The thing is that with every psychiatric condition, there are different groups of people who have that condition. Each group has characteristic clinical features and underyling pathology. One person may have a problem with dopamine, while another has a problem with GABA, and so on...

That's why it's so difficult to treat. Because my 'bipolar' may have a completely different biological basis than your 'bipolar'.

They have some hard data on this with OCD and trichotilloamania. That's why some people with OCD respond well to SSRIs, and others (like me) don't. Because only some people with OCD have a serotonin issue. The rest have issues with other neurotransmitters.

I think a more useful thing than a linear spectrum is organizing it by comorbidities. A venn diagram would be more useful.

what I think are different categories of bipolar:
- people who are predominantly depressed/have 'BP II'
- comorbid bipolar/ADHD (+/-OCD)
- bipolar with psychotic features
- bipolar that is predominantly manic or hypomanic, with little depression
- true 'cyclic' bipolar with regular, distinct cycles of severe mania-severe depression ('classic' bipolar)
- people who predominantly have mixed states/agitated depression

I think I'm in the category of comorbid bipolar/ADHD+OCD. As in, I have an issue with impulse control and compulsion control.