disorder has never been established.
- The disorder does not exclusively occur with psychosis , schizophrenia or delusional illnesses.
- The symptoms of depression cause clinically significant impairment and distress in occupational, social, and general functioning. Dysthymic disorder can be described as "early onset" (onset before age 21 years), "late onset" (onset is age 21 years or older), and "with atypical features" (features that are not commonly observed).
The lifetime prevalence has been estimated to be 4.1% for women and 2.2% for men. In adults, dysthymic disorder is more common in women than in men and research suggests that the prevalence in the age group 25 to 64 years is 6% for women. In children, dysthymic disorder can occur equally among both genders.
To diagnose a patient with this disorder, the DSM-IVTR criteria must be established, and this is accomplished through an extensive psychological interview and evaluation. The affected person seeking the clinician's help usually exhibits symptoms of irritability, feelings of worthlessness and hopelessness, crying spells, decreased sex drive, agitation, and thoughts of death. The clinician must rule out any possible medical conditions that can cause depressed affect . (Affect can be defined as the expression of emotion displayed to others through facial expressions, hand gestures, tone of voice, etc.) The diagnosis cannot be made if depression occurs during an active course of psychosis, delusions , schizophrenia, or schizoaffective disorder . If substance abuse is determined as the cause of depression, then a diagnosis of substance-induced mood disorder can be established.
Further psychological tests that can be administered to help in the diagnostic process include the Beck Depression Inventory and the Hamilton Depression Scale .
The goals of treatment include remission of symptoms and psychological and social recovery.
Studies suggest some treatment success with medications such as tricyclic antidepressants (TCAs) or monoaminoxidase inhibitors (MAOIs). Medications can be effective in patients who have depression due to sleep abnormalities. Some tricyclic antidepressants include amitriptyline (Elavil), imipramine (Tofranil), and nortriptyline (Aventyl, Pamelor), and some MAOIs include tranylcypromine (Parnate) and phenelzine (Nardil). Selective serotonin reuptake inhibitors (SSRIs) are recommended during initial treatment planning after a definitive diagnosis is well established. The most commonly prescribed SSRIs are fluoxetine (Prozac), sertraline (Zoloft), paroxetine (Paxil), fluvoxamine (Luvox), and citalopram (Celexa).
Clinical reports suggest that cognitive-behavioral therapy , interpersonal psychotherapy , or family therapy can be effective with concurrent antidepressant medication to treat the symptoms of depression. In these therapies, the goal is to help the patient develop healthy problem-solving and coping skills.
Dysthymic disorder often begins in late childhood or adolescence. The disorder follows a chronic (long-term) course. The development of a more major form of clinical depression called major depressive disorder among children with dysthymic disorder is significant. In other words, childhood onset of dysthymic disorder is considered an early indicator for recurrent mood disorder that may even have more severe clinical symptoms in the patient's future.
Patients with this disorder usually have impaired emotional, social, and physical functioning.
In general, the clinical course of dysthymic disorder is not promising. Causes of a poorer outcome include not completing treatment, noncompliance with medication intake, and lack of willingness to change behaviors that promote a depressed state. However, patients can do very well with a short course of medications if they have a desire to follow psychotherapy treatment recommendations.
If left untreated, dysthymic disorder can result in significant financial and occupational losses. People with this disorder tend to isolate themselves by restricting daily activities and spending days in bed. Patients often complain of poor health and incur more disability days when compared to the general population. Higher rates of successful outcome occur in people who undergo psychotherapy and treatment with appropriate medications.
There is no known prevention for dysthymic disorder. Early intervention for children with depression may be effective in arresting the development of more severe problems.
See also Neurotransmitters; Origin of mental illness
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Laith Farid Gulli, M.D. Linda Hesson, M.A., LLP, CAC
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