In the Questions and Answers section of BipolarConnect on HealthCentral, Angst asked a very good question:
There are tons of articles and books and information available for bipolar disorder. Bipolar I and II are mentioned abundantly, yet cyclothymic disorder usually only gets a few sentences, a paragraph. It is very distressing and demeaning for someone with this disorder as it feels like it is just brushed off and unimportant.
Angst is right: Cyclothymia, or cyclothymic disorder, is often overlooked and, by those who have heard of it, very frequently misunderstood.
Let's get this straight right at the beginning: Cyclothymia is not "mild bipolar disorder." Yes, it is less severe than bipolar I or bipolar II disorder, but there is nothing "mild" about it.
Hypomania in bipolar 2 disorder and cyclothymia are the same. That means people with cyclothymic disorder may spend recklessly, indulge in all the potentially damaging behaviors of hypersexuality, be unable to focus on a single subject for very long, have racing thoughts, behave inappropriately, be unusually irritable or aggressive, and have many other symptoms that go into the makeup of hypomania.
The difference between cyclothymia and bipolar II is in the severity of depression symptoms. The DSM-V diagnostic criteria for cyclothymic disorder are as follows (emphasis mine):
"For at least 2 years, the presence of numerous periods with hypomanic symptoms ... and numerous periods with depressive symptoms that do not meet criteria for a Major Depressive Episode."
So what's the difference between cyclothymic depression and a major depressive episode? Less than you might think: it is that a person with cyclothymia does not have thoughts of suicide and is never completely incapacitated by depression. Thus depression can still be quite severe in cyclothymia.
Just as in bipolar disorders, both hypomanic and depressive symptoms of cyclothymia must "cause clinically significant distress or impairment in social, occupational, or other important areas of functioning." That's a serious condition.
Given this, I'll go out on a limb here and say it's possible that cyclothymia may often be misdiagnosed as bipolar II disorder. Also, in some references cyclothymic disorder is called "bipolar III disorder." Maybe people with cyclothymia would get more respect if they called it bipolar III instead?
Angst, you're not alone. Thanks for bringing up this important topic.