I feel compelled [see? already a kodakADD moment...] to respond, having just responded to both the OCD and TS/tics threads, although about PANDAS/GABHS. I've been through BP and schizo boards, too, tracking down ever more input on whatever this is I apparently have. Actually, the "official" [clinical] Dx I have is [Adult] AD[H]D [inattentive] Dx with possible BP [iI], although the latter has been mostly "ruled out" through therapy/experience, despite this kind of behavior and these blasted waxing'n'waning tics, which might indicate TS and OCD if heritable, otherwise probably something like PANDAS, or hunoz, borderline, split, or multiple personality disorder or something. Phhht!
I am really not making light of this but just telling you what's going on in my case and saying that, yes, there can be more than one thing going on. In my case, there appears to be, anyway, eg PANDAS (which is close symptomatically to OCD/TS) and ADD (which is close to BP, which is near if not in personality disorder-land, which is near the -lepsies [epi-, narco-, etc.])
As I noted in one reply, the Dx for me is significant because one disorder implies heredity and another doesn't. But one could have both! ie I might have PANDAS and ADD or/and TS/OCD! Eek!
But there are some objective things that help to differentiate these problems. For example, best as I can tell, PANDAS results in some kind of basal ganglionic pathology (engendering rheumatic fever in a more severe form), which affects one's psyche in various neuron[t]ic ways, eg/esp. tics ephemerally, OCD more monotonously, etc. Now, this area is very close to if not the or in the dopamine "power station" in your mental 'internet', so to speak, and glitches in its "[re-]uptake" through associated neuro-transmission faciloities can cause all kinds of problems, ranging from glitches, to static and distortion, all the way to service disruptions, brownouts and ultimately blackouts. And in ADD there seems to be something wrong in the area of filtering realtime inputs, focusing on a manageable subset, staying on track and recording and playing back programs. And these involve such etiologic, diagnostic, therapeutic, and prognostic complexities, ambiguities, and uncertainties, and they are so hard to verify, that it is all pretty much overwhelming, even to the pdocs.
But what seems to be most perplexing and dissatisfying to people is that there don't seem to be many 'smoking guns'', like MRI, Xray, or DNA signatures for sure, although there are some MRI's of ADD and EEGs of epilepsy and some others that seem to be definitive if not precise with respect to diagnosis and therapy. And, in the year 2004, with all its supercalifragilistic biocybertechnology, it seems like there should be more certainty and efficacy in sorting this all out and being able to fix it for everybody who has 'it', right?
Like you, I can appreciate this academically, but way much less as a patient/victim or, worse, a parent of one [or more!] And so I empathize with you and wish you the best!