Hi, may I ask, do you know of any resources with detailed info/explanations of the different kinds of "odd speech" (vague, circumstantial, metaphorical, over-elaborate, stereotyped, stilted, etc etc., preferably with examples) and, maybe also how they might present differently in various disorders (especially personality disorders)? They always seem to be lumped together as something like "odd/peculiar speech" in symptom lists, but surely some types should be more common in particular disorders??
"odd speech" usually refers to "formal thought disorder" (FTD), or disorganised speech. it's present in a lot of disorders, including psychotic disorders, neurodevelopmental disorders (e.g. echolalia, repeating words, common in autistic people), bipolar & mood disorders, neurocognitive disorders (like dementia), anxiety disorders...
in personality disorders, i assume it'd be limited to cluster A PDs, since they're on the schizophrenic spectrum. on the other hand, FTD is also present in depression which is very often comorbid with PDs, and it also happens in 6% of the non-disordered population, so cluster b & c PDs could very well experience FTD as well!
basically, pretty much everyone can experience FTD, but it's most common in "severe" disorders like psychotic & neurodevelopmental disorders. the only PD that has FTD as a symptom listed in the criteria is STPD.