If you were to ask Emil Kraepelin, a German psychiatrist, in the late 1800s/early 1900s about his observations of mixed episodes, he would describe possible mood combinations of anxious mania, mania with poverty of thought, inhibited mania, manic stupor, excited depression, and depression with flight of ideas (1). If you looked in the current Diagnostic and Statistical Manual of Mental Disorders - Fifth Edition (DSM-5) used in the US today, you would rather see a primary bipolar episode being experienced (depression, hypomania, or mania) with the specifier "with mixed features" added if it was what was more commonly called a "mixed episode" in earlier DSM editions. The primary episode is the mood state where most symptoms are represented, but some symptoms of another mood state also exist.

According to the DSM-5, one cannot have a mixed state of hypomania with also full manic features. If any full manic features appear in a given episode, I believe it is automatically a manic episode. However, one can certainly have more manic symptoms than depressed symptoms, and vice versa. I believe (but am not 100% sure) that if one mood state (i.e. depression or mania) has especially severe symptoms, that mood state may be considered the primary mood state, even if there are more symptoms of the other mood state, but they are are milder than the worst symptom of the other state.

When I have experienced mixed states (mixed features) in the past, mine were generally the classic type where I did have some depressive symptoms simultaneously as manic symptoms. Consider the labels Emil Kraepelin described, such as excited depression. Excitement or high energy levels are usually associated with mania, but one can be severely depressed with high energy levels. I have always considered mixed states to be particularly dangerous for me, considering the "mix" of depressive and manic symptoms I often had.

General "rapid cycling" is defined as having 4 or more bipolar episodes per year. This can mean that you could potentially be purely depressed for one whole month (meeting depression criteria), stable 2 weeks, hypomanic with mixed features for 6 weeks (meeting criteria), stable for 2 months, developing a full blown mania for 5 weeks (meeting criteria), and depressed for 3 months, then stable for the rest of the months. That equals 4 episodes.

"With rapid cycling" in the DSM-5 is a specifier, like "with mixed features". In the DSM-5, the terms "ultra rapid cycling" (several pure episodes within week/month) and "ultra ultra rapid cycling" (several pure episodes within 24 hours) are not used. That obviously doesn't mean that these types of mood events don't happen. It's my assumption (I'm not sure) that such episodes are simply given the "with rapid cycling" specifier.

I have definitely heard of people call rapid-type cycling "mixed episodes". I believe many psychiatrists have/will call such events mixed episodes at times, too, but they are different than the mixed features I described where episodes of depression and hypomania/mania are experienced simultaneously. But simultaneous in my book is not 4 hours of pure depression and then 6 hours of pure hypomania.

I definitely know that my episodes have often started "pure" and then turned "mixed" or totally switched on a dime to the opposite mood "pole". I definitely see that as rapid cycling. The only thing that is unclear to me is what one calls a three-day period where you are purely depressed one day, wake up hypomanic the next day, become depressed the third day, and then become stable. Is that rapid cycling? I'd have to ask my psychiatrist. I don't know. I do know that one psychologist I spoke with told me that she calls such situations "mood lability", where minimum episode length is not met.

The minimum length requirement for hypomania is 4 consecutive days, according to the DSM-5. The minimum length of a manic episode is 1 week, or if it's so severe that it results in hospitalization. The minimum length of a depressive episode is a 2 week period, according to the DSM-5. So again, how would a doctor label a three-day wild mood bonanza? Well, I guess if it resulted in hospitalization from full blown manic symptoms, it would be a manic episode. But what if it was only three days and there were pure depressive hours and pure hypomanic hours without hospitalization? Is that just mood lability? And what about only three days where there were simultaneous depressive and hypomanic or manic symptoms? Is that considered an episode? Or again, just mood lability, unless you are hospitalized for the manic symptoms?

This is very confusing! I think a lot of psychiatrists are not thrilled with the DSM-5 completely. I think some psychiatrists are not so picky about minimum episode lengths. That's just my guess.

Resources (sorry not in APA format):

Surviving Manic Depression - A Manual On Bipolar Disorder For Patients, Families, and Providers by E. Fuller Torrey, M.D. and Michael B. Knable, D.O., Copyright year 2002 (pp. 38-40)

Diagnostic And Statistical Manual of Mental Disorders - Fifth Edition by American Psychiatric Association, Copyright year 2013 (pp. 123-127, 149-151)

Anything in RED font represents my own questions or uncertainties.