Depression is a word with many meanings - anything from a passing mood of sadness or discouragement to a condition of inconsolable misery, suicidal thoughts, and even delusions as well as severe physical symptoms. It's regarded as a clinical disorder when depressed mood and related symptoms are serious enough or last long enough to interfere with work, social life, family life, or physical health.
The Greek word dysthymia means "bad state of mind" or "ill humor." As one of the two chief forms of clinical depression, it usually has fewer or less serious symptoms than major depression but lasts longer. The American Psychiatric Association defines dysthymia as depressed mood most of the time for at least two years, along with at least two of the following symptoms: poor appetite or overeating; insomnia or excessive sleep; low energy or fatigue; low self-esteem; poor concentration or indecisiveness; and hopelessness.
Dysthymia and major depression naturally have many symptoms in common, including depressed mood, disturbed sleep, low energy, and poor concentration. There are also parallel symptoms: poor appetite, low self-esteem, and hopelessness in dysthymia, corresponding to the more severe symptoms of weight change, excessive guilt, and thoughts of death or suicide in major depression. Major depression may also include two symptoms not found in the standard definition of dysthymia: anhedonia (inability to feel pleasure) and psychomotor symptoms (chiefly lethargy or agitation). An episode of major depression requires at least five symptoms instead of three, but it need last only two weeks rather than two years.
Dysthymia is a serious disorder. It is not "minor" depression, and it is not a condition intermediate between severe clinical depression and depression in the casual colloquial sense. In some cases it is more disabling than major depression. Still, dysthymia is so similar to major depression that the American Psychiatric Association's diagnostic manual also suggests, as a possibility for further investigation, an alternative definition with symptoms including anhedonia, social withdrawal, guilt, and irritability but not appetite or sleep disturbance. The purpose is to distinguish dysthymia more clearly from major depression by emphasizing mood and personal relations over physical symptoms.
Dysthymia is about as common as major depression. Given its chronic nature, that makes it one of the disorders most often seen by psychotherapists. About 6% of the population of the United States has had an episode of dysthymia at some time, 3% in the last year. As many as a third of patients in psychotherapy may be suffering from dysthymia. Like major depression, it is more common in women than in men, but it tends to arise earlier in life. The American Psychiatric Association distinguishes between this early-onset form and a form that occurs later in life and often comes on less gradually.
More than half of people with dysthymia eventually have an episode of major depression, and about half of patients treated for major depression are suffering from this double depression. Many patients who recover partially from major depression also have milder symptoms that persist for years. This type of chronic depression is difficult to distinguish from dysthymia.
Is there a depressive personality?
In principle, personality is usually lifelong, while moods come and go. But dysthymia has to last longer than any other psychiatric disorder in the manual. That can make it difficult to distinguish from a personality disorder - especially the group that includes avoidant, dependent, and obsessive-compulsive personality, with their symptoms of timidity, excessive worry, helplessness, and social withdrawal.
Some would prefer to speak of a depressive personality disorder instead. That diagnosis was removed from the official manual in 1980 but has been re-introduced as a possible topic of investigation. The proposed symptoms include a strong tendency to be critical of oneself and others, pessimism, guilt, brooding, and gloominess. Anhedonia and physical symptoms are not part of the definition, but this personality disorder otherwise has a great deal in common with dysthymia.
Mood and personality are the emotional weather and emotional climate of individuals, so the symptoms of mood and personality disorders naturally overlap. The thought schemas that cognitive therapists find at the roots of major depression and dysthymia - certain beliefs about the self, the world, and the future - are also the basis of depressive personality. Disturbances in mood can have effects on a person's emotional state and social life that resemble a personality disorder. And people are more easily demoralized and recover more slowly from any stress or misfortune if they are pessimistic and self-critical by nature - or emotionally unstable, impulsive, and hypersensitive to loss.
Looking for causes
Like major depression, dysthymia has roots in genetic susceptibility, neurochemical imbalances, childhood and adult stress and trauma, and social circumstances, especially isolation and the unavailability of help. Depression that begins as a mood fluctuation may deepen and persist when equilibrium cannot be restored because of poor internal regulation or external stress.
Dysthymia runs in families and probably has a hereditary component. The rate of depression in the families of people with dysthymia is as high as 50% for the early-onset form of the disorder. There are few twin or adoption studies, so it's uncertain how much of this family connection is genetic. Nearly half of people with dysthymia have a symptom that also occurs in major depression, shortened REM latency - that is, they start rapid eye movement (vivid dreaming) sleep unusually early in the night.
The stress that provokes dysthymia, at least the early-onset form, is usually chronic rather than acute. Studies show that it usually has a gradual onset and does not follow distinct upsetting events. In old age, dysthymia is more likely to be the result of physical disability, medical illness, cognitive decline, or bereavement. In some older men, low testosterone may also be a factor. Physical brain trauma - concussions and the like - can also have surprising long-term effects on mood that often take the form of dysthymia.
At least three-quarters of patients with dysthymia also have a chronic physical illness or another psychiatric disorder such as one of the anxiety disorders, drug addiction, or alcoholism. In these cases, it is difficult to distinguish the original cause, especially when there is a vicious cycle in which, say, depression exacerbates alcoholism or heart disease exacerbates depression.
The same vicious cycle exists in many other situations. For a person who is vulnerable to depression, every problem seems more difficult to solve and every misfortune causes more suffering. Depressed people give discouraging interpretations to every event in their lives, and these interpretations make them still more depressed. Depression often alienates others, and the resulting isolation and low social support make the symptoms worse. The experience of chronic depression may sensitize the brain to stress, heightening its vulnerability to further depression.
Treatment
Most people with dysthymia are undertreated. They usually see only their family doctors, who often fail to diagnose the problem. They may only complain about physical symptoms, or fail to complain at all because the disorder has become so much a part of them that they believe that is simply how life is. In older people, dysthymia may be disguised as dementia, apathy, or irritability.
A physician might ask an open question like, "How are things at home?" - follow with, "Have you been feeling down, depressed, or sad?" - then go on to ask whether the symptoms have affected a patient's home life, work, or personal relations. There are also several brief screening questionnaires, including the Hamilton Rating Scale for Depression and the Patient Health Questionnaire. If the answers suggest dysthymia, a standard clinical interview can be used to confirm the diagnosis.
Like major depression, dysthymia is treated with psychotherapy and medications - usually the same medications and the same kinds of psychotherapy. The most common drug treatments are selective serotonin reuptake inhibitors like fluoxetine (Prozac) and sertraline (Zoloft), or one of the dual action antidepressants such as venlafaxine (Effexor). Some patients may do better with a tricyclic antidepressant like imipramine (Tofranil).
Supportive therapy provides advice, reassurance, sympathy, and education about the disorder. Cognitive therapy identifies and corrects thought patterns that promote self-defeating attitudes. Behavioral treatment improves social skills and teaches ways to manage stress and unlearn learned helplessness. Psychodynamic therapy helps patients resolve emotional conflicts, especially those derived from childhood experience. Interpersonal therapy helps patients cope with personal disputes, loss and separation, and transitions between social roles.
