There are some sites that summarize and explain this stuff better than I can right now that you might find helpful/ interesting:
http://www.psycheducation.org/depression/02_diagnosis.html#soft
This even has its own graph showing the spectrum and explaining the concept.
This comes from the home site, http://www.psycheducation.org/ , which has many interesting information about bipolarity, specifically BPII. It's a decent read and it puts things in an interesting perspective. I would also recommend reading the page on mixed states and viewing them as "waves" :
http://www.psycheducation.org/depression/Waves.htm
Excellent example :)
I love numbers... makes perfect sense that way!
Maybe think of it like diabetes. Diabetes checks your hemoglobin A1c which tests for average levels of glucose in your blood every 3 months.
Hypoglycemic 4.7% and down
Normal is 4.8%-5.6%
Pre-Diabetes is 5.7%-6.5%
Diabetes is 6.6% and up.
I've seen people with A1c results at high as 17%, which is pretty dangerous.
Now, people with bipolar don't have a test like an A1c, but I would say that if A1c glucose levels = bipolar mood levels (with smaller numbers equalling depression and higher numbers mania) it would look like this:
Depression 4.7% and down
Normal 5.0%-5.6%
Cyclothymic 5.7%-6.0%
Bipolar II 6.1%-7.0%
Bipolar I 7.1% and up
I think just like people with diabetes who take too much insulin can have sever hypoglycemic episodes, it is the same with people and bipolar taking an AD, except instead of hypoglycemia we get mania. When people with just depression take an AD it bumps them up into that normal range.
Anyway, I just thought maybe thinking of it at a different angle would help.
From what my last psychiatrist said... the spectrum was like this:
unipolar depression
to
high mania and severe depression.
So BP2 would fall somewhere in the middle, if that makes sense.
So the spectrum is more of a 'doesn't fluctuate moods' to 'mood fluctuates wildly', not a depressed to manic spectrum.
There are a bunch of diagnoses on that scale, and each one has different diagnostic criteria.
I was diagnosed as Bipolar II, which could be seen as just another point on that scale. I was on an anti-depressant and a mood stabalizer and it was horrible.
The scale you're talking about would really depend on the exact symptoms. My symptoms, even when they went back to being untreated, wouldn't be the same as someone with major depressive disorder or someone who was just straight Bipolar I.
So really I'm not sure about this theory, I suppose. But that's just my two cents.
I can only speak for myself on this. Where was I before being diagnosed? Exactly where I am right now except without lithium. Up until last year I was still a rapid cycler, although not cycling as fast as I am since last May, which is when things got bad. I had possible psychotic episodes multiple times in my life starting in childhood. I was never treated or medicated except for 2-3 months of therapy in 1991, a little grief counseling after my mom died in 1992, and 2 weeks on Abilify in 2006 which caused me to have a bad reaction to it. I never took an AD.
I think what I was trying to say about this is that the spectrum spans between one mood disorder (unipolar depression) to another (bipolar I), not just from the state of depression to the state of mania. In fact, this view of placing depression and mania at two ends of a spectrum does not support the concept of mixed mood states, wherein both mania and depression are present at the same time (as is seen in dysphoric mania/ agitated depression). They are not entirely two discrete states, because they can mix together in countless way.
Again, this is only what I've been reading in recent publications, and so this spectrum view of bipolar disorder should still be viewed as a theoretical approach that is guiding a lot of current research.
Another way to visualize it simply, like what ecritmaman had said:
UP----BPII---------BPI
Person A: UP----BPII-x------BPI
(This person would be classified as BP II, because they are over the arbitrary spectrum threshold for BPII; however, they do not experience full blown manic episodes, so their place on the spectrum is placed between BP II and BPI depending on the specific course and symptoms of their personal illness. When given an AD, it could be very likely that the medication will cause hypomania, and that the person may go on to experience spontaneous hypomanias; their moods are destined to fluctuate more so than a unipolar depressed person, or even a person with cyclothymia)
Person B: UP--x-BPII----BPI
(This person would be classified as depressed, they have some "soft signs" of bipolarity, and they are getting close to the point where their moods are going to experience fluctations. It could be possible that an AD would bump them up over the threshold for BP II.)
The places on the poles indicate the particular case of a mood disorder the individual has. This place on the spectrum can change when factors are added in, such as an AD that bumps a UP patient who is bordering on BP; this could also happen when a person with BPII, AD induced or not, continues to worsen and begins to experience worsened manic episodes. Their place on the spectrum would be shifted closer to the BPI point at the far end. A person diagnosed as BPI from the very beginning, who has a "classic" form of the illness would have their plot on the spectrum at the very end. There are so many possible variations and manifestations of the disorder, because each person is going to experience different symptoms. In order to provide efficient treatment, we need to have these discrete points, but we also need to recognize that most people are falling all along this spectrum line due to the vast variations that manifest.