Bipolar disorder is divided into two subtypes: I and II. People with bipolar I disorder can experience both manic and hypomanic episodes over the course of their lives, whereas only hypomania occurs in bipolar II. Other important differences include people's responses to medications, particularly antidepressants, and the functional impact of each illness.
Bipolar Disorder Is a Mood Disorder
Mood swings are the defining characteristic of both bipolar I and II. From this perspective, there is little that differentiates the two; a person with either condition can experience periods of euphoria alternating with equally long periods of depression or, if not, euthymia (mood that is neither euphoric nor depressed). While physiologic triggers such as disruptions in the sleep-wake cycle or the abuse of certain drugs can precipitate these fluctuations, they can just as easily occur without any apparent trigger at all. And though the occurrence of just one such episode is enough to make the diagnosis in either case, recurrence is the rule: A person with bipolar disorder can expect to have many manic or hypomanic episodes over the course of his lifetime, especially if he chooses to forgo treatment.
Definition of Mania
According to the diagnostic manual of the American Psychiatric Association, the DSM-IV-TR, mania is defined as "a distinct period during which there is an abnormally and persistently elevated, expansive or irritable mood" plus at least three of the following symptoms if the mood is elevated or expansive; four are required if the mood is merely irritable:
- grandiosity (i.e., exaggerated notions of self-esteem)
- decreased need for sleep
- more talkative than usual or more difficult to interrupt when talking
- an outwardly expressed "flight of ideas" or a subjective experience of racing thoughts
- increased distractibility
- increased goal-directed activity (e.g., in work, school or social life) or increased psychomotor activity (i.e., appearing "hype" or "bouncing off the walls")
- excessive involvement in high-risk, pleasurable activities (e.g., reckless gambling or spending, or sexual promiscuity)
Important Features of Mania
A manic episode will invariably disrupt a person's life to the point of "marked impairment" in occupational or social functioning, frequently necessitating hospitalization. Psychotic symptoms, such as auditory hallucinations or delusional beliefs, are also frequently part of the clinical picture. Furthermore, these symptoms must persist for at least seven days to be considered true mania, unless they are so severe that hospitalization becomes necessary, in which case the duration requirement is waived.
How Is Hypomania Different?
Where the DSM-IV-TR is concerned, two things distinguish mania from hypomania: duration and severity. First, hypomania will never result in hospitalization, and functioning is impaired mildly, if at all. In fact, a state of hypomania frequently results in increased productivity and functional enhancement, a product of high levels of energy and enthusiasm coupled with unusually quick and creative thinking. Psychosis, if present, denotes mania and never hypomania. Finally, the minimum duration of symptoms for hypomania is reduced from seven days to four.
Practically speaking, the difference in duration between the two is more pronounced: Whereas an untreated manic episode can persist for months, hypomania typically runs its course in a matter of days to weeks.
Other Differences and Similarities
According to research cited in Dr. Franco Benazzi's paper in the March 17, 2007, edition of the "Lancet," several other clinical features distinguish bipolar II from bipolar I. These include the fact that depression is more common in bipolar II, and bipolar II is less likely to require mood stabilizing medication. Furthermore, the use of antidepressants in bipolar II is less likely to "switch" a person from a depressed episode into mania or hypomania, as compared with bipolar I.
Beyond sharing the same core diagnostic features, there are other similarities, such as average age of onset (15 to 30 years) and the character of the depressive component of each illness: When depression occurs in either disorder, it is more likely to include atypical features, such as oversleeping and overeating versus non-bipolar (unipolar) depression.
References
- "The MGH Guide to Psychiatry in Primary Care"; Approach to the Patient With Elevated, Expansive or Irritable Mood; G. Sachs; 1998
- "Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition"; American Psychiatric Association; 2000
- "Lancet "; Focus on Bipolar II Disorder and Mixed Depression; 2007
