It seems to me that schizophrenia (and especially MDD) are imperfect, albeit useful, categories that umbrella together multiple independent etiologies.
If so, the question becomes 'why not both neurodevelopmental and neuro degenerative?'. From what I can tell, there are a subset of people given a schizophrenia diagnosis who follow the predictable neuro developmental course you describe. The map in this case matches the territory very well.
Others' prognosis are more variable (but still meet criteria for schizophrenia). Like you mention, maybe immune or neuro degenerative processes are at play.
I really don't know what to make of the studies you go through because of concern of this problem. It's promising to find any correlations!
I think that’s definitely possible, and have heard Robin Murray say that schizophrenia will one day be like heart failure, with multiple disease pathways.
However, I haven’t seen convincing evidence that the disorder can be subtyped in practice. When looking at inflammatory markers, for example, they seem to be generally a little raised across the population with schizophrenia rather than raised in a subgroup and normal in others.
Likewise in this Jonas study - I don’t get the sense they found a subgroup who had early cognitive deficits and a subgroup with cognitive decline but rather these were found across the entire schizophrenia/psychosis group. Maybe they didn’t look for cognitive trajectories in this way though!
It seems to me that schizophrenia (and especially MDD) are imperfect, albeit useful, categories that umbrella together multiple independent etiologies.
If so, the question becomes 'why not both neurodevelopmental and neuro degenerative?'. From what I can tell, there are a subset of people given a schizophrenia diagnosis who follow the predictable neuro developmental course you describe. The map in this case matches the territory very well.
Others' prognosis are more variable (but still meet criteria for schizophrenia). Like you mention, maybe immune or neuro degenerative processes are at play.
I really don't know what to make of the studies you go through because of concern of this problem. It's promising to find any correlations!
I think that’s definitely possible, and have heard Robin Murray say that schizophrenia will one day be like heart failure, with multiple disease pathways.
However, I haven’t seen convincing evidence that the disorder can be subtyped in practice. When looking at inflammatory markers, for example, they seem to be generally a little raised across the population with schizophrenia rather than raised in a subgroup and normal in others.
Likewise in this Jonas study - I don’t get the sense they found a subgroup who had early cognitive deficits and a subgroup with cognitive decline but rather these were found across the entire schizophrenia/psychosis group. Maybe they didn’t look for cognitive trajectories in this way though!