context: Cyclothymia -- or cyclothymic disorder -- is a relatively mild mood disorder. In cyclothymic disorder, moods swing between short periods of mild depression and hypomania, an elevated mood. The low and high mood swings never reach the severity or duration of major depressive or full mania episodes. People with cyclothymic disorder have milder symptoms than occur in full-blown bipolar disorder. From 0.4% to 1% of the U. S. population has cyclothymia. Equal numbers of men and women are affected. Symptoms usually begin in adolescence or young adulthood. The onset of cyclothymia is frequently hard to identify. In cyclothymia, moods fluctuate from mild depression to hypomania and back again. In most people, the pattern is irregular and unpredictable. Hypomania or depression can last for days or weeks. In between up and down moods, a person might have normal moods for more than a month -- or may cycle continuously from hypomanic to depressed, with no normal period in between. Compared with more serious mood disorders, the mood symptoms of cyclothymia are mild. Depressive symptoms in cyclothymic disorder never reach the criteria for major depression. Elevated mood never reaches the definition for mania. Cyclothymia can straddle the line between mental illness and normal variations in mood and personality. Some people with mild symptoms are highly successful in life, driven by their hypomania to express individual talents. On the other hand, chronic depression and irritability can ruin marriages and professional relationships. Many experts say cyclothymic disorder is a very mild form of bipolar disorder. No one is sure what causes cyclothymia or bipolar disorder. Genetics play a role in the development of both these disorders. People with cyclothymia are more likely to have relatives with bipolar disorder and vice versa. Cyclothymia frequently goes undiagnosed and untreated. Most people's symptoms are mild enough that they do not seek mental health treatment. In fact, some people resist the idea of treatment, which reduces their "up" episodes as well as "down." The depressive symptoms of cyclothymic disorder are typically more frequent, unpleasant, and disabling than the hypomanic symptoms. Feelings of depression or instability are usually what cause people with cyclothymia to seek help. No medicines are specifically approved for the treatment of cyclothymia, although mood stabilizers such as lithium or lamotrigine are sometimes recommended as a possible strategy to reduce mood fluctuations. Antidepressants such Prozac, Paxil, or Zoloft are generally not recommended unless someone develops a full major depression, which, by definition, does not occur in cyclothymic disorder. There is also a small risk that antidepressants could trigger or worsen mania symptoms in a subgroup of vulnerable people. Antidepressants alone also are not known to improve fluctuations in mood, which are hallmark characteristics of cyclothymic disorder. Technically speaking, when elevated or depressed moods become severe, a person no longer has cyclothymia, but rather has bipolar disorder. This progression to more severe symptoms can happen, and this is when many people first receive treatment. Cyclothymia may wreak havoc on the personal lives of people with the disorder. Unstable moods frequently disrupt personal and work relationships. People may have difficulty developing stable work or personal relationships, instead moving through short-lived romances or erratic job performance. Impulsive behavior can be self-destructive and lead to legal problems. People with cyclothymic disorder are also more likely to abuse drugs and alcohol. Up to 50% of people with cyclothymia may also have a problem with substance abuse. Over time, people with cyclothymia are at increased risk of developing full-blown bipolar disorder. Limited data suggests they are at higher risk of suicide. Some clinicians think that mood stabilizers may help to reduce this risk, although more research is needed to determine whether they may be effective.