Dictionary definitions of episode abound, but the nearest lay definition that fits a bipolar disorder episode is "an incident or event that is part of a larger sequence." The larger sequence, of course, is the ongoing flow between the highs and lows of manic depression.
The Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition (DSM-IV) has strict durations for each type of episode that may occur in bipolar disorder:
- A manic episode must last at least one week unless hospitalization is necessary - then the episode may be shorter and still be classed as manic.
- A hypomanic episode must last at least four days.
- A major depressive episode must last at least two weeks.
- A mixed episode must last at least one week with symptoms present "nearly every day."
- In a manic episode, there must be a sustained and abnormally elevated, expansive or irritable mood throughout the period.
- In a hypomanic episode, there must be a sustained and elevated, expansive or irritable mood throughout the period - but the word "abnormally" is omitted from the description.
- In a major depressive episode, at least one of the symptoms must be depressed mood or loss of pleasure or interest.
- In a mixed episode, the criteria for both a major depressive episode and a manic episode must be met.
- Online Psychological Services (2003). Diagnostic and Statistical Manual of Mental Disorders. "Bipolar I Disorder." Retrieved September 29, 2006 from http://www.psychologynet.org/bipolar1.html#major.
- episode. (n.d.). The American Heritage® Dictionary of the English Language, Fourth Edition. Retrieved September 29, 2006, from Dictionary.com website: http://dictionary.reference.com/browse/episode.