Cyclothymic Disorder

Cyclothymic Disorder is a pattern of mood swings that vary from mild elation to mild Depression.  Cyclothymic Disorder is similar to Bipolar Disorder, in that the person will experience shifts between 'highs' and 'lows', however these elated and sad moods never reach full Depression or Mania.  The elated moods are termed hypomania as they consist of a lesser degree of manic symptoms such as:

• Becoming more sociable
• Feeling the need to talk more 
• Being overfriendly 
• A decrease in the amount of sleep

Cyclothymic disorder usually develops early in adult life leading to a chronic course of mood swings.  These mood swings can last several months, becoming stable only to change again.  Due to the mildness of the mood changes, the person suffering from Cyclothymia will rarely bring it to medical attention. 

Cyclothymic Disorder is most common in relatives of people who suffer from Bipolar Disorder.  Cyclothymic Disorder may persist throughout adult life, or it may temporarily or permanently cease.  However it is often a precursor to developing Bipolar II Disorder.

References:

The Merck Manuals: Online Medical Library;

The Cyclothymia Workbook: Learn How To Manage Your Mood Swings & Lead A Balanced Life
Prentiss Price, Ph.D
2005

Dysthymia and Cyclothymia in psychiatric practice a century after Kraepelin
Journal of Affective Disorders, 62, 17-31
Hagop Souren Akiskal
2001