>>21000983Dorsolateral frontal lobe syndrome goes by many names. Some of which include "convexity syndrome," "apathetic syndrome," "abulia," or "frontal lobe avolitional syndrome." I like convexity syndrome so let's use that for the time being.
Some coarse brain disease which might cause convexity syndrome includes brain damage from head trauma/stroke, hallucinogen use, and pick's disease (frontotemporal dementia), to name a few.
Idiopathic convexity syndrome is synonymous with schizophrenia spectrum disorders.
By itself, it might be called "schizoid disorder."
In the presence of subcortical aphasia and positive psychotic symptoms, depending upon the severity of the latter it may be called either "schizotypal disorder" or "schizophrenia."
In all three the presence of convexity syndrome is required to make the diagnosis.
Convexity syndrome is not the only cause of negative symptoms. On the psychiatric side, melancholic depression causes negative symptoms. On the neurologic side, parkinson's disease is a well known cause of negative symptoms. There are other causes but those are the big two.
Now that's taking a whole bunch of different phenomena together and labelling it "negative symptoms." In the case it's not all due to one cause, it could look like, for an extreme example,
>flat affect and social withdrawal due to autism>avolition and anhedonia due to carbon monoxide poisoning (fahr's syndrome)>alogia due to previous strokeAnd so on. You get the picture? Not all of those things can be bundled together into "negative symptoms" because that itself is a syndrome, and syndromes cannot be diagnosed if their constituent parts are all due to separate causes. It can look like all the boxes are checked off but actually looking at it further it's easy to see it's not the same thing at all.
This is a really longwinded way of saying good news! If you don't have convexity syndrome then all schizophrenia spectrum disorders are ruled out!!
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