Recognizing the different types and intensities of mood episodes, the DSM-5 (the Diagnostic and Statistical Manual of Mental Disorders, the book that describes mental health diagnoses) has divided the diagnosis of bipolar disorder into seven basic categories. Each one is defined by a particular pattern of severity and length of manic, hypomanic or depressive symptoms that occur.
"Bipolar I Disorder" is used with patients who demonstrate full-strength manic and depressive episodes.
"Bipolar II Disorder" is used with patients who demonstrate full-strength depression, but only hypomanic episodes rather than full-strength manias.
"Cyclothymic Disorder" is used to describe patients who demonstrate repeated mood swings which are never quite severe enough to qualify as major depressive or manic episodes.
"Substance/Medication-Induced Bipolar and Related Disorder" is used when the symptoms happen during or soon after taking a substance or stopping use of a substance that is capable of producing the bipolar symptoms. You can read more about this in our section on Mental Health Conditions Similar but Distinct from Bipolar Disorder.
"Bipolar and Related Disorder Due to Another Medical Condition" is used when symptoms are produced by a medical condition (not another mental health condition).
"Other Specified Bipolar and Related Disorder" applies when symptoms cause significant distress or impairment, but do not meet the full criteria for any of the other disorders in this category. This is used when the clinician specifies the reasons that criteria are not meet (for example, not quite enough days or symptoms displayed to trigger the full diagnosis).
"Unspecified Bipolar and Related Disorder" is used to describe situations where the clinician chooses not to specify the reason that the criteria for one of the other types are met or when there is not enough information available to make a more specific diagnosis.
We'll have more to say about DSM bipolar diagnoses in the chapter on diagnosis.
Length of and Changing Mood Swings
Besides the energy or intensity, the other important factor relating to bipolar mood swings has to do with how long each episode lasts, and how rapidly they change (sometimes called "periodicity"). Most of the time bipolar mood swings happen slowly over periods of weeks and months. Usually, less than four complete mood cycles occur within a given year, and each mood episode might last up to two months.
There is generally a period of relatively normal mood that occurs between mood episode extremes. However, some individuals with bipolar disorder do not experience this. Instead, they experience this period as a point in time when their mood symptoms are milder than normal (rather than being completely gone). For example, a person who is clearly between episodes might still feel low on some days or slightly manic on others.
Though less common than the longer cycling forms of bipolar disorder, a rapid-cycling type of bipolar disorder is also recognized. This specifier is used when manic, hypomanic or major depressive episodes have happened at least four times during the previous 12 months. Rapid cycling bipolar conditions are thought to occur in 20% or less of all bipolar patients.
Rapid cycling in any form of bipolar disorder tends to be associated with a poorer long-term outcomes. Those with rapid cycling bipolar disorder often have more difficulty holding their lives together than those who have bipolar disorder with longer cycles between mood episodes