“If the human brain (mind) was simple enough for us to understand it, we would be too dumb to understand it”. I don’t know who said it but my point is that I cannot imagine any health care pathology to be so simply one dimensional that it’ll fit on a continuum.

Perhaps it helps to understand that a spectrum can be comprised of a cluster of continua: a possibility space of which any subset can be observed. Like each colour in the light spectrum. The continuum notion in that case can refer to its brightness. Same in the case of emotions. We don’t just experience one emotion at any given time although there’s a prominent one and others might be subdued. How we cluster certain aspects, such as traits in mental health as well as the threshold to diagnose anyone is of course arbitrary. Severities in presentations are perhaps seen as a continuum, but the underlying structure that aids in defining it, is a spectrum.

I feel like people confuse the term spectrum with the term continuum. Fading from black to white through gray is a continuum. Rainbow colours are a spectrum. In mental health, most conditions have no aetiology - or it is not considered, and the condition is described or defined by signs and symptoms, and not something like a bloodtest. The weight of each of these signs and symptoms is what makes up the spectrum. When someone is on the spectrum of whatever condition, it means the sum of those weights exceed a value that causes some detriment to the individuals quality of life. Maybe I’m spliting hairs but I thought to share my understanding.